HOME LONGEVITY LIBRARY CATALOG INDEX TO THE McCARRISON PAPERS
'Malnutrition is responsible for widespread impairment of human efficiency and for an enormous amount of ill health and disease, reduces the resistance of the body to tuberculosis, and enhances the general incidence and severity of familiar diseases; mortality rates in infants, children and mothers are higher in ill-fed than in well-fed populations; food consumption at a level merely sufficient to prevent malnutrition is not enough to promote health and well-being.'
'A sound food and nutrition policy must be adopted by each Government if national diets are to be progressively improved, specific deficiency diseases eliminated, and good health achieved.'
'Given the will, we have the power to build in every nation a people more fit, more vigorous, more competent; a people with longer, more productive lives, and with more physical and mental stamina than the world has ever known. Such prospects, remote though they may be, should serve as a stimulus in undertaking immediate tasks and overcoming immediate obstacles.'
Report of the United Nations Conference on Food and Agriculture, Hot Springs, Virginia, United States of America, 18th May-3rd June 1943.
PUBLISHERS' FOREWORD
The three lectures which form the subject matter
of this book were the Cantor Lectures of 1936 delivered before
the Royal Society of Arts by Sir Robert McCarrison, formerly Director
of Research on Nutrition in India. The publication of the lectures
in 1936, considered in retrospect, was an event of outstanding
importance, as witnessed by the constant reference to them by
subsequent writers upon Nutrition and kindred subjects.
It came to the notice of the present publishers
that the pamphlet in which the lectures were first published had
been out of print for some years. It seemed regrettable that it
should no longer be available, in view of the light which the
lectures threw on the relation of food and nutrition to public
health and of the preoccupation of government and people with
this subject at the present time. With this in mind the publishers
sought the consent of the Council of the Royal Society of Arts
and of the author to reprint the lectures; this was willingly
given.
The thesis, sustained in these lectures, that
'the greatest single factor in the acquisition and maintenance
of good health is perfectly constituted food', is now an established
truth. Various publications of the League of Nations have borne
witness to it; and the United Nations Conference on Food and Agriculture,
held at Hot Springs, Virginia, in 1943, has set its seal upon
it. This Conference declared 'that the first essential of a decent
standard of living is the provision to all men of those primary
necessities which are required to promote freedom from disease,
and for the attainment of good health'; and, 'that the most fundamental
of these necessities is adequate food. . . . ' These
lectures provide experimental proof of 'the fundamental importance
of food in relation to health'. It is hoped that their re-publication
will help to extend the knowledge of this vitally important fact
among a wider public, to promote the progressive improvement of
national diets and, consequently, of national health.
CONTENTS
I. FOOD, NUTRITION, AND HEALTH
The cell. Food. Nutrition. Health. The experimental method in research on nutrition. Food and physical efficiency. Freedom of well-fed animals from disease. A good diet and a bad one. Food and peptic ulcer. Experimental beri-beri and 'stone'. Variety of disease in improperly fed animals.
II. RELATION OF CERTAIN FOOD ESSENTIALS TO STRUCTURE AND FUNCTIONS
OF THE BODY
Oxygen and water. Proteins. Mineral salts: Calcium, Phosphorus, Iron, Iodine. The Vitamins: A, B, B2, C, D. Vitamins in general.
III. NATIONAL HEALTH AND NUTRITION
Deficiency diseases in India. Diet and incidence of disease. Partial degrees of vitamin insufficiency. National ill health. The death-rate and national health. Effects of improved diets. Chief faults of British diets. Prevention of disease by diet. Maternal mortality. Building an Al nation. Education. Conclusion.
ILLUSTRATIONS
When I accepted the invitation of the Royal
Society of Arts to deliver the Cantor Lectures--an invitation
by which I was greatly honoured--it was my intention to speak
on the more general aspects of nutrition in relation to public
health. But during the time that has elapsed since then I have
seen, heard and read much both in the lay Press and elsewhere
which leads me to believe that the significance of the term, 'nutrition',
is not always fully understood. It has seemed to me desirable,
therefore, to attempt an explanation of it, for if its meaning
be clearly comprehended, its importance to the national health
will become self-evident. This explanation must of necessity deal
with fundamentals, familiar possibly to many of you. But there
may be others of my audience, or who may read these lectures in
their published form, whose understanding of nutrition is less
complete: to these I especially address myself.
It is not possible to comprehend the relationship
of food to nutrition, and of both to health and disease without
some understanding of the structure of the body, of the functions
of food, of the processes involved in the function of nutrition,
and of the pathological changes brought about in the organs and
tissues of the body by derangements of nutrition consequent on
faulty food.
The Cell
The human body, like the bodies of all plants
and animals, excepting those of a very lowly order, is made up
of countless millions of cells. Each cell is composed of a microscopic
mass of protoplasm enclosed in a delicate membrane and having
a differentiated part--the nucleus. Every cell is a perfect physico-chemical
laboratory, doing specialized work and needing special materials,
both for this work and for the maintenance of its structure and
functions The protoplasm, or essential substance of living cells,
is the physical basis of organic life. Upon it depend all the
vital functions: nutrition, secretion, growth, reproduction, irritability
and motility. It is subject to change or differentiation of the
most varied sort: forming epithelium, bone, muscle, nerves, glands,
organs of special sense, etc. It is a viscid, colloidal material
made up of water (hydrogen and oxygen), carbon, nitrogen, and
a number of other elements in complex and unstable combinations.
The nitrogenous substances, known as proteins, enter largely into
its structure, as do a number of inorganic salts. In addition
to these, the cells contain another indispensable component: a
phosphorized fat called lecithin. This substance facilitates the
absorption of nutriment by the cell, the discharge of such specific
products as it may contribute to the processes of the body as
a whole, and the elimination of the end-products of its chemical
activities.
The nucleus is the directing centre of the functional
activity of the cell. It consists of a network of filaments whose
meshes are filled with a special kind of protein containing phosphorus
(nucleo-protein). Along the course of these filaments there are
granules formed of an iron-containing protein (chromatin). Upon
the integrity of the nucleus and the normal structure of its proteins
depend all the vital processes. Presently we shall see how important
the specific proteins of the nucleus are, how important are the
mineral elements--phosphorus and iron--entering into their composition,
how important is the optimum supply to the cells of all elements
and complexes needed for cellular activity. For the root of the
whole matter of food and nutrition is the nourishment of the cell,
whether it be of bone, epithelium, muscle, gland, nerve or special
sense. The inevitable consequence of its faulty nourishment is
depreciation of its structure and functions--the foundation upon
which a vast edifice of disease is built.
Food
Man is made up of what he eats. The constituents
of his food are those of which his body is composed. His foodstuffs,
derived from the vegetable and the animal kingdoms, consist, for
the most part, of matter that is living, that was formerly living
or that is derived from matter that was formerly living. Man cannot
himself build up living tissue from materials which have in themselves
no necessary connection with living protoplasm. This, plants do
for him. Out of the earth and air, and under the influence of
the sun, they transmute certain inorganic substances--mineral
salts, water and carbon dioxide--into organic foodstuffs suited
to his use and to the use of the animals whose produce or whose
flesh he uses as food. He is, indeed, created out of the earth;
and according as the earth provides, by way of plant and animal
life, the materials needed by his body, so is that body well,
ill or indifferently made and sustained.
Food may be defined as anything which when taken
into the alimentary tract provides on digestion materials for
the nourishment of the body; materials wherewith its cells fashion
themselves each after its kind; materials to sustain their structure
and to co-ordinate and control their functions; materials wherewith
tissues of specialized functions elaborate their products; and
materials to provide energy for cellular work.
The substances wherewith these purposes are
effected are oxygen, water and the digestion products of proteins,
fats, carbohydrates, inorganic elements and vitamins. Apart from
oxygen and water, those at present known to be indispensable to
the performance of the body's functions are thirty-six in number.
Of these eighteen are amino-acids, derived from the proteins of
the food. Eleven are inorganic elements: sodium, potassium, calcium,
magnesium, phosphorus, iron, copper, sulphur, manganese, chlorine
and iodine. One is glucose, derived chiefly from carbohydrates
(though the body can in certain circumstances convert proteins
and fats into glucose}. One is linoleic acid, derived from fats.
And five are vitamins: called respectively vitamins A, B, C, D
and E.
No single foodstuff contains all these essentials.
A properly constituted diet is such a combination of foodstuffs
as does provide them all in proper quantity and proportion one
to another. Their proportion, or balance, is a matter of great
importance. We may, indeed, conceive of a properly constituted
diet as a system of mutually adapted parts working together; absence
or inadequacy of one part deranging the whole system. It may be
said of the essential constituents of food, as Marcus Aurelius
has said of other things: 'Meditate often upon the connection
of these things and upon the mutual relation that they have one
unto another. For all are, after a sort, folded and involved one
within another and by these means all agree well together.'
In addition to proteins, carbohydrates, fats,
mineral salts and vitamins, there are in food blood-forming substances,
extractives, flavouring matter and pigments that have parts of
greater or lesser importance to play in the nourishment of the
body. The food must also contain a certain amount of innocuous,
indigestible material, or roughage as it is called, to stimulate
intestinal movements. Besides all this, there is something in
the freshness of food, especially vegetable food--some form of
energy perhaps; it may be certain rays of light or electrical
property--which gives to it a health-promoting influence. Certain
it is that no synthetic diet that I have been able to devise has
equalled in health-sustaining qualities one composed of the fresh
foodstuffs as nature provides them.
Further, the quality of vegetable foods depends
on the manner of their cultivation: on conditions of soil, manure,
rainfall, irrigation. Thus, we found in India that foodstuffs
grown on soil manured with farmyard manure were of higher nutritive
quality than those grown on the same soil when manured with chemical
manure. Rice grown in standing water--the common practice in India--was
less nutritious than when grown on the same soil under conditions
of natural rainfall. Spinach grown in a well-tended and manured
kitchen-garden was richer in vitamin C than that grown in an ill-tended
and inadequately manured one. Examples of this kind might be multiplied,
but these suffice to indicate ways in which agricultural practice
is linked with the quality of food, with nutrition and with health.
If, indeed, man is to derive all the benefits that the soil is
so ready to yield to him, he must employ his intelligence and
his knowledge in rendering it fit to yield them to him. Impoverishment
of the soil leads to a whole train of evils: pasture of poor quality;
poor quality of the stock raised upon it; poor quality of the
foodstuffs they provide for man; poor quality of the vegetable
foods that he cultivates for himself; and, faulty nutrition with
resultant disease in both man and beast. Out of the earth are
we and the plants and animals that feed us created, and to the
earth we must return the things whereof we and they are made if
it is to yield again foods of a quality suited to our needs. Man's
dependence on the earth is beautifully expressed by Robert Bridges
when he says:
From Universal Mind the first-born atoms draw
their function, whose rich chemistry the plants transmute
to make organic life, whereon animals feed
to fashion sight and sense and give service to man,
who sprung from them is conscient in his last degree
of ministry unto God, the Universal Mind,
whither an effect returneth whence it first began.*
*From The Testament of Beauty,
by Robert Bridges Press, Oxford).
Nutrition
Nutrition is the act or process--it is, in fact,
the series of co-ordinated processes--whereby the nourishment
of the body is effected. It consists in the taking-in and assimilation
through chemical changes (metabolism) of materials with which
the tissues of the body are built up and their waste repaired,
by which the processes of the body are regulated, from which energy
is liberated for the work the body has to do, and heat generated
for the maintenance of its temperature. Nutrition is thus a fundamental
function of the body. By the activity proper to it the structural
integrity and functional efficiency of every cell is maintained.
This, indeed, is its primary purpose; for if the mechanism of
the body be perfect, and continue in perfection, it may be trusted
to produce the energy needed for its work provided it be constantly
supplied with suitable fuel. It is the mechanism that matters;
the fuel (or Calories) is merely a question of the energy the
body expends in the maintenance of vital processes--respiration,
circulation, secretion, etc.--and in external (muscular) work.
The processes involved in the function of nutrition
are mastication, deglutition, digestion, absorption, circulation,
assimilation and excretion; the last including perspiration, exhalation,
urinary excretion and defaecation There are thus three stages
in nutrition: the first, effected in and by the alimentary tract;
the second, in or by the cells composing the body; and, the third
by the organs of excretory function--skin, lungs, kidneys and
bowel. It is of the utmost importance to realize that not only
is the activity proper to the function of nutrition dependent
on the efficient performance of all these acts, but their efficient
performance is dependent on the adequate nourishment and functional
efficiency of the organs and tissues performing them.
At this point, and to maintain the sequence
of our story, reference might be made to the implications of these
acts: mastication, digestion, absorption, assimilation, and so
on. But it may be enough to remind you that they include the ordered
operation of involuntary muscular action, the production of various
digestive and other juices, the elaboration of ferments, or enzymes,
and of catalytic agents needed for the speeding-up of chemical
processes, the production of blood-forming substances, the interchange
of body fluids, the transport of nutrients to the remotest recesses
of the body, the removal of end-products of chemical action and
of waste products from the body, and many other vital processes,
all of which are influenced favourably or unfavourably by the
constitution of the food. The alimentary tract and the organs
(including the teeth) associated with it are of particular importance
in this connection. They form a highly specialized mechanism designed
for the nourishment of the body. The efficiency of the function
of nutrition depends primarly on the functional efficiency of
this mechanism and this, in its turn, on the constitution of the
food.
Let me here draw your attention to some of the
tasks which this mechanism has to perform. It splits up, by digestion,
the foodstuffs in such a way that the essential nutrients are
readily absorbed and made available to the cells in forms best
suited to their use. Thus, the many and differing kinds of proteins,
present in the plant and animal tissues we use as food, are all
decomposed into fragments: the amino-acids to which previous reference
has been made. From these fragments, on their absorption, the
body builds up the proteins suited to it and to its different
parts; for each part its special kind. Mark then, how important
it is that the ingested proteins are of kinds that will furnish
all the fragments needed. Similarly, the many kinds of carbohydrates--starches,
sugars, cellulose--in food are all converted into glucose which
is the chief fuel needed for the production of energy, muscular
work and the maintenance of the temperature of the body. Likewise,
the many kinds of fats, each containing different fatty acids,
are converted by digestive processes into soluble soaps which
pass readily through the intestinal wall and in their passage
are re-converted into the fats needed by the body. The mineral
ingredients of food are not only made avallable for use by the
body but the intestinal canal itself regulates to a considerable
extent their absorption and excretion. Each part of this mechanism
has its own contribution to make to the furtherance of the function
of nutrition. Thus, the stomach, in normal conditions, not only
produces the acid and enzymes needed for gastric digestion but,
by its normal contractions, it sustains the appetite for food.
It produces, too, a substance which, by its combination with a
material or materials of unknown nature contained in certain foodstuffs,
gives rise to a product having the specific property of ensuring
the normal formation of the red cells of the blood. Absence of
one or other of the component parts of this product--that produced
in the stomach or that provided in certain foodstuffs--leads to
the occurrence of pernicious anaemia. This product is stored in
the liver for use as required by the bone-marrow--the birthplace
of the red blood cells--hence the use of liver extract for the
cure of this disease. The stomach produces yet another substance
which is necessary for the normal nutrition of the central nervous
system. Thus early in the process of digestion is the welfare
of these two most important tissues--blood and nerve--taken care
of, and by the stomach.
Beyond the stomach, in the duodenum, there are
glands that not only secrete digestive juices but some that produce
protective substances lest the acid contents of the stomach should,
after they leave it, erode the mucous membrane of the bowel. The
continued production of these alkaline and other protective substances
is an important factor in the prevention of duodenal ulcer; and
the continued functional efficiency of the glandular cells producing
them is dependent on the quality of the food. There is no stage
in the whole process of digestion, absorption and passage of the
gastro-intestinal contents along their appointed way which is
not regulated and controlled by some substance or substances derived
from food. Even the time-table of events, which normally proceeds
with clockwork regularity, is under such control. It cannot be
too insistently stated that disturbance of these processes, disturbance
of this time-table, and alterations in form or consistency of
the faecal residues are signs that something is going wrong or
has gone wrong with the function of nutrition.
The alimentary tract is very prone to suffer
both structurally and functionally in consequence of faulty food
and to become the prey of pathogenic agents of disease or the
harbourer of parasites. Further, states of ill health of this
tract often provide conditions precedent to the development of
diseases of faulty nutrition. In such circumstances essential
constituents of food may not be absorbed in sufficient quantity
for the needs of organs and parts of the body, and disease due
to their deficiency may arise. Many years ago (1918), when the
newer knowledge of nutrition was in its infancy, I obtained some
dozens of healthy monkeys from the jungles of Madras. Some I fed
on faulty and ill-balanced food deficient in vitamins and mineral
elements, others on perfectly constituted food. The latter remained
in good health; the former developed gastro-intestinal ailments,
ranging from gastritis and ulcer to colitis and dysentery, while
one amongst them had a commencing cancer of the stomach. The passage
of years has not dimmed the recollection of this crucial experiment
nor detracted from the far-reaching importance of the results
yielded by it. Indeed, there is, perhaps, no more significant
fact in regard to the function of nutrition than that this highly
specialized alimentary mechanism on which the nourishment of the
body depends is itself amongst the most susceptible of the structures
of the body to faulty nutrition.
Nutrition is affected adversely by a number
of factors: imperfect oxygenation of the blood and tissues, as
from faulty breathing, lack of fresh air, bad ventilation, overcrowding
and lack of exercise; insufficient rest and want of sleep; overwork
and fatigue; worry and emotional excitement; lack of sunshine;
insufficient Calories for the work the body has to do; excessive
consumption of alcohol; indigestible food; gastrointestinal disorder;
and' many conditions of ill health. But by far the most important
factor is food of improper constitution. The determination of
the constitution of the food is the first essential in the assessment
of the efficiency or lack of efficiency of the function of nutrition;
the correction of food-faults is the first essential in the restoration
of this function to normal.
Disorder of the function of nutrition, brought
about by faulty food, causes the body to react in a variety of
ways, depending on the nature of the food-faults that give rise
to it, the part or parts of the body effected by it, and the intervention
or the non-intervention of toxic or microbic agents of disease.
These reactions, involving as they do disturbance in structure
or in functions of various parts of the body, manifest themselves
as subnormal states of health or as actual disease in great variety
of form.
It will be realized from these considerations
how far-reaching are the aspects of nutrition. They include the
chemistry of food, the chemical changes (metabolism) whereby the
function of nutrition is effected, the activity of the various
organs and tissues in response to food conditions, the structural
and functional changes induced in organs and tissues by faulty
food, and the conditions of the body that result from faulty nutrition.
Nutrition touches upon, indeed embraces in its compass, many subdivisions
of biology--big-chemistry, big-physics, morphology, physiology,
pathology and medicine. Knowledge of it helps to bridge the gulf
between physiology and pathology--a gulf in need of bridging--it
is, indeed, an essential foundation of rational medicine.
Nutrition is commonly spoken of as a condition
of body--excellent, normal or subnormal, as the case may be--when,
in truth it is a function of the body on which condition of body--i.e.
health--depends. For a proper comprehension of nutrition and of
the processes involved in it this distinction has to be borne
in mind. Such terms as under-nutrition and malnutrition are nowadays
in common use, often without a clear conception of their meaning.
Sometimes they are used to signify a condition of body which under-nourished
would more fittingly describe; sometimes to signify under-feeding.
'Malnutrition', we are reminded by Fowler in his Modern English
Usage, 'is a term to be avoided as often as under-feeding will
do the work', for malnutrition is not merely underfeeding but
disorder of the processes of nutrition brought about, as a rule,
by the habitual use of food of improper quality.
Nutrition is, also, commonly defined as 'food',
'nourishment', 'that which nourishes'. But, as we have just seen,
it is something much more than this. Food is the instrument, nutrition
is the act of using it. To employ the term 'nutrition' as an alternative
one for 'food' is to miss its true meaning, to fall in comprehending
not only that in which nutrition consists, but all that is meant
by its derangements.
Health
Health is variously defined as 'soundness of
body', 'state of bodily or mental well-being', 'freedom from disease,
disorder, pain or weakness'. It is, in fact, a variable condition
of body as in good, bad, poor or ill health. At its best it is
'that state of being in which all the parts and organs are sound
and in proper condition; that condition of the body and its various
parts and functions which conduces to efficient and prolonged
life. It implies, moreover, the ability to produce and rear offspring
fitted to live and efficiently to perform the ordinary functions
of their species'.* This optimum state of being can be attained
when--but only when--the animal organism is adequately nourished.
Further, it is possible to produce at will in animals under experimental
conditions every grade of health--good, bad or indifferent--by
alterations in the composition of their diets. Specific diseases
of many kinds can be produced by feeding them on diets having
specific food-faults or prevented by the correction of these faults.
The interaction of faulty food, faulty nutrition and microbic
or toxic agents leads to the spontaneous appearance of many others
or to their controlled appearance at the will of the experimenter.
I know of nothing so potent in maintaining good health in laboratory
animals as perfectly constituted food; I know of nothing so potent
in producing ill health as improperly constituted food. This,
too, is the experience of stockbreeders. Is man an exception to
a rule so universally applicable to the higher animals? It seems
most unlikely that he can be, although it is to be recognized
that his requirements for adequate nutrition, and the effects
upon him of deficiencies of various food-essentials, are not necessarily
the same as in animals. Indeed, these effects are known to differ
in different species of animals. Nevertheless, the principles
of nutrition are fundamentally the same in man and in animals.
It may, therefore, be taken as a law of life, infringement of
which will surely bring its own penalties, that the greatest single
factor in the acquisition and maintenance of good health is perfectly
constituted food. It is this thesis that I have to sustain in
these lectures.
*Century Dictionary.
The Experimental Method in Research on Nutrition
As you are probably aware, it is customary in
the investigation of nutritional problems in the laboratory to
use the experimental method and to feed animals rats:, as a rule--on
synthetic diets composed of purified food-materials, but lacking
this or that essential according to the nature of the inquiry
in hand. The results of such experiments, though of great value
in the ascertainment of the function of a given essential of food,
and in the precise determination of the bio-chemical and-pathological
changes resulting from its want, are open to the objections that
the observations made in rats are not necessarily applicable to
human beings, that synthetic diets such as are used in these experiments
are never eaten by human beings, that human diets are rarely or
never wholly lacking in any single food-essential, that their
deficiencies are usually multiple, and, that the diets of mankind
are often unbalanced in other regards, such, for instance, as
in their high content of carbohydrates relative to other food-essentials.
The validity of these objections cannot be gainsaid; nevertheless,
it may be remarked in passing that the frequency with which results
observed in rats are applicable to man is remarkable--a fact which
will be the better appreciated from the examples I am about to
place before you. Further, without such experiments on animals
the vast amount of knowledge revealed by them within recent years
would, for the most part, be hidden from us, and we would still
be in ignorance of the kind of consequences to expect in man from
his continued use of food of faulty constitution. We would, moreover,
be in ignorance of what a properly constituted diet is.
But when in such investigations, diets composed
of food-materials in common use by man or diets in actual use
by human beings are used in the feeding of our animals, most of
these objections do not arise, and the results observed have a
more direct application to man, provided the faulty combinations
of the food-materials entering into the diets are such as uninstructed
man himself commonly employs. It has seemed to me necessary, therefore,
to use in my experimental work diets composed of the actual materials
that human beings eat; and it is with such diets that most of
my work has been done.
Before giving examples of the effects of such
faulty diets on the animal organism, let me draw your attention
to the relation of the national diets of India to the physical
efficiency of the races using them.
Food and Physical Efficiency
Nowhere in the world is the profound effect
of food on physical efficiency more strikingly exemplified than
in India. As you know, India has some 350 million inhabitants,
made up of many races presenting great diversity in their characteristics,
manner of life, customs, religion, food and food- habits. The
tribes of the Indian Frontier, and of Himalayan regions, the Peoples
of the Plains--Sikhs, Rajputs, Mahrattas, Bengalis, Ooriyas, Madrassis,
Kanarese and many others--exhibit, in general, the greatest diversity
of physique. And as each race is wedded to its own manner of living,
to its own national diet, comparison between them is easy.
The level of physical efficiency of Indian races
is, above all else, a matter of food. No other single factor--race,
climate, endemic disease, etc.--has so profound an influence on
their physique, and on their capacity to sustain arduous labour
and prolonged muscular exertion. 'As we pass from the North-West
region of the Punjab down the Gangetic Plain to the coast of Bengal,
there is a gradual fall in the stature, bodyweight, stamina and
efficiency of the people. In accordance with this decline in manly
characteristics it is of the utmost significance that there is
an accompanying gradual fall in the nutritive value of the dietaries.'
So wrote McCay, as a result of his investigations, a quarter of
a century ago. My own observations have served to confirm his
conclusions, though I find other causes in addition to protein-insufficiency--to
which he attached chief importance--for the decline he refers
to. This decline extends also to the peoples of the south and
west of India, being especially apparent in certain parts of the
Madras Presidency. This is not to say that in these parts there
are not many people of good physique nor that in the north of
India there are not many whose physique is poor. But speaking
of the generality of the people, it is true that the physique
of northern races of India is strikingly superior to that of the
southern, eastern, and western races (Fig. 1). This difference
depends almost entirely on the gradually diminishing value of
the food, from the north to the east, south and west of India,
with respect to the amount and quality of its proteins, the quality
of the cereal grains forming the staple article of the diet, the
quality and quantity of the fats, the mineral and vitamin contents,
and the balance of the food as a whole. In addition to these questions
of quality there is the further one of quantity. In regard to
the latter little need be said; for it is obvious that if a man
is not getting enough to eat he cannot be physically efficient.
Unfortunately, the numbers in India who do not get enough to eat
may be counted by the hundred thousand.
Figure 1. Note fine physique of races (Mahratta, Sikh, Pathan) whose diets are well constituted and poor physique of those (Bengali, Madrassi) whose diets are ill-constituted. Note similar effect on rats fed on those diets. From left to right, the rats represent Sikh, Pathan, Mahratta, Goorkha, Kanarese, Bengali, Madrassi.
In general the races of northern India are wheat-eaters,
though they make use also of certain other whole cereal grains.
Now the biological value of the proteins of whole wheat is relatively
high; and the wheat is eaten whole, after being freshly ground
into a coarse flour (atta) and made into cakes called chapattis.
It thus preserves all the nutrients with which Nature has endowed
it, particularly its proteins, its vitamins and its mineral salts.
The second most important ingredient of their diet is milk, and
the products of milk (clarified butter or ghee, curds, buttermilk;
the third is dhal (pulse); the fourth, vegetables and fruit.
Some eat meat sparingly, if at all; others, such as the Pathans,
use it in considerable quantity. Their food thus contains--when
they can get the food they want, which they do not always do--all
elements and complexes needed for normal nutrition (with the possible
exception of iodine in some Himalayan regions) and abundance of
those things that matter from the point of view of the structural
and functional efficiency of the body. In conformity with the
constitution of their dietaries they are the finest races of India,
so far as physique is concerned, and amongst the finest races
of mankind. Familiar as I am with the chapatti-fed races of northern
India, I have little patience with those who would have us believe
that 'white flour' is as good an article of diet as 'whole wheat
flour'. White flour, when used as the staple article of diet,
places its users on the same level as the rice-eaters of the south
and east of India. They are faced with the same problem; they
start to build up their dietaries with a staple of relatively
low nutritive value. If their health and physical fitness are
not to suffer, they must spend more money on supplementary articles
of diet in order to make good the deficiencies of white flour
than if they had begun to build on the surer foundation of whole
wheat flour (Fig 2). So it is with rice, which is the staple article
of diet of about ninety millions of India's inhabitants. The rice--a
relatively poor cereal at best--is subjected to a number of processes
before use by the consumer; all of which reduce--some to a dangerous
degree--its already sparse supply of certain essential nutrients.
It is parboiled, milled or polished; often all three. It is washed
in many changes of water and, finally, it is boiled. It is thus
deprived of much of its proteins and mineral salts and of almost
all its vitamins. Add to this that the average Bengali or Madrassi
uses relatively little milk or milk-products, that by religion
he is often a non-meat-eater, that his consumption of protein,
whether of vegetable or of animal origin, is, in general, very
low, that fresh vegetable and fruit enter into his dietary but
sparingly, and we have not far to seek for the poor' physique
that, in general, characterizes him. In short, it may be said
that according as the quality of the diet diminishes with respect
to proteins, fats, minerals and vitamins, so do physical efficiency
and health; a rule which applies with equal force to the European
as to the Indian.
Figure 2. White flour versus while wheat flour, showing individual weight curves of young rats fed on white flour or whole wheat flour alone or in combination with butter or yeast or both.
The arrows indicate day of death (usually from pneumonia). Note high mortality in rats fed on white flour diets: 30 per cent as compared with 4 per cent in those fed on whole wheat flour diets.Note (1). Whole wheat flour is more suitably constituted to sustain well-being for short periods than white flour when the sole article of food.
Note (2). The addition of butter to a white flour diet improves it but slightly; whole wheat flour and butter is a better diet than white flour and butter.
Note (3). The addition of 5 per cent yeast to a diet of white flour improves the rate of growth but the animals are very prone to pneumonia due to want of Vitamin A.
Relative Values of National Diets of
India
This truth will probably be best appreciated
by a reference to an experiment carried out in my laboratory some
years ago, with the object of determining the relative values
of certain national diets of India: Albino rats were employed
in this test. The cycle of development in the rat takes place
about thirty times as quickly as in man, so that the experiment
about to be described, which lasted 140 days, would correspond
to the observation of human beings, under the same experimental
conditions, for a period of nearly twelve years. Seven groups
of twenty young rats, of the same age, sex-distribution and bodyweight,
were confined in large, roomy cages under precisely similar conditions
of life. To one group the diet as prepared and cooked by the Sikhs,
was given; to another that of the Pathans; to a third that of
the Mahrattas; and so on through Goorkhas, Bengalis, and Kanarese
to Madrassis. The results on the eightieth day of the experiment
are shown in Fig. 1; from which it will be seen that the various
diets ranged themselves in the following descending order of nutritive
value: Sikh, Pathan, Maharatta, Goorkha, Kanarese, Bengali and
Madrassi. At the end of 140 days the animals in each group were
weighed and an average taken of their aggregate weight. The rat
which conformed most closely to the average for its particular
group was photographed side by side with the average rats from
other groups. The photograph shown in Fig. 1 is the result. From
it we see that it conforms to the results of observations made
in man himself. In brief, the best diet--that of the Sikhs--contains
in abundance every element and complex needed for normal nutrition,
the worst diet--that of the Madrassi--has many faults: it is excessively
rich in carbohydrates, and deficient in suitable protein, mineral
salts and vitamins. Presently we shall see that this difference
in the nutritive value of these diets is reflected in the diseases
from which the people of the north and south of India suffer.
Freedom of Well-Fed Animals from Disease
So impressed was I by the adequacy of the northern
Indian's diet that during the later years of my experimental work
I used it as the diet of my stock rats. These numbered about 1,000.
Their food consisted of chapittis lightly smeared with
fresh butter, sprouted Bengal gram (pulse), raw, fresh
vegetables (cabbage and carrots) ad libitum, milk, the hard crusts
of bread (to keep their teeth in order), a small ration of meat
with bone once a week, and water. They were kept in stock for
about two years--a period approximately equal to the first fifty
years in the life of a human being--the young being taken as required
for experimental purposes, and the remainder used for breeding.
During the five years prior to my leaving India there was in this
stock no case of illness, no death from natural causes, no maternal
mortality, no infantile mortality. It is true that the hygienic
conditions under which they lived were ideal, that they were comfortably
bedded in clean straw, that they enjoyed dally exposures to the
sun practically the whole year round, and that the care bestowed
upon them was great; but the same care was bestowed during these
years on several thousand deficiently-fed rats, which developed
a wide variety of ailments (vide infra) while the well-fed
animals enjoyed a remarkable freedom from disease. It is clear,
therefore, that it was to their food that this freedom was due.
If man himself did not provide in his own person the proof that
a diet composed of whole cereal grains, or a mixture of cereal
grains, milk, milk-products, pulses and vegetables, with meat
occasionally, sufficed for optimum physical efficiency, this experience
in rats would do so. It is not, therefore, unreasonable to conclude
that if by minute attention to three things--cleanliness, comfort
and food--it is possible to exclude disease from a colony of cloistered
rats, it is possible greatly to reduce its incidence by the same
means in human beings and to produce a race whose physique is
as nearly perfect as nature intended it to be.
Supposing now we cut out the milk component
of this diet or reduce it to a minimum, we find that disease soon
begins to make its appearance, especially if at the same time
we limit the consumption of fresh vegetable foods. I have repeatedly
made these restrictions with the result that respiratory diseases,
gastro-intestinal diseases and maladies consequent on degenerative
changes in mucous membranes and other structures of the body become
frequent. It is apparent, therefore, that the diet of the Sikhs
is only health-promoting so long as it is consumed in its entirety.
Indeed, we know that those of this race who, for whatever reason,
do not consume adequate quantities of milk, milk products and
fresh vegetables, do not long retain the fine physique for which
the Sikhs are famous. These food-materials are for them and in
their own parlance, takatwar khurak (foods that give strength);
nowadays we speak of them as 'the protective foods', since they
make good the deficiencies of muscle meat, refined cereals, etc.,
which enter so largely into the diets of western peoples.
Before leaving this experience, let me emphasize
two things: the first, that all things needful for adequate nourishment
of the body and for physical efficiency are present in whole cereal
grains, milk, milk-products, legumes, root and leafy vegetables
and fruits, with egg or meat occasionally. What is eaten besides
these is more a matter of taste than of necessity. And the second:
that the diet must be complete in every essential. It is not to
be expected that by substituting, for instance, wholemeal bread
for white bread, health will benefit greatly unless the substitution
completely restores the balance of an ill-balanced diet, nor that
by adding bottled vitamins or mineral elements to a faulty diet
its faults will be remedied, unless they be confined to vitamins
or mineral elements. The correction of food faults lies first
in their computation and thereafter in the construction of a diet
so balanced and complete as to satisfy all physiological needs.
Fortunately, the layman need not concern himself with such computations,
though in institutions they may be necessary. It suffices for
him to know that in whole cereal grains, milk, milk products,
eggs and fresh vegetables he has foods that, when used in adequate
quantities, will maintain the structural integrity and functional
efficiency of his body.
A Good Diet and a Bad One: A Comparative Study
Consider now another experiment, also in rats
(Fig. 3). Two identical groups, twenty in each, from the above-mentioned
stock were used in it. They were housed in colonies: both in large
cages of the same dimensions. One group was fed on a diet similar
to that used by the Sikhs; the other on a diet such as is commonly
used by the poorer classes in England. The latter diet consisted
of white bread, margarine, over-sweetened tea with a little milk
(of which the rats consumed large quantities) boiled cabbage and
boiled potato, tinned meat and tinned jam of the cheaper sorts.
It has many faults, of which vitamin and mineral deficiencies
are the chief. The first thing one noticed, as this experiment
progressed, was that the members of the former, and well-fed,
group lived happily together. They increased in weight and flourished.
The other group did not increase in weight; their growth was stunted;
they were badly proportioned; their coats were staring and lacking
in gloss; they were nervous and apt to bite the attendants; they
lived unhappily together and by the sixtieth day of the experiment
they began to kill and eat the weaker ones amongst them. When
they had disposed of three in this way I was compelled to segregate
the remainder. The experiment was continued for 187 days, or for
a period which would correspond to about sixteen years in man.
During this period three animals in the former group died--one
(a pregnant animal) from an abdominal injury, one from an undiscovered
cause, and one from pneumonia. In the latter group six died of
pneumonia and three were killed by their fellows. The survivors
in both groups were killed and subjected to post-mortem examination.
The outstanding differences in the incidence of disease in the
two groups were these: disease of the lungs was much commoner
in the group fed on the poorer class Britisher' s diet; gastro-intestinal
disease (gastritis, gastric congestion, outgrowths of epithelium
in the stomach, and intestinal stasis) was frequent in this group,
while that receiving the Sikh diet was free from it. Indeed, the
animals fed on the poorer class Britisher's diet fared little
or no better than those, in another experiment, that were fed
on a diet in common use in Madras, and the maladies from which
they suffered were much the same. The results of this experiment
indicated clearly that a diet, such as is commonly used by the
poorer classes in England, gives rise in rats to two chief classes
of ailment--pulmonary and gastrointestinal--while a more perfectly
constituted diet, such as is commonly used by northern Indian
races, affords a considerable measure of protection against both.
It is not unreasonable, therefore, to expect that, other things
being equal, similar results will arise in man from the use of
these diets. We do, in fact, find that these two classes of ailment
are amongst the most frequent of the maladies afflicting the poorer
class Britisher (Fig. 5) as well as the poorer class Madrassi.
Food and Peptic Ulcer
Another example may be provided by peptic ulcer
(gastric and duodenal). This malady is very common in the south
of India, rare in the north. It is, in fact, fifty-eight times
more common in the latter part of India; it is particularly so
in Travancore. In order to determine whether or not it was related
in its genesis to diet the following experiment was undertaken.
Three groups of young rats, from the healthy stock above referred
to, were fed as follows: one on the well-constituted diet as used
by the Sikhs, but reinforced with additional milk; one on the
carbohydrate-rich, protein-poor, vitamin-poor and mineral-poor
diet in common use by the poorer class Madrassi; and the third
on the diet--largely made up of tapioca--in common use by the
poorer classes in Travancore, amongst whom peptic ulcer is so
common. This diet has many faults, of which protein, mineral and
vitamin deficiencies are the chief. The experiment was continued
for close on 700 days, a period which would correspond to about
fifty years in man. Many animals in the last two groups died during
its course, from the usual respiratory and gastrointestinal diseases.
The results revealed at post-mortem examination of all the animals
were, as far as peptic ulcer was concerned, as follows: first
group (Sikh diet), nil, second group (Madrassi diet), 11 per cent;
third group (Travancore diet), 29 per cent incidence of peptic
ulcer.
Here, again, we see that a disease common in
certain parts of India (as it is in this country) can be produced
in rats by feeding them on the faulty diets in common use by the
people of these parts, while other animals, fed on a perfectly
constituted diet in common use by human beings, amongst whom peptic
ulcer is rare, remain free from it. Surely, if we are to place
any reliance on animal experiments of this kind, we must regard
faulty and ill-balanced food as a cause of gastric and duodenal
ulcer in human beings? How it causes it, whether by direct or
indirect action or want of action, or because of want of this
or that essential of food or excess of this or that one, is a
matter of little consequence--though of much scientific interest.
What is of consequence, not only to the people of India, but,
I venture to affirm, to the people of this country, is that by
the continued use of a perfectly constituted diet they are unlikely
to develop gastric or duodenal ulcer.
Experimental Beri-Beri and 'Stone'
Examples of this kind, occurring in my own experience,
might be multiplied to an extent that would occupy many hours
in their narration. I must, therefore, limit their numbers. Two
will suffice: As no doubt you all know there is a disease called
beri-beri, which is prevalent in certain parts of the tropics,
chiefly amongst rice-eaters. It is not prevalent amongst rice-eaters
in other parts of India, nor is it so prevalent in its endemic
homes as a comparatively recent broadcast by the B.B.C. may have
led some of you to suppose: every other woman in the south of
India does not suffer from beri-beri. About forty years
ago Eijkman noticed that if fowls were fed on an exclusive diet
of polished rice they developed a type of polyneuritis which had
certain likenesses to beri-beri--a malady in which polyneuritis
is a prominent symptom. He found, moreover, that they did not
develop this 'nutritional polyneuritis'--as he rightly called
it--when they were fed on unpolished rice or on polished rice
to which the rice-polishings were added. So he, and his colleague,
Grijus, concluded that there was something--vitamin B1
as it ultimately proved to be--in the rice-polishings which prevented
the nutritional polyneuritis in birds, a something that might
possibly prevent beri-beri in man, as indeed it (vitamin B1) is now known to do. But to prevent is one
thing, to cause, if the preventive be removed, is, or may be,
another. It is nowadays an almost universal belief that on a diet
of polished rice or on a diet devoid of vitamin B1
beri-beri develops after a few months. Theoretically, this is
possible, in practice it is a rare occurrence. For no one, even
in localities where beri-beri is endemic, ever does live on an
exclusive diet of polished rice or on a diet devoid of vitamin
B1 always the diet contains some of this
factor, however little that may be. Further, only a relatively
small proportion of persons subsisting on diets deficient in vitamin
B1 do develop beriberi, even in endemic
areas of the disease. If one feeds pigeons on a diet almost devoid
of this vitamin they develop polyneuritis, but polyneuritis is
only one of the symptoms of human beri-beri; there are two others,
equally important grave disorder of the heart and oedema. Now
supposing one does, as I have often done, feed pigeons on diets
similar to those in actual use by human sufferers from beri-beri,
then we find that a disease having all the pathological characters
of true beri-beri does develop in a proportion of the birds, just
as it does in a proportion of human beings. But this diet is not
devoid of vitamin B1, although it is low
in it. It does not contain enough of it to prevent the disease,
or enough of some other factor in addition to vitamin B1,
to prevent the development of the complete syndrome, or, alternatively,
to prevent the development or operation of the ultimate causal
agents of the malady. Now if in such a diet one substitutes whole
wheat flour for a part of the rice and at the same time we add
to it fresh vegetables, such as tomatoes, then the disease does
not arise, either in birds or in man. I have, myself, so prevented
human beri-beri in a certain gaol in the East where it was wont
to break out year after year; and many others, since the days
of Takaki--who first prevented it in the Japanese Navy as long
ago as 1882--have by similar means prevented it. This is another
example of the control that the use, in animal experiments, of
human diets may exercise over results reached by the use of a
single component of them, such as polished rice.
We have seen that if rats be fed on the perfectly
constituted diet of the Sikhs they remain in good health: they
do not, for instance, develop stone in the urinary tract. But
if one removes from this diet the milk and milk products and cuts
down the fresh vegetable foods to a minimum, then many of them
do develop this condition. They develop also a wide variety of
other ailments, but it is with 'stone' that I am here concerned.
If we replace the milk or butter they do not develop this condition.
This is an observation of great importance to the wheat-eating
races of northern India, amongst whom 'stone' is so common. For
it is precisely these articles of diet--milk, milk products and
fresh vegetables--which the poorer classes amongst them have to
cut out when times are hard. There are, no doubt, other factors
concerned in the causation of 'stone'; but the broad fact remains
that a perfectly constituted diet rich in milk, milk products
and fresh vegetable foods affords a high degree of protection
against it.
Variety of Disease in Improperly Fed Animals
I have mentioned the freedom from disease enjoyed
by well-fed and hygienically housed albino rats. During the last
eighteen years of my experimental work in India I used many thousands
of animals--rats, pigeons, fowls, rabbits, guinea-pigs and monkeys--feeding
them on diets not synthetically prepared from purified foodstuffs
but from foodstuffs in common use by the people of India; my purpose,
as previously hinted, being to learn what relation the food used
by the people had to the diseases from which they suffered. At
the risk of being tedious I shall now enumerate the maladies I
have encountered in these improperly-fed animals, leaving out
of count such manifestations of ill health as weakness, lassitude,
irritability and the like, which are commonly met with in malnourished
animals. Here is the list. Skin diseases: loss of hair,
gangrene of the feet and tail, dermatitis, ulcers, abscesses,
oedema. Diseases of the eye: conjunctivitis, corneal ulceration,
xerophthalmia, panophthalmitis, cataract. Diseases of the ear:
otitis media, pus in the middle ear. Diseases of the nose:
rhinitis, sinusitis. Diseases of the lungs and respiratory
passages: adenoids, pneumonia, broncho-pneumonia, bronchiectasis,
pleurisy, pyothorax, haemothorax. Diseases of the alimentary
tract: dental disease, dilatation of the stomach, gastric
ulcer, epithelial new growths in the stomach (two cases of cancer),
duodenal ulcer, duodenitis, enteritis, colitis, stasis, intussusception
and a condition of the lower bowel suggestive of a pre-cancerous
state. Diseases of the urinary tract: pyonephrosis, hydronephrosis,
pyelitis, renal calculus, nephritis, urethral calculus, dilated
ureters, vesical calculus, cystitis! incrusted cystitis. Diseases
of the reproductive system: endometritis, ovaritis, death
of the foetus in utero, premature birth, uterine haemorrhage testicular
disease. Diseases of the blood: anaemia, a pernicious type
of anaemia, Bartonella muris anaemia. Diseases of the lymph
and other glands: cysts, abscesses, enlarged glands. Disease
of the endocrine glands: goitre, lymph-adenoid goitre, adrenal
hypertrophy, atrophy of the thymus, haemorrhagic pancreatitis
(very occasionally). Diseases of the heart: cardiac atrophy,
cardiac hypertrophy, myocarditis, pericarditis, hydropericardium.
Diseases of the nervous system: polyneuritis, beri-beri,
degenerative lesions. Diseases of bone: crooked spine,
distorted vertebrae (no work was done on rickets--a known 'deficiency
disease'). General diseases: malnutritional edema, scurvy,
prescorbutic states.
All these conditions of body, these states of
ill health, had a common causation: faulty nutrition, with or
without infection. They are the clinical evidence--the signs and
symptoms--of the structural and functional changes in organs or
parts of the body that result directly or indirectly from faulty
nutrition. It will be noted that local infections and maladies
of a chronic and degenerative kind are conspicuous amongst them.
These maladies are, in short, the symptoms of malnutrition as
observed in animals fed on faulty diets--some of them admittedly
very faulty--in use by human beings, or on food-materials in use
by them. It is reasonable, then, to expect that maladies of a
similar order are likely to result from malnutrition in human
beings. In my next lecture I shall endeavour to make clear how
it is that food of improper constitution leads to that disturbance
of structure or function of organs or parts of the body which
is 'disease'.
In my first lecture
I confined myself to the more general aspects of the relation
of food to nutrition and of both to health and disease. To-day
I propose to deal in more detail with those essentials that are
needed for the efficient construction and maintenance of the fabric
of the body and for the regulation of its processes. It is necessary
to be aware of the different parts these substances have to play
in nutrition and of the effects of their inadequate supply or
inadequate utilization when supplied in sufficient quantities.
For then only can it be understood how such inadequacy leads to
that disturbance of structure or function of organs or parts of
the body which is 'disease'.
These essentials are proteins, mineral elements
and vitamins. But before dealing with them something must be said
of oxygen and water.
Oxygen and Water
Strictly speaking both oxygen and water are
to be regarded as foods, for of all the supplies on which the
cells of the body are dependent they are the chief. The
continued and unhampered supply of oxygen--avallable in
the air we breathe--is, as you know, essential to the continued
activities of the body. Respiration depends upon it; tissue-respiration
as well as respiration in its commonly understood sense. So also
does combustion, both of organic materials ingested as food and
of certain substances that result from cellular activity. By its
means the latent chemical energy of food is converted into other
forms of energy for the work--both internal and external--of the
body, and the waste products of that work are burned up and disposed
of. Thus, the non-volatile substance--lactic acid--produced during
muscular work, is burned to the volatile carbonic acid which is
carried away by the blood and exhaled through the lungs. Without
the adequate supply of oxygen the body would become clogged by
the accumulation of waste. It is not possible here to discuss
the manifold activities of oxygen in the body nor, indeed, is
it necessary to do so. It suffices to emphasize the great importance
of the efficient oxygenation of the tissues in maintaining the
efficiency of the function of nutrition. The proper ventilation
of the lungs and the proper exercise of the body are obvious means
to this end. These means are complemental to the use of properly
constituted food on which, also, the adequate supply of oxygen
to the tissues depends.
Water is of outstanding importance to
the body, both from the point of view of structure and of function.
It is the most abundant constituent of living cells. Its presence
therein permits of changes in their form and of their return to
their original form after alteration by movements; rapid displacements
of substance and the mobility of living matter are thus rendered
possible. Its conservation of the boundaries of ceils and their
restoration after displacements due to motion conserve in their
turn the minute internal structure of cells.
Although about two-thirds of the fabric of the
body are made up of water, it is not present in all tissues in
the same amount. Fatty tissue and bone contain less, the grey
matter of the brain, glandular organs and muscle contain more,
and the body fluids (blood, etc.) most. The percentage of water
is highest in those tissues wherein chemical changes are most
rapid, and in tissues that are called upon to function most frequently.
The great importance of an adequate supply of water for infants
and growing children, in whom metabolic processes are most active,
is thus made evident.
Water is the solvent of most of the constituents
of protoplasm; it is the vehicle that transports nutrients to
the ceils, the medium wherein all chemical changes take place
within them and the solvent wherein the end-products of these
chemical changes are discharged from the body. The evaporation
of water from the lungs and skin is one of the chief factors in
the regulation of body temperature. It has, too, various mechanical
functions such as in facilitating the movements of mobile parts
(for example, joint surfaces and coils of intestine) one upon
another. The functional efficiency of the digestive tract, the
normal production of the digestive juices, the normal absorption
of food and the normal action of the bowels may be cited as conspicuous
examples of the need of the body for an adequate supply of water.
Water is constantly being discharged from the
body by way of the skin (perspiration), lungs (exhalation), kidneys
(urination) and bowel (defaecation). This loss is partly replaced
by the water contained in solid food and by that produced in the
chemical reactions of metabolism. But over and above this more
than a quart, as such or in beverages, is needed dally to make
good the loss. The need of the cells and tissues for water is
expressed in that indefinite sensation which we call 'thirst'.
The first rule in dietetics is to drink water in abundance.
The insufficient ingestion of water gives rise
to headache, loss of appetite, disturbance of digestive functions
and of the action of the bowels, nervousness and impaired capacity
for work, mental or physical. In infants the loss of water consequent
on diarrhoea, vomiting or excessive evaporation from the lungs
may cause serious symptoms: fallure of digestive processes consequent
on diminished production of the digestive juices, rapid loss of
weight, dry skin, exhaustion, coma and convulsions.
Proteins
Proteins are the next most abundant constituents
of living cells. Their chief role in the body is to provide materials
for its growth and for the repair of its tissues. There is a constant
utilization of proteins in these ways, a continual voiding of
the waste products of their metabolism. Their continuous supply
is, therefore, necessary; and this supply must be of the right
kind, to furnish the requisite amino-acids from which the tissues
of various parts of the body are built up. Besides their function
as providers of building-materials they also furnish a certain
amount of energy. They are the source from which the body elaborates
certain enzymes, or ferments, such as those concerned in the digestive
processes, and catalytic agents--glutothione, thyroxine, adrenaline
and insulin--needed for the speeding up of chemical processes.
The daily requirements of the body for proteins
are approximately 1.0 gramme per kilogramme of normal bodyweight;
more than this is an undesirable excess. Sources of them amongst
animal foods are milk, meat, glandular organs, eggs and fish;
and amongst vegetable foods, legumes, whole cereal grains, seeds,
nuts and green vegetables. Those derived from animal sources are,
in general, more suited to the needs of the human body than those
derived from vegetable sources. The former are, in consequence,
sometimes spoken of as 'good', 'suitable' or 'first-class' protein,
and the latter as 'second-class' protein. But it is not necessary
that the protein requirements of the body should be derived chiefly
from animal sources; it suffices if one-third of them be so derived.
Nor is it necessary that 'good' protein be derived from 'meat'.
Those of milk are amongst the best of all proteins and well able
'to leaven the whole lump' of those derived from vegetable foods.
For this reason, amongst others, presently to be referred to,
the use of milk and cheese as articles of diet, should be greatly
extended. Much greater use should also be made of the better class
vegetable proteins, such as those of soya bean, legumes and nuts,
and-much less use of the flesh of animals. Apart from every other
consideration the use of meat as the main source of proteins is
as uneconomical as it is unnecessary; but where flavour is there
will desire be also.
It will be obvious from these considerations
that the insufficient ingestion, absorption or assimilation of
proteins, or of proteins of the right kind, will tend to degradation
of vital processes; a degradation manifested in stunting of growth,
poor physique, lack of energy, resource and initiative, digestive
disturbances and impaired action of glandular organs. To these
there may be added a lowered resistance to infection. Severe degrees
of protein-starvation, associated as they often are with want
of food in general, may give rise to a condition known as 'malnutritional
oedema', 'war oedema' or 'famine oedema' in which the body, in
part or in whole, becomes waterlogged.
Mineral Salts
The mineral constituents of food consist of
some twenty elements of which eleven--previously enumerated (chap.
I)--are definitely known to be essential to vital processes. They
are all intimately related one to another by complex chemical
combinations and interactions, so that it is difficult to separate
the functions of one from those of another. In general these functions
are to provide building materials for the fabric, and to regulate
various functions, of the body. In fulfilment of the first function
some enter into the composition of all cells while others form
the major part of the skeleton and teeth. In fulfilment of their
regulating functions they have various parts to play: all are
concerned in controlling the normal exchanges of body-fluids and
the permeability of the cell membranes; some maintain and regulate
the neutrality of the blood, others the normal contractility of
muscles and excitability of nerves; some enter into the composition
of the digestive juices; others take part in the transport of
oxygen from the lungs to the tissues and of carbon dioxide from
the tissues to the lungs, thus making oxidation processes possible.
Indeed, it may be said that the more the mineral constituents
of food are studied, the more important is their role in nutrition
found to be. It is essential to remember this importance in view
of the prominence which nowadays is given to vitamins--the one
class of substances is as important as the other.
Mineral substances are continually being lost
by the body by way of the excretions, and their replacement is
constantly necessary. Thus, in certain circumstances, the loss
of salt may be excessive and give rise, if not replaced, to distressing
symptoms. Herbivorous animals, and those human beings whose food
is vegetarian, require more salt than carnivore or flesh-eaters.
From the point of view of dietary construction,
four of these mineral elements--calcium, phosphorus, iron and
iodine--are of outstanding importance; not only because of their
own functions but because they are those most likely to be present
in the average diet in insufficient quantities. In constructing
diets the amounts of these minerals should be adjusted with the
same care as is given to those of proteins, carbohydrates, fats
and vitamins; and, in estimating the quantities of essential components
in any diet, the calculations should always include these four
elements. By making provision for their ample supply no serious
deficiency of any other mineral essential is likely to arise.
Calcium.--Calcium is one of the most
important, as well as most widespread, of all constituents of
the body. It is a chief constituent of the bones and of the teeth.
It controls the contractility of muscle including that of involuntary
muscles such as those of the gastro- intestinal tract. The rhythmic
beat of the heart depends to a great extent upon it, as do the
movements of cilia (vide infra). It maintains the normal
response of the nerves to stimuli, preventing their hyper-irritability,
preserves the clotting power of the blood, and sustains the capillary
circulation. It co-ordinates the activities of certain other mineral
elements.
Calcium is made use of in the body to the extent
of about 0.68 gramme daily; but to allow a fair margin for waste
and non-absorption the food should provide at least a gramme a
day. The allowance for expectant mothers and for growing children
should be even greater. The growth of the bones and teeth as well
as of the body generally, menstruation, pregnancy and lactation
make special demands for its abundant supply, more especially
in western countries where sunshine is scanty and the intake of
vitamin D--a substance controlling the absorption and utilization
of calcium--is low.
The insufficient supply of calcium in the food
is one of the commonest of all food-faults in this country. Indeed,
it is difficult for the growing child, under modern conditions
of life and food-supply, to obtain enough calcium unless the diet
contains at least a pint of milk a day-- milk being a rich source
of it. This is another cogent reason for the greater use of milk
as an article of diet. The diet of pregnant women is often dangerously
low in calcium. Recent researches in America have shown that such
women need 1.6 grammes dally: often they do not receive more than
one-half of this amount. Its deficiency leads to the imperfect
building of bones and teeth, in growing children to rickets and
all its attendant consequences, to malformation or mal-alignment
of the vertebrae and spinal curvature, and to decay of teeth.
To satisfy the urgent demands for this important element elsewhere
it may be withdrawn from the bones--its storehouse in the body.
Not infrequently the normal calcium content of the blood, on which
so many bodily activities rely, is being maintained at the expense
of decalcification elsewhere--of teeth, alveoli and bones. The
clinical expressions of such decalcification are softening of
bone, weakness of bone, increased liability to fractures, retraction
of the alveoli in which the teeth are set, and dental decay. Want
of calcium leads also to nervous excitability and to a condition
known as tetany, to impaired muscular activity, both of voluntary
and of involuntary muscles, and to disturbance of cardiac rhythm
and of the neutrality of the blood; it may also be a cause of
chilblains and of irritability of the skin. Foods rich in calcium
are milk, cheese, turnip-top greens, black treacle, almonds, watercress,
egg-yolk, peas, beans and green leafy vegetables of various kinds.
Phosphorus.--Phosphorus is an essential
component of the nuclei of all cells. It therefore plays a conspicuous
part in all cellular activities. It enters largely into the composition
of the bones and teeth, and is needed for the manufacture of the
lipins which abound in all tissues, and more especially in the
nervous tissues. It should be provided in the diet to the extent
of about 1.5 grammes daily--alike for women and children as for
men--and for the same reasons as for the abundant supply of calcium.
During pregnancy the amount should be increased, according to
recent findings, to as much as two grammes daily.
Deficiency of phosphorus may lead to stunting
of growth, poor bone formation, softening of bone, a certain type
of rickets, tooth decay, disturbance of the normal neutrality
of the blood and to depression of vital processes generally. Foods
rich in phosphorus are cheese, egg-yolk, lean meat, almonds, nuts,
whole wheat, liver, milk, fresh beans, spinach, brussels sprouts
and potatoes.
Iron.--Iron is an essential constituent
of the nuclei of all cells, and as such it is concerned in the
control of all cellular activities. It is an essential constituent
of the red pigment--haemoglobin--of the blood. Haemoglobin is
the carrier of oxygen from the lungs to the tissue-cells; it is
obvious, therefore, that iron in this, if in no other, capacity
plays a vital part in the economy of the body. The daily loss
of iron is from seven to eight milligrammes by way of the faeces
and about one milligramme by way of the kidneys. In all there
are lost about ten milligrammes daily, or about one-three hundredth
part of the total haemoglobin--iron in the body. It has been estimated
that the iron content of the average diet in this country is rarely
more than ten milligrammes, while it is frequently as low as five.
In these circumstances, ill health is likely to arise. This takes
the form of anaemia, which, as is now known, is a common ailment,
especially in infants and in women of the childbearing period
of life; in the former, because of the plaucity of iron in the
mother's or in cow's milk; in the latter, because of its insufficient
ingestion or assimilation.
The diet should contain at least fifteen milligrammes
of iron daily. During pregnancy this amount ought to be increased
to twenty milligrammes. Foods rich in iron are lentils, egg-yolk,
liver, beans, black treacle, oatmeal, whole wheat, turnip tops,
spinach, prunes, dates and raisins. It is to be noted that milk
is poor in iron. Nature compensates to some extent for this defect
in milk by bringing the child into the world with a fair store
of iron in its own tissues; but this store does not always protect
the infant from anaemia when the mother's milk is poor in iron
or when the child is fed on cow's milk.
Iodine.--Iodine is an essential constituent
of the thyroid gland--its chief storehouse in the body--and of
the active principle of the gland, thyroxine. It is necessary
for the normal functional activity of this important organ whose
action is to the oxidation processes of the body not unlike that
of the bellows to the fire--thyroxine speeds up the rate of these
processes. In normal circumstances, the daily requirements of
iodine are about fifty gamma (1/1000th of a milligramme).
Growing children, pregnant and lactating women, need more of it
than others. More also is needed when the diet is rich in fats
or contains an excess of lime, and more in some conditions of
insanitation, of infection as of the intestinal tract and, indeed,
of infections generally. Its deficiency in the diet admits of
the operation of certain agents causing goitre: a malady likely
to give rise to cretinism, deaf-mutism and idiocy in the offspring
of goitrous women. In regions where goitre is endemic, the iodine-content
of water-supplies and locally produced foodstuffs is low. Rich
sources of iodine are sea-foods and cod-liver oil.
Other important mineral elements are magnesium,
copper, chlorine. fluorine and sulphur. The first has important
physiological functions, particularly in relation to the movements
of body-fluids. The second is invariably present in the brain
and has a relation to the blood, being complemental to iron in
the prevention of anaemia. The third (chlorine) plays a leading
part in the alkali chlorides of the blood and tissues and in the
hydrochloric acid of the gastric juice. The fourth (fIuorine)
is a normal constituent of bones and teeth; it is not devoid of
significance in the formation of these tissues. The fifth (sulphur)
in the form of the complex amino-acid, cystine, is essential for
growth, is a constituent of certain catalytic agents, and has
a relation to the nutrition of joints.
It is commonly believed that if the foodstuffs
of which a diet is composed be varied enough, there is little
likelihood of deficiency of any important mineral elements. This
is no doubt true; but the variety is often not sufficiently great
nor of a kind to ensure an adequate supply of them. In this connection
I quote the following from the British Medical Journal
of 29th December 1934: 'The average diet in this country contains
from 5 to 10 mg. of iron.' It is apparent, therefore, that the
average diet is not varied enough to provide a sufficiency of
this most important element, nor is it always varied enough to
provide a sufficient amount of lime. The truth is that the common
belief--safety in variety--is likely to be misleading; for, as
McCollum showed years ago, one can ring the changes on a great
variety of foodstuffs--muscle meats, cereal grains, tubers, roots,
potatoes, peas and beans--and yet have fallure of nutrition unless
the diet contains a sufficiency of the protective foods--milk
and green leafy vegetables. This applies to vitamins as well as
to mineral elements.
The Vitamins
The vitamins, according to present knowledge,
are of five classes, designated by the letters of the alphabet:
A, B, C, D, and E. Each has its own part to play in nutrition--a
part that cannot be taken by any other.
Vitamin A.--Vitamin A is essential to
growth and development of the young and 'to the orderly progression
of nutritional processes at all ages' (Sherman). It is essential
to the young in the way that without a sufficient supply of it
pathological states are likely to arise and to interfere with
growth and development. It is a promoter of vigour and stamina,
and plays a part in maintaining the structure and function of
the nervous system. It is one of the most important of the food
essentials concerned in the efficiency of the function of reproduction
and the rearing of the young; hence the importance of its adequate
supply to pregnant and nursing women. It is a potent factor in
maintaining the resistance of the body to infection. This it effects
by its specific relation to epithelia throughout the body: that
of the skin, of the mucous membranes (particularly of the respiratory
and the alimentary tracts), of the glands of external secretion
and their ducts, of the thyroid, the interior of the eye, the
lungs, the kidneys, the bladder and all passages leading to the
exterior of the body. Its deficiency gives rise to structural
changes in epithelium which impair its functions and lower the
local defences against infection. In this sense, and in this sense
only, it is anti- infective. Diminished resistance to local infection
may be the first evidence of its deficiency, and the pathological
state resulting therefrom the first clinical evidence that nutrition
is at fault. Much more of it is needed for the prevention of infection
than for growth. Let me draw your attention to the kind of change
that is brought about in epithelium by lack of this vitamin. (A
picture showing in cross-section the mucous membrane of the upper
respiratory passage of a rat was here exhibited.) This membrane
is covered by tall epithelial cells, each of which has a fringe
of cilia. A function of these cells is to secrete mucus which
not only traps bacteria but permits the cilia to perform their
movements--this they can only do when the membrane they fringe
is moist and the moisture contains calcium. The function of the
cilia is, by their rapid movements in waves, to propel bacteria
or foreign particles, as of dust, towards the exterior of the
body, whence, in normal circumstances, they are ejected. It has
been estimated that the cilia move at the rate of about 600 times
a minute. Now when the food is deficient in vitamin A the cilia
slough off and the cells themselves lose their secretory character,
becoming horny or keratinized, as it is called. Figure to yourselves
what this means: no longer is this trapping, this propelling of
harmful particles, whether of dust or bacteria or both, possible
in the areas so affected. For, unless the deficiency be very grave,
it is only at certain places that these changes occur. Where they
do occur the local defences are broken down and bacteria are free
to implant themselves in the soil thus made ready for them and
to invade the tissues. And it is a curious fact that, in these
circumstances, bacteria that may otherwise exist as harmless saprophytes
often take on pathogenic properties and become disease-producing.
Mark how serious a view the body takes of these events: at once
it sends up defence forces in the form of round cells to man the
breach, and these may accumulate to such an extent as actually
to form adenoid-like outgrowths.
The maladies resulting from deficiency of vitamin
A are, with the exception of night-blindness, usually the result
of superimposed infection. They involve, singly or in combination,
many systems of the body: ocular, nervous, cutaneous, buccal,
dental, gastro-intestinal, urinary and reproductive. Such diverse
conditions as xerophthalmia, pneumonia, colitis) stomatitis, gastric
ulcer, one form of goitre and stone-in-the-bladder may arise in
consequence of its inadequate supply in the food of rats. Some
of these conditions, such as xerophthalmia night-blindness, stomatitis,
catarrhs of all sorts, and certain skin affections are definitely
known to occur also in man from this cause; and, for my own part,
I do not doubt but that the future will reveal a number of others
that are due also to this cause in man: disease of the respiratory
and gastro-intestinal tracts in particular. It is to be emphasized
that many of the local maladies brought about by deficiency of
this vitamin are often, because of the local infection associated
with it, not readily curable by the provision of the vitamin;
the reason no doubt being that pathogenic organisms, once they
have taken root, are difficult to eradicate, especially in parts
of the body where structural and functional changes have taken
place. The fact that the administration of the vitamin by the
mouth may not cure a certain condition is, therefore, no sufficient
reason for the supposition that its deficiency may not have been
a cause of it. Sub-optimum supply of vitamin A may be associated
with no clinical signs of disease, depending on the degree of
the deficiency, the age of the subject and the absence of infection.
It may, indeed, be only by the sense of well-being, resulting
from its more abundant provision, that its sub-optimum supply
becomes apparent. As Sherman says of it: 'Its bountiful supply
is a bulwark against disease of many kinds, a promoter of vigour,
stamina, and that condition of body and its various parts and
functions which conduces to efficient and prolonged life.'
Rich sources of Vitamin A or of its precursor
(carotene) are animal fats, cod liver oil, milk, butter, liver,
eggs, herrings, carrots and fresh, green vegetables.
Vitamin B.--Vitamin B is a complex, said
to consist of some five or six fractions, each having its own
particular function. Their separation is largely a laboratory
manoeuvre--a feat rarely indulged in by Nature, though some foodstuffs
contain more of one fraction of the complex than of others. It
is enough for the layman to know what are the chief functions
of two of its principal parts: vitamin B1
and vitamin B2 (the latter itself a complex).
Both are essential for growth (Fig. 4); one (B1)
is destroyed by heat; the other (B2) is
not.
Vitamin B1 is intimately
concerned with the maintenance of neuromuscular efficiency throughout
the body, such, for instance, as that of the stomach, the colon
and the heart. Within an hour of the administration of a dose
of the International Standard Preparation of the vitamin to a
person whose diet is low in this factor, but who may show no obvious
sign of its lowness, the heart's action is markedly improved and
remains so for approximately four hours, when the good effect
wears off. If, however, the same dose be given to a person whose
diet contains enough of it, no effect on the heart is observable
on electro-cardiographic examination. In animals (pigeons and
rats), under experimental conditions, its deficiency gives rise
to marked slowing of the heart's action (bradycardia) amounting
sometimes to 'heart-block'. It causes also a slowing down of respiration
and a fall in body temperature and in blood pressure. Its deficiency
has a specific effect on the adrenal glands (causing them to undergo
hypertrophy) and through them, as well as more directly, on the
sympathetic nervous system. Appetite is dependent in great measure,
on an adequate supply of it--appetite for water as well as for
food. It has an important influence on the secretory activity
of the stomach, its deficiency greatly impairing the production
of gastric juices. In its absence or inadequate supply the muscular
movements of the stomach and of the lower bowel are much impaired.
This impairment of the secretory and motor functions of the stomach
deranges the function of nutrition at its very outset. It also
influences nutrition in a number of other ways. Thus it promotes
the assimilation of food and the multiplication of cells (growth).
An interesting example of the latter is afforded by the developing
chick's intestine when grown in vitro. Explanted, about
the eighteenth day of development, in normal fowl plasma, it grows
profusely; but when explanted in plasma from a fowl fed on polished
rice--which is deficient in this vitamin--growth is scanty or
altogether inhibited. Further, if the vigorously growing tissue
be transferred from the normal to the deficient plasma, growth
immediately ceases and the young cells undergo rapid disintegration.
It is notable that intestinal tissue is particularly sensitive
in this respect--a fact which can scarcely be without significance
in relation to the immature gastro-intestinal tract of infants.
Amongst other effects of want of this vitamin
are degeneration of lymphatic tissue, atrophic changes in the
spleen and sex glands, disturbance of carbohydrate metabolism,
reduction of the glycogen normally stored in the liver and the
accumulation of a toxic substance (lactic acid) in certain tissues
which may cause functional paralysis and convulsive seizures.
Beri-beri is always associated with deficiency of this vitamin,
though the vitamin deficiency is not always followed by beriberi;
the deficiency is not the only factor concerned in its causation.
Beri-beri is rarely encountered in this country; but it is not
unlikely that other forms of neuritis, such, for instance, as
alcoholic neuritis, may be due as much to inadequate absorption
of vitamin B1 consequent on derangement
of digestive processes, as to toxic action.
Figure 4. Effect on the growth and mortality of young rats of adding vitamins to a basal diet devoid of them but otherwise complete
The insufficient ingestion of vitamin B1, is a common food fault, due mainly to the
extensive use of vitamin-poor or vitamin-less carbohydrate foods,
such as polished rice, white flour and sugar. It has to be remembered
in this connection that the more carbohydrate eaten the more vitamin
B1 is required. The effects of its inadequate
provision are loss of appetite, impaired digestion, decreased
motility of the stomach, sluggish bowel action, impaired growth
of the young during the lactating period consequent on deficiency
in the mother's milk, deranged function of the adrenal glands
(possibly a cause of distressing dreams), nervousness, loss of
weight and vigour, and fatigue. In infants there may be stiffness
of the arms and legs, rigidity of the neck, restlessness, fretfulness
and pallor. This vitamin has an important relation to the secretion
of milk, much more of it being needed during the lactation period
than at other times. Its abundant provision during pregnancy is
also of great importance. Its richest natural source is dried
brewer's yeast. Rice polishings, bran and wheat-germ are all good
sources of it, as are whole cereal grains. Yolk of egg, liver,
kidney, heart, watercress, cabbage, spinach, lettuce, carrots
and tomatoes are other excellent sources. It is to be noted that
milk and muscle meat are relatively poor in this vitamin, so are
fruits. An important practical point is that, when vegetables
are cooked in water and the water thrown away, more than half
of this water-soluble vitamin is lost.
Vitamin B2 is especially
concerned in maintaining the health of the skin--both that covering
the exterior of the body and that--the mucous membrane of the
alimentary tract--lining its interior. It is concerned also in
maintaining the integrity of the nervous system, and appears to
have some part to play in the prevention of anaemia. It bears
a quantitative relation to the fat-content of the diet: the more
fat ingested the more vitamin B2 is needed--a
fact not to be forgotten when the digestion of fats is found to
be poor.
Deficiency in the diet of this fraction of vitamin
B gives rise to gastrointestinal disorder (degenerative and inflammatory
states, such as gastritis, enteritis and colitis), to lesions
of the skin and, when the deprivation is severe, to mental derangement.
It, or a fraction of it, is specifically related to the disease
known as pellagra; but this relation appears to be much the same
as that of iodine-deficiency to goitre or of B1--deficiency
to beri-beri--it is not the sole, nor probably the ultimate, cause.
Of far greater importance is it to keep in mind that a generous
provision of vitamin B2 is one of the factors
on which the health of the skin, the gastro-intestinal tract and
the nervous system depends. In rats under experimental conditions,
cataract has been observed to result from its want.
It is not yet definitely known whether it is
the B1 or the B2
fraction of the complex which contributes so markedly to the prevention
of microbic invasion of the body. This is not a matter of great
practical importance, so long as it is recognized that vitamin
B does play a part in this connection. Many years ago I showed
that, in animals fed on food deficient in vitamin B, bacteria
were apt to find their way through the walls of the intestine
into the blood-stream. Further, bacteria normally absent from
the small intestine may migrate thereto from the colon where,
normally, they are present; in the latter location they are harmless,
even useful, in the former they have a noxious action.
The vitamin B-complex appears, as does vitamin
C, to have some relation to the nutrition of the joints. Recent
investigations in regard to rheumatism indicate the need for the
adequate supply of both these vitamins in this condition.
Rich sources of vitamin B2
are dried brewer's yeast, liver, kidney, muscle meat, eggs, milk
and green leafy vegetables. It is to be noted that whole cereal
grains are in general poor sources of B2
though relatively rich sources of B1, that
muscle meat and milk, while rich in B2
are relatively poor in B1, and that white
of egg is the only known food in which vitamin B2
occurs without B1.
Vitamin C--Vitamin C is now known to
be identical with ascorbic acid--a potent reducing agent. It is
thought that the biological activity of ascorbic acid may depend
on its double function of oxidation and reduction. If this be
so its deficiency in the diet would involve the depression of
oxidation processes. Vitamin C has a specific relation to the
supporting tissues of the body, 'enabling the cells to produce
and to conserve inter-cellular substances that cause setting of
the matrix in which the cells lie and are supported'--an enlightening
observation which we owe to two American observers. It is as if
the bricks of which a house is built were to produce substances
that caused the mortar supporting them to set, and went on doing
so to prevent its upsetting. This function has a particular concern
for the blood capillaries; the cells comprising which may become
loosened in their settings for want of it and blood extrude between
them into the tissues.
Deficiency of vitamin C may lead to haemorrhages
in various parts of the body, to sallowness and other affections
of the skin, to fragility of bones, swelling of joints, imperfections
in the teeth, unhealthy gums, congestion of the bladder, changes
in the bone-marrow, gastro-intestinal disorder (such as duodenal
ulcer--in guinea-pigs), and to latent or manifest scurvy. Like
vitamin B it has a specific relation to the adrenal glands--its
chief storehouse in the body--which undergo enlargement when it
is deficient in the diet. This observation, which I made in 1919,
calls to mind the enlargement of the thyroid gland--the chief
storehouse of iodine in the body--which results from deficiency
of iodine. Like proteins and vitamins A and B, but in its own
particular way, vitamin C has an anti-infective action. It has,
for instance, recently been shown that guinea-pigs, fed on diets
poor in vitamin C but not sufficiently lacking in it to cause
manifest scurvy, develop the symptoms characteristic of rheumatic
fever when streptococci, isolated from cases of this disease in
human beings, are administered to them; guinea-pigs receiving
diets rich in vitamin C do not, or only in relatively few cases,
develop these symptoms when similarly treated. The same appears
to be true of intestinal tuberculosis: a high proportion of those
receiving too little vitamin C develop tuberculous ulceration
of the intestine when virulent tubercle bacilli are administered
to them by the mouth, while only a small proportion of those receiving
abundance of vitamin C develop this condition when similarly treated.
These observations in guinea-pigs may prove to be of significance
in regard to rheumatism and intestinal tuberculosis in man; for
man resembles the guinea-pig in this that he is equally sensitive
to want of vitamin C.
Rich sources of vitamin C are parsley, orange
peel, green chillies, cabbage, orange juice, lemon juice, brussels
sprouts, caulifower and other green leafy vegetables. It is to
be remembered that leafy vegetables rapidly lose a great part
of their content of this vitamin as their freshness diminishes.
Vitamin D.--The function of this vitamin
is to promote the absorption of calcium from the intestine and
to assist in maintaining its normal level in the blood. It is
a chief regulator of calcium and phosphorus metabolism and the
fixer of calcium in the bones and teeth. Through this regulation
it serves to ensure and to maintain the normal structure of the
bony framework of the body and of the teeth. It is associated,
in the control of calcium metabolism, with the parathyroid glands
whose secretion is a mobilizer of calcium, releasing it as occasion
demands or as exceptional circumstances determine from the bony
structures of the body. The metabolism of calcium is thus controlled
by a substance derived from food as well as by a substance manufactured
by the body itself. The deposition of lime and phosphorus in growing
bones is also related to a ferment--phosphatase--which is normally
present in them.
This vitamin has an important relation to the
bone marrow, helping to ensure the normal proportions of its cellular
constituents. Its deficiency in the diet leads to mar-absorption
of calcium from the intestine, to shortage of calcium in the blood,
to the imperfect deposition of lime and phosphorus in the bones,
and to the occurrence of rickets. The structure of teeth is similarly
impaired by its want, with resultant dental decay. Enlargement
of lymphatic glands in various parts of the body--neck, groin
and axilla--may also result from its inadequate supply. Another
malady to the causation of which deficiency of vitamin D contributes
is osteomalacia; a condition in which great deformity of bones
occurs. This malady is common in certain parts of India and China
and is usually confined to women. A very important consequence
of deformities of bone brought about in these ways is alteration
in contour of the pelvis; it is one that may give rise to serious
difficulties during childbirth. Chilblains may be caused by partial
deficiency of this vitamin in association with calcium-insufficiency.
It is not known whether vitamin D has any special
anti-infective action, though sufferers from rickets are very
prone to certain infections, especially of the respiratory tract.
Rickets of severe type is, happily, much less common in this country
than formerly, although, as recently as 1928, it was stated that
90 per cent of elementary schoolchildren in London suffered from
minor degrees of it.
The animal organism is endowed with the capacity
to manufacture its own vitamin D following exposure of the body
to the ultra-violet rays of the sun. Foods may also be activated
in the same way or by artificial ultra-violet irradiation. Vitamin
D is nowadays manufactured synthetically by the ultra-violet irradiation
of ergosterol. The product is known as calciferol and is potent
in very small dosage.
The sources of this vitamin are relatively scanty:
cod liver oil, halibut and other fish oils, liver, kidney, butter
and yolk of egg are the chief. It is, indeed, difficult in countries
where sunshine is scanty for children to obtain enough of it unless
the diet is fortified by the addition to it of cod liver oil or
of calciferol. In the administration of the latter great care
must be taken to avoid overdosage, the effects of which may be
serious. Rickets is by no means unknown in the tropics, usually
occurring in those castes observing the Purdah system.
Vitamin E.--Vitamin E is concerned in
the maintenance of the functional efficiency of the reproductive
system: a concern which it shares with protein, and with vitamins
A and B. It is not yet clear that it has any very important part
to play in this regard in human beings. It is widely distributed
amongst foodstuffs; occurring in wheat germ, eggs, milk, meat,
lettuce, spinach, watercress, coconut oil, cotton seed and a number
of others.
Vitamins in General
It will be apparent from the foregoing facts
that each vitamin has specific relations to certain structures
of the body: vitamin A to epithelium and nerve; vitamin B to the
gastro-intestinal tract, nervous system and skin; vitamin C to
the cement substance that binds the cells of the body together;
vitamin D to the bones and teeth; and vitamin E to the reproductive
system. Their relations are not, however, confined to these: thus,
one may support another in maintaining the health of the skin,
the teeth, the bones, the gastro-intestinal tract, or the nervous
system; and all are closely intertwined in their action with other
essential constituents of the food. Consider, for example, the
factors concerned in maintaining the structure and health of the
teeth. There are, to begin with, the minerals--calcium and phosphorus--of
which the teeth are mainly composed and of which an adequate supply
must not only be provided in the food but adequately absorbed
from the intestinal tract. There is the vitamin D needed to ensure
both the proper absorption of calcium and its proper deposition--together
with phosphorus--in the teeth. There is the vitamin C required
to maintain the matrix in which the cells of the teeth lie. There
are the vitamins A, C and B2 needed for
the maintenance of the health of the gums and alveoli in which
the teeth are set. All of these are essential to the normal structure
and health of the teeth, and deficiency of any one of them may
give rise to dental decay. The dietetic causes of dental caries
are, therefore, multiple (and not the least of these is the excessive
use of sugar). The same is true of many other diseases of a degenerative
kind in the causation of which malnutrition is concerned. For
the maintenance of health of any organ or part of the body the
adequate supply of all things needed for normal nutrition is necessary.
It is true that the outstanding deficiency of one or other essential
may give to the resultant disturbances of structure or function
characters which we recognize as specific disease entities, but
even then default of other essentials may contribute to their
production.
It is during the early and growing period of
life that an optimum supply of all vitamins, as well as of other
essentials concerned in the maintenance of structure and function
of the body, is so necessary. For the foundations of disease are
often laid by their inadequate provision in early life. This is
particularly true of deficiency of vitamins A and B, which may
leave behind them diseased states as of the gastro-intestinal
tract--that subsequent administration of these vitamins by the
mouth may be unable to remedy, though their parenteral administration
may prove more effective. During pregnancy also--and lactation--an
abundant supply of vitamins of every kind is needful, as well
for the child as for the mother. Indeed, at all times optimum
efficiency of the body and of its various functions depends, in
great part, on an optimum supply of vitamins. Their function is
not merely the prevention of the 'deficiency diseases'--xerophthalmia,
beri-beri, pellagra, scurvy and rickets--with which they are usually
associated by name; being called 'anti-this' or 'anti-that'. The
use of these limiting descriptive terms--'antixerophthalmia',
'anti-beri-beri', 'anti-scorbutic' and so on--however well they
may have served their purpose in the past, when we were largely
groping in the dark, is, as I pointed out fifteen years ago, objectionable.
For they concentrate attention on particular 'deficiency diseases'
and convey the impression that all the vitamins have to do is
to prevent them. Attention is thus diverted from their far more
important relations to structure and functions of the body as
a whole. All these specific deficiency diseases are associated
in their origin with severe degrees of vitamin-deprivation. But
outside the laboratory these severe degrees are encountered relatively
rarely. Milder degrees are much more common; and, as far as vitamins
A, B and C are concerned, bacterial or other pathogenic agents
may, and often do, combine with these milder degrees of vitamin-deficiency
to produce illnesses differing widely from the specific deficiency
diseases with which the vitamins are commonly associated in the
professional and lay mind. The inadequate ingestion of vitamin
A does not, for instance, always cause xerophthalmia; infections
of the lungs, skin or intestinal tract are often the consequences
of it. So, too, with vitamin B: poor appetite, some digestive
disturbance, nervousness, feeble action of the heart, lack of
vigour and fatigue may be evidences of its inadequate supply,
where no signs of beri-beri exist. Similarly, in regard to insufficiency
of vitamin C, there may be no manifest signs of scurvy yet it
may be present in a latent form, as that great authority on the
subject--the late Alfred Hess-- assured us that it often is. No
teaching could be more purblind, in the light of our present knowledge
(incomplete though it be) of the important relations of the vitamins
to structure and functions of the body, than that which affirms
there is no insufficiency of vitamins A, B, C or D because there
is no xerophthalmia, no beri-beri, no pellagra, no scurvy or no
rickets. There may be no vitamin-insufficiency; on the other hand,
there often is. I speak now of optimum health; not of that sub-optimal
state of being which so many are content to regard as good health.
Since the year 1921 I have used every occasion
to emphasize that it is the lesser degrees of vitamin-deficiency,
and the less obvious manifestations of such deficiency that are
of importance in Western countries. A recognition of this fact
is, I believe, essential to the prevention and cure of many of
the commoner sicknesses of mankind--sicknesses to which we cannot
always attach a diagnostic label. 'It is rare', as I wrote in
1921, 'that the food of human beings is totally devoid of any
one vitamin; it is more usual for the deficiency to be partial,
and for more than one vitamin to be partially deficient; it is
more usual still for partial deficiency of vitamins to be associated
with deficiency of suitable protein and inorganic salts and with
an excessive richness of the food in carbohydrates. Consequently,
the manifestations of disease resulting from the faulty food are
compounded of the several degrees of avitaminosis on the one hand,
and of ill-balance of the food on the other. Nor is this all,
for pathogenic organisms present in the body, during the period
of its subjection to the faulty food, contribute their share to
the general morbid results. . . . Other factors also, such as
age, sex, individual idiosyncrasy, rate of metabolism, fatigue,
cold, insanitary surroundings, overcrowding, the varying susceptibilities
of different individuals, of different organs and of the same
organs in different individuals, all play a determining part in
the production of the morbid result of food deficiency. So it
is that in practice the manifestations of deficiency disease are
influenced by a number of factors apart from the actual food fault.
It maybe expected, therefore, that wide variations in the incidence,
the time of onset, and the character of the symptoms will occur
in human beings in whom the dietetic fault has been to all appearances
the same. . . . It is to this variety of morbid change that I
desire to draw attention . . . since it seems to me to impart
to the term "deficiency disease" a wider significance
than has been attached to it hitherto.' At the time these words
were written they were received with some scepticism, yet to-day
'it is becoming generally recognized that much subnormal health
and development, and even incidence of disease, are associated
with a partial deficiency of one or more of the accessory substances'.*
If the knowledge acquired during the past quarter
of a century is to yield its fullest fruit in the betterment of
the national health it must be recognized that an optimum supply
of all vitamins, in an otherwise well- balanced diet, is a prerequisite
of optimum health; and that a minimum supply, while it may suffice
for the prevention of certain specific 'deficiency diseases',
creates the conditions preceedent to the occurrence of a wide
range of other sicknesses.
All of which, in regard to vitamins, is not
to minimize the great importance of other food-essentials in maintaining
nutritional harmony and this, in its turn, the melody of health.
* Medical Research Council's
Report on Vitamins, 1932.
To one whose work has lain in India, and who
for more than twenty years has been engaged in a study of the
relation of faulty food to disease, the belief that such food
is of paramount importance in the causation of disease amounts
to certainty. For there he meets with 'deficiency diseases' of
every kind: xerophthalmia, night-blindness, beri-beri, malnutritional
oedema, scurvy, rickets, osteomalacia, pellagra, angular stomatitis
and certain skin diseases that are of this order. There, too,
he encounters many maladies, not usually regarded as of malnutritional
origin, which experience, both in the laboratory and the field,
teaches him to regard as wholly or in part of this nature: gastro-intestinal
diseases of various kinds, including nonspecific colitis and peptic
ulcer, certain respiratory diseases often found in association
with xerophthalmia, urinary calculus, some ulcers and cardiac
disorders, pyorrhea and a number of others. Further, he soon becomes
aware--if he had not avallable for his enlightenment the testimony
of many shrewd observers who have gone before him--that malnutrition
is a chief cause of the lowered resistance to infection exhibited
by so many of the Indian people; the chief reason why they succumb
by hundreds of thousands to the ravages of such scourges as malaria,
kala-azar, cholera, dysentery, leprosy and tuberculosis. For him
the soil assumes an importance even greater than the seed, and
he becomes impressed by the urgent necessity to render it inhospitable
to the growth of the seeds of disease by adequate nourishment
of the body.
If we look upon 'infection' of whatever kind,
be it due to microbe, protozoa, metazoa, or invisible virus, or
to the intervention of vectors of pathogenic agents, as the evidence
of personal or environmental uncleanliness, then it may be said
that the two chief causes of disease are faulty food and dirt.
These two are the senior partners in the criminal business of
disease-production--each the coadjutor of the other. It is along
lines of improved cleanliness, both personal and environ mental,
that the triumphs of modern medicine have lain; it is along lines
of improved nutrition that greater triumphs still remain to be
achieved. Some years ago I made the statement that 'the newer
knowledge of nutrition is the greatest advance in medical science
since the days of Lister. When physicians, medical officers of
health and the lay public learn to apply the principles which
this newer knowledge has to impart . . . then will it do for medicine
what asepsis has done for surgery.' I see no reason, in these
later days, to detract from this view; on the contrary, there
is every reason to emphasize it the more, particularly in regard
to preventive medicine.
In this country the conviction that faulty food,
and the faulty nutrition resulting from it, is a principal cause
of ill health, does not appear to be acquired so readily as it
is in the tropics. Perhaps it is that as an island race we have
no others, at close range, with whom to compare ourselves. The
tribes of the Indian Frontier are far removed from the slums of
our great cities; and it would be as difficult for the slum dweller
to realize the perfection of physique to which these tribes attain,
though nourished on the simplest and least varied kinds of foods,
as it would be for the Frontier tribesman to understand that the
physical imperfections of so many of the dwellers in the slums
are largely due to the imperfections of the foods on which they
are reared. Nevertheless, things nutritional are not, in essence,
so different in India and in England as they may seem.
Figure 5. Insured persons in representative areas, urban and rural, in England and Wales--proportion per 1,000 cases of certain diseases to total cases treated by Insurance Practitioners, 1933. (Prepared from the Annual Report of the Chief Medical Officer of the Ministry of Health for the year 1933)
Diet and Incidence of Disease
Let me remind you of the experimental contrast
to which I drew your attention in my first lecture (Fig. 3). You
may remember that the great majority of the rats in that experiment
enjoyed good health when fed on a well-constituted diet such as
is used by Sikhs of the better class, while the great majority
of those fed on an ill-constituted diet, such as is commonly used
by the poorer classes in this country, developed two chief kinds
of disease: respiratory and gastro-intestinal. You may remember
also that the majority of rats fed on a diet in common use by
the people of Madras also suffered from disease of these two systems
of the body. The diet of the poorer class Britisher was, in fact,
little or no better, so far as disease prevention was concerned,
than that of the Madrassi. Here, now, is a diagram prepared from
the material provided in the Annual Report of the Chief Medical
Officer of the Ministry of Health for the year 1933 (Fig. 5).
You will observe that amongst every 1,000 sick persons of the
insured classes in England and Wales no less than 250 suffered
from diseases of the respiratory system, and no less than 110
from diseases of the digestive system. Diseases of these two systems
of the body accounted for more than one-third of all illness in
these classes of the community. A similar diagram, prepared from
the Report (1933) of the Surgeon-General with the Government of
Madras, reveals that amongst sick persons of the hospital class
in Madras, no less than 183 out of every 1,000 suffered from diseases
of the digestive system and 76 from diseases of the respiratory
system; or more than one- quarter of the total sick. If from the
calculation we remove the sufferers from purely tropical ailments,
then in Madras also disease of these two systems of the body would
account for approximately one-third of all sickness. I submit
that if these diseases be, as they are, a chief consequence of
feeding rats--living in an equable climate and as far as possible
protected against infection or influences favouring it--on a diet
in common use by the poorer class Britisher and, also, a chief
consequence of feeding them on a diet in common use by the poorer
class Madrassi, then these diets per se are likely to be
favourable to the production of such maladies in human beings.
I say these diets per se, for I am well aware that other
influences--climatic conditions, cold, and factors favourable
to the spread of infection--play their part in the production
of these illnesses, especially those of the respiratory system.
Indeed, it is apparent, from the difference in incidence of respiratory
disease amongst insured persons in this country and amongst Madrassis,
that this must be so; for this incidence was more than three times
greater in the former that in the latter, due, no doubt, to the
differing climatic conditions. But, in general, the mal-effects
of the poorer class Britisher's diet, as exhibited by rats, are
similar in kind to those of the Madrassi diet.
It will be of interest now to consider the difference
in incidence of certain diseases in Madras and the Punjab--having
in mind that the diet of the poorer classes in this country affords
as little protection against disease as that of the Madrassi,
and that the diet of the people of the Punjab is, in general,
of better constitution than either--though that of the poorer
class Punjabi may lack a sufficiency of vitamins A and C. In the
first place, we find that tuberculosis is nearly twice as common
in Madras, and one is reminded, in this connection, of how closely
the incidence of this disease is related to malnourishment in
England. Next, we find that leprosy, a malady from which this
country is happily free--but one allied in some ways to tuberculosis--is
much more common in Madras than in the Punjab (Fig. 6). We find,
too, that other diseases of a chronic and degenerative kind are
more common in the south than in the north of India: peptic ulcer
(gastric and duodenal) is fifty-eight times more common, rheumatism
is nearly five times as common, cancer is 3 5 times as common,
anaemia and malnutritional diseases generally (excluding beri-beri,
which rarely occurs in the Punjab) are more than twice as common;
rickets is four times as common. Diabetes and mental disease are
three times as common, disorders of the heart four times, nephritis
ten times, and infestation by round worms twenty times as common
in Madras, while ulcers, skin diseases and various other local
ailments are all more common in Madras. These differences in the
incidence of disease can, I think, be accounted for in large part
by the difference in the nutritive quality of the diets of the
two peoples, and in view of the poor quality of the diet of many
of our own people. they are, to say the least of it, suggestive.
They suggest that a similar relation of food of poor quality to
the incidence of human ailments may be expected in other countries
and in other peoples. That such a relation actually does exist
elsewhere is exemplified by the studies made by Drs. Orr and Gilks
of two African tribes whose diseases could be correlated with
the defects of their diets and the incidence of these diseases
with differences in these defects. Indeed, the experiences of
a number of skilled observers in Africa provide abundant evidence
that, there also, improper quality of human food is a factor of
fundamental importance in the causation of disease.
Figure 6. Nutritive values of diets in common use in the five main divisions of India (as determined by feeding experiments on rats) compared with the incidence of certain diseases per 1,000 of sick persons in these divisions.
Partial Degrees of Vitamin Insufficiency
In a book--Studies in Deficiency Disease--which
I published as long ago as 1921, I provided experimental evidence
which appeared to me to warrant the conclusion that food of improper
constitution is responsible for a large proportion of ill health
in this country. I emphasized then, and I have continued to do
so on every convenient occasion since, that the less obvious manifestations
of 'deficiency disease' were of vastly greater practical importance
than the more obvious but less common diseases, such as scurvy,
beri-beri, rickets, etc., to which the term 'deficiency disease'
was usually restricted. I pointed out that the milder grades of
deficiency of certain food-essentials--particularly of vitamins
and mineral elements--were much more widespread among the people
than the severer grades; and that they led as surely, though more
slowly, to a lowering of vital processes, to impaired resistance
to microbic and other pathogenic agents of disease and to the
development of maladies of many kinds. At that time (1921) I laid
emphasis, as I still do, on the consequences of the inadequate
ingestion of vitamin B1, which appeared
to me to be a conspicuous fault of the diet of the British people,
a fault due to the extensive use of vitamin-poor white flour and
to the inordinate use of vitamin-less sugar. Excessive richness
of the average Britisher's diet in these two carbohydrates gives
rise to insufficiency of vitamin B1 for
two reasons: the first, that the food as a whole does not contain
enough of it, and the second, that relative to the richness of
the diet in carbohydrates this vitamin is rendered still more
deficient; for we now know that the greater the consumption of
carbohydrates the more vitamin B1 is needed.
Consider, in this connection, the chart which I now show you (Fig.
7). It is self-explanatory and I need not, therefore, amplify
its description. It illustrates, however, two things to which
I would draw your attention: first, the inadequacy of white flour
as compared with freshly-ground whole wheat flour; and second,
the striking difference in appearance of rats fed properly from
infancy as compared with those who in earlier life have been improperly
fed and have to make up for lost time when properly fed at a later
age.
In this connection, also, let me draw your attention
to the results of a large-scale experiment, carried out by Professor
J. C. Drummond and his colleagues, to which he made reference
in his Harben Lectures for 1933. This experiment was designed
with the object of learning whether or not mild degrees of vitamin
B1 deficiency gave rise to disease, when
animals (rats) were fed for long periods on food having this fault
but otherwise satisfactory. Speaking of the results of this experiment,
and of the kinds of disease from which the animals suffered, he
said: 'He (McCarrison) is unquestionably right in insisting that
vitamin-deficiency--and it must be remembered that he stresses
at every turn the importance of recognizing the widespread occurrence
of mild deficiency--is directly or indirectly responsible for
a very large proportion of ill health to-day.' And in his Lane
Medical Lectures, a year later, he repeats with even greater emphasis
the same assertion. It is not only amongst the poorer classes
in this country, but also amongst those who are better off, that
the diet is commonly excessively rich in vitamin-poor, mineral-poor
starchy foods and in protein-less, vitamin-less, mineral-less
sugar. It is impossible for people subsisting on such diets to
remain in good health. 'It is only being gradually realized,'
says Dr. Friend, whose recently published book, The Schoolboy,
is so valuable a contribution to the problems of food and nutrition,
'that the deficiency of white bread in vitamin B1
is one of the most serious dietary deficiencies to which our populations
are being subjected at the present time.' To this I would add
that the inordinate use of refined sugar is one of the most serious
addictions of the day. That the insufficient ingestion of Vitamin
B1 is an important and widespread cause
of ill health--especially of gastro-intestinal ill health--is
now recognized in America, where 'the bread-meat-potato-sugar'
diet of many American people has recently been shown to be dangerously
low in this important factor, unless it is supplemented with a
sufficiency of milk, eggs, fruits, nuts and vegetables (Sure,
1933). And if in America, why not in this country also, where
the average diet is of the same 'bread-meat-potato- sugar' sort?
According to American observers the mal-effects of such a diet
are chiefly to be observed in children who exhibit poor appetites,
poor growth, nervousness, constipation and other digestive disorders:
effects which I observed, and recorded, in monkeys eighteen years
ago. For many years past I have advised European mothers in India
to supple" ment the feeds of their infants with a watery
extract of yeast in order to ensure an abundant supply of vitamin
B', which cows' milk certainly does not provide in that country.
A similar recommendation is now widely made in America, following
the finding that not only cow's milk but the pooled breast milk
of nursing women is relatively poor in vitamin B1--poor
because the women's own diets are poor in it. Many experiments
have been made within the last few years on American children,
the results of which show the good effect of the supplementary
provision of vitamin B1: better growth,
better appetite, better assimilation of food and greater freedom
from digestive disorders. Some clinicians in that country have
come to the conclusion that a large proportion of the infantile
mortality during the first year of life which is associated with
gastro-intestinal disturbances may be due to vitamin B1
deficiency consequent on the relative poverty of mother's milk
and of cow's milk in this vitamin; a conclusion that has also
been reached recently by certain observers in the Near East.
National Ill Health
What evidence is there of physical inefficiency
in this country? and what that such as may exist is related in
its origin to faulty nutrition? For answer to the first of these
questions I must turn to certain authoritative publications. From
the first of these--the Report of the Adjutant-General for the
year 1934--I quote the following passage: 'What was disconcerting
to any citizen with a care for the good of his country was that
over 52 per cent of the men who went to the recruiting office
did not come up to the physical standard laid down. In the big
industrial areas of the north the percentage of rejections rose
to sixty-eight.' The opinion of a high military medical authority
was that the chief cause of the men's rejection was malnutrition
during childhood. These figures are in themselves sufficiently
disconcerting, but more so perhaps when it seems likely that the
men who did present themselves for recruitment were not so physically
impaired as many who did not. And if so high a percentage of men
falled to come up to the by no means exacting physical standard
laid down by the Army authorities, how many of their womenkind
were likely to be physically inefficient?
Another example, also of recent date, is still
more disturbing: Not long ago the Pioneer Health Centre in Peckham
carried out a survey of families of the artisan class, for whom
the centre is intended. This survey revealed that 90 per cent
of those over twenty-five years of age had some physical defect.
From another source I glean the following statement: 'Among the
insured population there were lost in 1933 a total of 29,000,000
weeks of work. To this staggering loss must be added the cost
of replacement of labour and the expense entalled in the care
of the sick during the period of incapacity. These figures represent
a heavy burden upon the community which is largely unnecessary.'
It is a burden however, that the community must continue to bear
until it has learned that to be physically efficient the individuals
comprising it must not only be taught to practice the principles
of nutrition, but be provided with the means to practice them.
It is to be noted in connection with this enormous amount of certified
sickness that it was not of the killing kind--'the people were
sick but not mortally sick.'* (*Spectator,
Oct. 19, 1934, p. 586. )
There is, too, the very high incidence of anaemia,
due to deficiency of iron, in working-class women, to which attention
has recently been drawn by Professor Davidson of Aberdeen. 'If',
he says, 'the percentage of anaemic women found in Aberdeen is
present in the industrial areas of the South (and we believe that
anaemia may be even more serious there, since economic conditions
are worse and the cost of living higher) then the loss of economic
efficiency of the working-class mothers in this country must be
enormous.'
The still very high incidence of tuberculosis,
especially in adolescence, is another outstanding evidence of
national ill health: 'During the last completed decade, 1921-30,
there were, roughly speaking, forty-five thousand deaths of males
and an equal number of females at ages 15-30. Amongst the males
very nearly one-third of this mortality was due to tuberculosis
while amongst the females the proportion was as high as one-half.'**
It seems probable that a principal, if not a paramount, cause
of this high incidence of, and mortality from, tuberculosis at
this particular period of life is faulty food deficient in vitamin
A, involving a low content of this vitamin in lung tissue and
consequent susceptibility of the lung to infection. (**Report
of the Chief Medical Officer of Health, 1933.)
As a final example of the prevalence of physical
inefficiency, malnutrition in childhood may be cited. 'In his
Annual Report for the year 1934, the Chief Medical Officer of
the Board of Education repeats the emphasis of former reports
on the necessity for satisfactory nutrition. During the routine
medical examination 12 children per 1,000 were found to be malnourished
and 14 per 1,000 undernourished' (I quote from the British Medical
Journal). It may be taken as certain that a major proportion of
this faulty nutrition was due to food of improper quality or to
insufficient food or to both. Believing, as I do, that sickness
is more often the result of malnutrition than malnutrition the
result of sickness, I venture to think that the evidences of malnutrition
in schoolchildren are likely to be more widespread than these
figures indicate. For it is not only that children suffering from
malnutrition are underweight or under-grown; that there is a disproportion
between their weight and height; that their posture is poor; that
they are often round- shouldered and have protruding bellies,
winged scapulae and lordosis; that they are of poor muscular development
and easily fatigued; that they are irritable, haggard, anxious
and, perhaps, mentally slow if not precocious; that they are wakeful,
restless, and often troubled with unpleasant dreams; that they
have headache and fleeting pains, sometimes in one part of the
body, sometimes in another; although all these are signs of malnutrition.
But there are others, indicating disturbances in structure or
in function of organs or parts of the body: the circulation is
poor; the skin is mottled or dry and hot, or moist, cold and clammy;
there is usually anaemia; the digestive system is quite commonly
unstable or disordered, constipation is frequent or may alternate
with diarrhoea, the appetite is capricious--the desire for 'sweets'
is often inordinate-- dental caries is the rule--and susceptibility
to infection is very marked, especially infection of the upper
respiratory passages. It is well enough to say that malnutrition
may be brought about by faulty health habits or by physical defects,
such as dental decay or gastro-intestinal disorder; it may. But
these physical defects, this bad or capricious appetite, this
constipation or digestive disturbance, this anaemia, this poor
circulation, this faulty function of the skin--these are themselves
consequences of faulty nutrition and, as a rule, it is this that
gives rise to them, not they that give rise to the faulty nutrition.
If we take this view of 'mal-nutrition' in schoolchildren--and
for my own part I believe it to be the correct one--then it will
be found that there are in this country not 12 per 1,000 who are
suffering from it, but several times that number; nor will it
be found to be confined exclusively to the poorer classes. Indeed,
the widespread incidence of dental caries and of minor rickets
is, in itself, sufficient evidence that this is so. There is one
certain means of detecting dietetic malnutrition and that is by
the assessment of the nutritive value of the diet that is actually
being consumed; and in making this assessment attention must be
paid as much to such essentials as calcium, phosphorus, iron and
iodine as to vitamins, proteins and energy-bearing foods. If the
diet does not contain in adequate amounts all elements and complexes
needed for normal nutrition, then the user of it is suffering
from, or will suffer from, malnutrition. It seems probable that
a cause of malnutrition which may be overlooked is the non-provision
of sufficient energy-bearing foods to meet the enormous expenditure
of energy by growing children consequent of their bodily activities
in sports and games.
The Death-rate and National Health
It is commonly stated that because the death-rate
in this country is falling the national health is improving. Recently
a writer in The Listener (20th November, 1935) voiced his
dissent with this statement so pertinently that I am prompted
to quote the major part of his letter, though recognizing that
the falling death-rate is an achievement of which the public health
services have every reason to be proud. This writer says, 'Again
and again this fallacy appears in the Press. Why is it assumed
that a falling death-rate connotes a higher standard of health?
To save a man's life by drugs or surgery does not necessarily
make a healthy man of him. The national health is the sum total
of the healths of individuals; it can be nothing else. If the
reasoning "low death-rate, therefore good health" is
sound, then if in an institution filled with incurables there
is no death during the year, the death-rate becomes nil, and consequently
the institution the healthiest place in England, though there
is not a single healthy person in it.' The same writer goes on
to say: 'What we should like to know is the number of semi-invalids
carried by the nation; why all hospitals and nursing homes, etc.,
are full. . . . Why, under National Health Insurance, the increase
between 1920 and 1930 of short-term (not exceeding six months)
sickness was 109 per cent, of long-term (exceeding six months)
230 per cent; why the enormous decline in quality of eyes and
teeth.' I am convinced that faulty nutrition due to the long-continued
use of food of improper quality provides a no inconsiderable part
of the answer to these questions.
Effects of Improved Diet
What evidence is there that by the provision
of properly-constituted food, and of the hygienic amenities that
should go with it, the physical condition of the people can be
improved and disease prevented? There is, to begin with, the evidence
provided by Dr. Cory Mann, at the instance of the Ministry of
Health and the Medical Research Council, which demonstrated the
unique value of milk as a food and the great improvement brought
about in the physical condition of children by its adequate provision.
Similar results have within recent years been obtained by investigators
in Scotland. There is abundant evidence of the value of the free
meals now issued, in increasing numbers, to poorer class schoolchildren,
and of the value of the cheap milk made available by the Ministry
of Agriculture. In a private communication which Miss Joan Fry
made to me some time ago she spoke of the improvement in the health
of the children of the unemployed allotment holders, under the
beneficent scheme of the Society of Friends, consequent on their
greater use of fresh vegetable foods. But perhaps the most valuable,
because the most extensive and complete amongst investigations
of the kind, is that recorded by Dr. G. E. Friend, Medical Officer
of Christ's Hospital, Horsham. In his book, to which I have previously
referred, he recounts the dietetic history of the school and the
results of his physical and clinical surveys. These show that
during the period for which reliable data have been collected
there is a continuous upward trend both of weight and height of
the boys consequent on improvements effected in the school dietary.
Further, there is a definite decline in certain classes of illness,
particularly of septic conditions, a diminution in the amount
of dental caries, and a remarkable drop in the incidence of fractures
and bone injuries. It cannot be doubted but that these results
are in great part due to dietetic improvements, though improvement
in hygienic conditions generally no doubt contributed its share
to them. Nor have I any doubt in my own mind that had the dietetic
improvements approached nearer to the provision of a perfectly-constituted
diet, their beneficial effects would, with respect to the health
of the boys, have been still more striking.
Chief Faults of British Diets
If now we turn to the Report of the Chief Medical
Officer of Health for the year 1933, we find therein a certain
uneasiness that all is not so well with the nutrition of the British
people as it might be. It is affirmed that the evidences of malnutrition
are not widespread. This is no doubt true of its grosser evidences.
But is it true of the less obvious manifestations of faulty nutrition?
If, as I maintain, the latter include many forms of subnormal
health, not all of which are scheduled in the Nomenclature of
Disease, and of chronic ill health--many, in short, of the commoner
degenerative ailments from which the people suffer: digestive,
respiratory, osseous, arthritic, cardiac, haemic, glandular, inflammatory,
etc.-- then are the evidences of malnutrition, indeed, widespread.
We may read in this Report that the food-essentials
most likely to be deficient in the diets of the people of this
country are proteins of high biological value, calcium, iron and
vitamins A and D; and we may. perhaps, conclude from the use of
the words 'most likely' that the diets of our people are not uncommonly
deficient in one or more or al} of these essentials. If you are
inclined to accept my own opinion, after what I have told you,
there may be added to these likely deficiencies that of Vitamin
B1. I was assured recently by one who labours
in the East End of London that such 'fresh' vegetable foods as
utimately penetrate into that locality are usually many days old;
and I am reminded, in this connection, of certain interesting
observations made some time ago by one of my Indian assistants.
He found that within seventy-two hours of gathering green vegetables
from my well-tended kitchen garden in Coonoor, they lost the major
part of their vitamin C content. I do not know whether the rapidity
of this loss would be as great in England, where climatic conditions
are so different; but it seems safe to assume that by the time
their sparse supply of leafy vegetables reaches the dwellers in
the East End of London the vitamin C content is considerably reduced.
From which assumption I would be inclined to expect an inadequate
intake of vitamin C by relatively large numbers of people in the
slums of our great cities. But it is no longer necessary to make
such assumptions, for in the 'Report on the Physiological Bases
of Nutrition', recently submitted by a committee of experts to
the Assembly of the League of Nations, it is stated that 'deficiencies
in important nutrients are a common feature in modern diets, and
these deficiencies usually occur in the protective foods (foods
rich in minerals and vitamins) rather than in the energy-giving
foods.' [The comment may, however, be made that the deficiencies
do not occur in the protective foods themselves, but in modern
diets because of the scanty use of the protective foods.]
We have, too, the authority of the Committee
on Nutrition set up by the British Medical Association (1933)
that 'a shortage of calcium, phosphorus and iron is not uncommon'
in the diets of the people of this country. Let us, for a moment,
refer back to my second lecture and see again what this not uncommon
shortage means. It means, or may mean according to the degree
of shortage, impairment of every vital function, stunting of growth,
poor physique, poor bone formation, softening of bone, rickets
(not necessarily of the florid type), tooth decay, crooked spines,
impairment of muscular efficiency, including that of the gastrointestinal
tract and heart, abnormal response of the nerves to stimuli, tetany,
disturbance of menstruation and lactation, disturbance of the
neutrality of the body and of the interchange of body fluids,
ana emia and all its attendant consequences. This is what a shortage
of calcium, phosphorus and iron means. And if with these we are
to include a shortage of vitamins A and D, as the Report of the
Chief Medical Officer of Health suggests we may, and of vitamins
B and C--as there is good reason to believe we should--then to
these consequences of mineral shortage there are to be added those
of vitamin shortage, in themselves a formidable array and not
the least important of which is lowered resistance to local infections.
To those who do not know what the shortage of these essentials
means, the mere statement that it commonly exists is not impressive.
But to those who do--and you are now amongst that number, if you
were not so before--it must be obvious that faulty food is directly
or indirectly responsible for a very large proportion of ill health
to-day. If it be not, what then is its cause? You may search in
vain for a more satisfying explanation of it.
Prevention of Disease by Diet
Concerning the matter of disease prevention
and of the part which properly constituted food may play therein,
I need give only three examples: the first provided by Miss Margaret
McMillian in her book The Nursery School--which should
be an obligatory text-book for every student of medicine; the
second by the Papworth Village Settlement for sufferers from tuberculosis;
and the third by the ante-natal work now being done in Dublin.
Many others could, of course, be given. Hear what Miss McMillan
had to say of the weakly and ill-conditioned children who came
from the slums of Deptford to her nursery school; children, rickety
and bronchitic; children with adenoids and dental caries; children
with inflammatory states of eyes nose, ear and throat. After they
have been nurtured and properly fed for three or four years they
are, she tells us, almost all cured of any ailments they may have
had, 'they are all straight and well grown, the average child
is a well-made child, with clean skin, alert, sociable, eager
for life and new experiences'. He does not need, she says, to
seethe doctor or the dentist, and he has none of the minor ailments
that affect the children of the slums. Surely this is an achievement
of the highest order, an answer to the question how best to deal
with 'the minor ailments that affect the children of the slums',
and a cogent reason for the establishment throughout the length
and breadth of the land of nursery schools of the McMillan type.
It is a heartening sign of the times that the present Government
intends actively to encourage their establishment.
And at the Papworth Village Settlement for the
subjects of tuberculosis, what do we find? That in this village
of 400 persons no child born there during the twenty years of
its existence has, while a member of the community, contracted
tuberculosis of the lungs, bones, joints, cerebral membranes,
nor indeed any clinical form of the disease. Yet these children
are the offspring of parents who suffer from tuberculosis and
are in constant contact with them. How has this remarkable achievement
been brought about? Sir Pendrill Varrier-Jones, to whose endeavours
it is due, explains it as follows:
'1. Adequate food supply. Ignorance as to dietetic
values is dispelled by advice at the clinic, by lectures and by
the village nurse. Also by actual demonstration by food supplied
from the Central Institution at small cost.
'2. Adequate food supply is possible because
there is an adequate and prolonged parental income, maintained
by means of assured employment.
'3. Freedom from anxiety as to loss of employment;
therefore expenditure can be budgeted in advance.
'4. No risk of unemployment after breakdown;
the income being maintained meanwhile (a) in the case of
pensioners, by a pension, and (b) in the case of non-pensioners,
by the Friendly Societies' contributions supplemented by the Welfare
Fund.
'5. Proper housing, which allows medical advice
to be put into immediate practice; such as through and thorough
ventilation in living rooms; isolation of infected persons in
bedrooms or verandas. That is to say, avoidance of mass dose.
'6. Public opinion, which makes it possible
to live with windows open without being jeered at; to use sputum
pots in the house, and pocket flasks out of doors, without being
shunned or made conspicuous.
'To sum up--economic conditions determine the
spread or otherwise of disease. To prevent disease it is necessary
to create an environment rather than to give a dole where there
is no opportunity for money to modify the condition of its recipient.
The child's resistance to disease is maintained by (a)
adequate nutrition, and (b) the absence of mass dose of
infection.'
The ante-natal work which I was privileged to
see when in Dublin a few years ago is another activity that is
yielding remarkable results, because it is based on the sound
foundation of improving the nutrition of expectant and nursing
mothers. Three months before the expected birth of their babies
the poorer class women come daily to certain centres, where they
receive an excellent midday meal. They are cared for during their
confinement and a fortnight thereafter they continue their visits
to these dinner-centres for another three months. I am told that
the infantile mortality amongst the children of these women is
approximately one- third of that in women of the same class who
cannot or do not avall themselves of these facilities or for whom
there are, for lack of funds, not sufficient centres.
Maternal Mortality
There is much talk at the present time of the
high rate of maternal mortality in this country, and much argument
in regard to factors that may or may not be concerned in its causation.
Amongst these faulty nutrition has come in for its share of blame.
How far it is to blame we do not yet know, since the matter has
never been thoroughly investigated. But it is a false argument
which would maintain that because in some places maternal mortality
is higher in well-to-do women than in women of the poorer classes,
faulty nutrition can have nothing to do with it. For some women
amongst the better classes have no idea how to feed themselves
properly during or after pregnancy. There is abundant evidence,
derived from experiments on animals, that the activity proper
to the function of reproduction and to the health of the reproductive
tract is influenced unfavourably by faulty nutrition. Of particular
importance in this connection is insufficiency of vitamin A. It
has recently been found (Mason) that levels of vitamin A-deficiency
which are insufficient to produce xerophthalmia result in marked
disturbances of the reproductive function in female rats. These
include difficult labour, often associated with uterine bleeding
and infection. Observations such as these may have an important
bearing on maternal mortality in human beings; for of this we
may be certain, that unless the diet of the expectant mother conforms
in every detall to the physiological requirements of pregnancy
her chance of surviving the ordeal of childbirth will be lessened.
In my second lecture I mentioned, under the various food-essentials
there discussed, the amounts of some of them that are needed during
pregnancy. These may be enumerated again: a well-balanced diet
containing 70 grammes of protein, of which one-third must be derived
from animal sources; an abundance of all vitamins, including vitamin
D, which, however, should be provided in the form of cod liver
oil so as to avoid the risk of overdosage and as an additional
source of iodine; 2 grammes of calcium; 1.6 grammes of phosphorus;
0.3 gramme of magnesium; and 20 milligrammes of iron. Personally,
I believe that the best diet for expectant mothers is one made
up of whole cereal grains, milk, milk products and eggs, with
fresh green vegetable foods and fruit in abundance.
Mention has already been made of the part which
antecedent rickets and osteomalacia may play in increasing the
risks of childbirth by causing alterations in shape of the female
pelvis.
'Building of an A1 Nation'
If I have convinced you of the fundamental importance
of food in relation to public health, it will have become obvious
that one of the most urgent problems of our time is how to ensure
that each member of the community shall receive a diet that will
satisfy his or her physiological needs. It is clear that to achieve
this much-to-be-desired end many barriers--poverty, unemployment,
apathy, ignorance, prejudice, habit--must be surmounted, and many
interests--agricultural, industrial and economic--readjusted.
To do so is, in the main, a primary function of Government. For,
as Carlyle expresses it: 'Wherever the health of the citizens
is concerned . . . all governments that are not chimerical make
haste to interfere.' During the recent election campaign one read
of plans for 'the building of an A1 nation'; ante-natal, child-welfare
and maternity services were to be improved and extended; nursery
schools for children under school age were to be actively encouraged;
increased facilities for treatment, particularly dental treatment,
were to be provided, orthopaedic centres and open-air schools
were to be formed; the medical insurance scheme was to be extended
to include persons of younger age; physical education was to be
undertaken. All these are well enough--and laudable; they are,
indeed, essential parts of a properly organized policy of health.
But without measures that will ensure the better feeding of the
people they cannot, like a diet inadequate in vitamins though
complete in other regards, achieve the end in view-- 'the building
of an Al nation'. But while the main burden of achieving this
end must rest on Government--and a heavy burden it is--there is
much that individuals can do for themselves, much that the medical
profession and the professions allied to it can do, much that
the teaching profession can do, much that all people of education
can do. For they can make it their business thoroughly to acquaint
themselves with the principles of nutrition, to practice these
principles and to inculcate them in others. These principles are
not difficult of comprehension, their practice is simple, and
the benefits to be derived from their practice are sure. Fifteen
years ago, in a book from which I have ventured to quote already,
I wrote as follows: 'With increasing knowledge of nutritional
problems, it has become apparent that our dietetic habits need
remodelling, and that education of the people as to what to eat
and why they eat it is urgently necessary. It is clear that green
vegetables, milk and eggs should form a far higher proportion
of the food of the nation than is now customary. So far from curtalling
the beneficent scheme whereby portions of land were made avallable
during the war for cultivation by allotment holders, this scheme
should be extended and facilities given to allotment holders for
the keeping of fowls. Municipalities and other public bodies should
concentrate on the provision of an abundance of milk, eggs and
vegetables, for there is no measure that could be devised for
improving the health and well-being of the people at the present
time that surpasses this either in excellence or in urgency.'
To-day, fifteen years later, there is little I can add to this
exhortation. Its truth is now generally admitted. It is, indeed,
the essence of the 'Report on the Physiological Bases of Nutrition'
submitted by a special committee two months ago to the Assembly
of the League of Nations. It emphasizes two needs, as urgent to-day
as when these words were written: the need for education in the
principles of nutrition and the need for the employment of many
of our 'unemployed' in the production of more milk, more eggs
and more vegetable foods. Concerning this matter of the employment
of the unemployed, I need only point to the splendid efforts of
the Society of Friends; efforts which provided assistance for
120,000 unemployed men in 1934, and enabled them to produce fresh
foods to the value of £600,000. I understand that the sole
barrier to its further extension is want of funds. In a letter
to The Times, about ten months ago, I appealed, in this connection,
for the more prudent expenditure of public funds. I repeat the
appeal here: 'Year by year we import vast quantities of vegetables
all or most of which could be produced in our own country and
by our own people. Long before these vegetables reach consumers
of the poorer classes they have lost, especially those of the
green leafy kinds, much of their health-promoting properties.
. . . Surely it is prudent to provide our people with these important
foodstuffs in a state as fresh as possible. Their production should
therefore be greatly extended and their speedy distribution ensured.
'It is schemes such as that of the Society of
Friends for the provision of allotments for the unemployed and
for settlement on the land that deserve generous financial support
rather than the expenditure of vast sums on the production of
a food-material (sugar) whose consumption by the nation as a whole
is vastly in excess of the nation's need for it. The need of our
people for fresh vegetable foods, procurable at a cheap rate,
is great--as great as their need for clean, cheap milk. Thousands
of our people stand idle in the market place who would be well
employed in the production and distribution of these health-giving
foods. It should not be beyond the organizing capacity of a nation
that produced a vast citizen army to meet the curse of war to
organize a citizen army to meet, by the adequate production and
distribution of fresh vegetable foods, dairy produce and eggs,
the curse of preventable disease'. To this last phrase I can add
nothing except to say that it envisages what England needs, and
needs most urgently; for in this way there lies a solution of
some of the problems of agriculture, unemployment, and improvement
of national health.
It may, perhaps, be objected that, as it is,
we produce more milk than our people can, under present conditions,
buy. But the greater consumption of milk is now a national necessity
and means must be found to ensure it. Coming from a country where,
perforce, all milk must be sterilized by heating, the objections
to its sterilization do not appear to me to be so great as some
appear to think. It is true that this treatment does deprive it
of some of its nutritive quality, but of little that cannot be
made good by the adequate use of fresh vegetable foods; while
even in its sterilized state, it remains one of the best and cheapest
of all foodstuffs. Would it not be possible to sterilize milk
in large centres of its production and distribute it in suitably
sized sealed tins? Means have been found for the safe distribution
of inflammable petrol--a cheaper fluid than milk--can none be
found more efficient than the bottle for the house-to-house distribution
of contaminable milk? At present the housewife in the slums of
our great cities has often no place suitable in which to keep
a reasonable supply of milk; the sealed tin might help to solve
her difficulty, and a little knowledge help her to keep her supply
untainted. However this may be, sterilized milk is vastly better
than no milk, or than too little milk however pure it be. This
also must be said: the provision of fresh vegetables is complemental
to the provision of milk--the one is as much a national necessity
as the other.
A notable attempt has recently been made in
Bombay to improve the diet of the common people, and, after much
trial in schoolchildren, a balanced and very inexpensive diet
has been evolved that appears to satisfy physiological needs.
This has been achieved by the inclusion in it of whole cereal
grains, dried skim milk, soya bean, ground-nut, pulses and green-leaf
vegetables. So long as we in England insist on including in our
dietaries the more expensive, though not necessarily the most
nutritious foodstuffs, so long will a balanced diet be beyond
the reach of many whose means are limited. In a recent authoritative
report it is stated that meat is among the 'protective foods'.
It is probably so included because it is a rich source of 'good
protein' and of vitamin B2. But it is poor
in certain other essentials, and is, indeed, one of the foodstuffs
whose defects are made good by milk and green-leaf vegetables,
to which McCollum originally applied the term 'protective'. As
recently as 1934 he writes: 'There are avallable only two types
of protective foods, or foods which are so constituted as to make
good the defects of a white bread, meat, sugar and potato type
of diet. These are milk and leafy vegetables.' It is, to my mind,
inadvisable to include in the category of 'protective foods' a
wide range of expensive foodstuffs, some of which may be beyond
the reach of many of our people. By naming meat 'protective',
the impression is created that health depends on its inclusion
in the diet, which it does not. Far better is it to encourage
the use of inexpensive but none the less nutritious foodstuffs
(milk, cheese, herrings, wholemeal bread, vegetables, etc.), from
which satisfying and well-balanced meals can readily be made at
a relatively low cost. It is here that education is called for:
education not only in food-values but in the correct and inexpensive
selection and combination of foodstuffs.
Education
In this matter of education in the principles
of nutrition two of the great professions--the medical and the
scholastic--are in a position greatly to aid the endeavours of
Government in 'the building of an Al nation'. In regard to my
own profession I may repeat what I wrote fifteen years ago: 'It
is for us so to instruct ourselves that we may . . . use our newer
knowledge to the end that customs and prejudices may be broken
and a more adequate dietary secured for those under our care.'
'There can be no doubt', said the British Medical Journal,
in a leading article last year, 'but that this newer knowledge
of nutrition has placed in the hands of our profession a potent
weapon against disease-- a potent instrument in the promotion
of physical efficiency and wellbeing. It behoves us, therefore,
to become proficient in this knowledge, to apply it in the daily
course of our work, and to spread it by every means in our power.'
A special responsibility attaches to our medical schools in this
respect. 'At present medical students during the early years of
their course are given a few lectures and demonstrations dealing
with the physiology of nutrition, and perhaps carry out a little
laboratory work in this field; the subject is presented as a chapter
of physiology, and not as an integral part of preventive medicine.'
The authors of the League of Nations Report*, (*Nutrition
and Public Health, 1935.) from which we here quote, are
'far from suggesting that yet another speciality should be added
to the already congested medical curriculum'. But surely a subject
that is 'an integral part of preventive medicine' must in the
future be given a place in the medical curriculum commensurate
with its importance. In its teaching we must be content with no
half-measures. The student must have the opportunity to see with
his own eyes the havoc that is wrought in the various organs and
tissues of animals subjected to faulty nutrition of various kinds
and degrees. Only when the medical profession is itself so instructed,
can it play its proper part in the instruction of the public.
The next most important direction in which educational
effort is required is in the teaching of the elements of nutrition
to schoolchildren: 'We spend millions', said Lord Bledisloe in
a letter to The Times, (6th November, 1935.)
'on feeding the minds of the youth of the nation. Is it not time
that we spent a little (as an essential part of all school curricula)
on showing those young people how rationally and sensibly to feed
their bodies and those of their prospective progeny?' Here he
goes to the root of the matter, for it is only by the instruction
of youth that the faulty food habits of the people can ultimately
be altered and the desire created for those things that be good
from the nutritional point of view. This desire will lead to the
demand for them, may be translated into the greater production
of them and, perhaps, lead also to the return of many more people
to the land--a thing greatly to be desired. But to teach the children
the teachers must themselves be taught, and this requires the
adequate provision in all training colleges for prospective entrants
into the scholastic profession of facilities for the acquisition
of a thorough knowledge of the subject. These facilities do not,
so far as I can learn, now exist, or if existing they are not
adequate. Their provision is an urgent matter. It 'should set
the Board of Education thinking more deeply on a question which
vitally affects our national physique'.** (**Observer,
17th November, 1935.)
We have the assurance of Dr. Mary Swartz Rose,
Professor of Nutrition, Teachers' College, Columbia University,
than whom there is no greater authority on the teaching of nutrition
to boys and girls, that it is a subject to which they take readily
when it is properly taught. Her own book is a model of how such
instruction should be given. An essential part of this instruction,
as advocated by Professor Rose, is to give children the actual
experience of feeding animals (rats, guinea-pigs) on different
diets and to let them see for themselves the influence of food
on health and growth.
There are many other directions in which organized
effort is needed in regard to education in nutrition: the employment
of public health nutrition workers and of 'nutritionists' and
'dieticians', as is now so largely done in America; the teaching
of nutrition in schools of domestic science; education work among
rural populations; publications and propaganda. These matters
are all dealt with at length in a recent publication by the health
organization of the League of Nations.*** (***Nutrition
and Public Health, IV, February, 1935.) But behind
all such effort there is the dark cloud of economic conditions
that make it difficult, if not impossible, for large numbers of
our people to procure diets that will satisfy their physiological
needs. Happily there are signs that this cloud is lifting, and
there is no lack of evidence both of desire and of effort to ensure
a better way of life for the less fortunate amongst us. Until
this cloud is dispelled the distribution of relief in kind might
well be resorted to. Collective feeding has much to recommend
it, both for workers and for unemployed.
In dealing with a subject so vast as nutrition,
the lecturer, perforce, confines himself to certain aspects of
it--usually those that have come within his own experience. For
my own part, my interests have lain in the direction of learning
what I could of the relation of faulty food to nutrition and of
both to health and disease; and out of this desire to learn there
has come the desire to spread such knowledge of the subject as
we already possess. It has been my endeavour, during these lectures,
to convey this knowledge to you, in the hope that with understanding
there may come belief. Belief that the continued use of properly-constituted
food, from the earliest period of development onwards throughout
life, is the surest means we have of acquiring and maintaining
that condition of body--good health--which is 'the vital principle
of bliss':
This Life-joy, like the breath-kiss of the all-ambient air
unnoticed til the lack of it bring pain and death,
is coefficient with the untramlel'd energy
of nativ faculty, and the autometric scale
of all functions and motions, . . .
it is the lordly heraldry of the banner'd flower,
in brutes the vaunt of vigour and the pose of pride,
their wild impersonation of majesty; and in man
the grace and ease of health alike in body and mind,
that right congruity of his parts, for lack whereof
his sanity is disabled, main'd and compromised.*
ROBERT BRIDGE
*From The Testament of Beauty, by Robert Bridges (Clarendon Press, Oxford).