The Planning of the Diet

PRACTICAL CONSIDERATIONS WHICH SHOULD GUIDE IN THE PLANNING OF THE DIET

In the preceding chapters there were presented
data, which have been obtained by biological
methods, concerning the special dietary properties
of the several classes of natural food-stuffs, which
enter into the diets of man and animals. It is evident
from the experiments described that a diet may fur-
nish an abundance of protein and energy, and may
be easy of digestion, and may furnish a wide variety
and include several seeds or products derived from
these, together with tubers, roots and meats, and
may be highly acceptable to the human palate and
yet fail utterly to support satisfactory nutrition.
In the light of such facts, it becomes apparent that
a chemical analysis of a food-stuff throws no light
whatever upon certain aspects of its dietary prop-
erties. It is only by biological methods that we can
arrive at principles which can serve as a safe guide as
to the method of procedure by means of which safe
diets can be planned. In the present chapter will be
discussed a number of questions which always arise
in the minds of those who wish to apply the new
knowledge to the planning of a suitable dietary
regime.

130

THE PLANNING OF THE DIET 131

It should be understood that it is neither necessary
or desirable that we should abandon the customary
classification of food-stuffs on the basis of chemical
composition. We must have a language of nutrition,
and consider foods on the basis of their protein,
carbohydrate, fat, water and mineral content, as we
have always done. We should be familiar with the
quota of energy available from the different types of
foods. We must, however, take into consideration
certain facts which have not hitherto been considered,
and concerning which a chemical analysis gives no
information.

One of the outstanding results of modern research
in nutrition is the great difference in the biological
values of the proteins from different sources. In a
general way this is appreciated by all well informed
teachers of the present day, but many are still in
need of clearer distinctions regarding what data in
the literature are capable of direct application to
practical nutrition, and what are of such a nature
that they cannot be so applied. No lack of apprecia-
tion is intended of data of the latter type, for they
may have, and indeed frequently have a value of
the first importance to the investigator in this field.
As an example may be cited the laborious studies
through which the airino-acids became known, and
the data yielded by such method of analysis of the
proteins as those of Fischer and of Van Slyke. Im-
portant as are these results in making possible fur-
ther progress, they are not of such a character that

132 THE NEWER KNOWLEDGE OF NUTRITION

they can be applied, as has been frequently at-
tempted, in making deductions concerning com-
parative food values. It is, however, through such
studies that we have arrived at a satisfactory working
hypothesis concerning the nature of the proteins,
and have become able to appreciate why the proteins
have different values in nutrition. Our analytical
methods do not make possible an approximately
quantitative determination of more than a third of
the total number of the digestion products of the
proteins. An attempt to utilize the figures for the
yield of this or that amino-acid by one or another of
the proteins, as evidence of the comparative values
of the proteins themselves, or of the food-stuffs from
which they are derived, will lead to entirely fallacious
deduction.

Such data as are tabulated in the literature for the
yields of the different amino-acids, make the pea
and bean proteins appear superior to those of the
cereal grains. McCollum and Simmonds have re-
ported a long series of experiments with diets so
planned that they were adequate in all respects,
and the protein content was derived entirely from a
single seed. The amount of protein in the diet was
varied so as to find in one series what was the lowest
per cent of protein in the food mixture which would
just maintain a grown rat over a period of several
months without loss of body weight, and in another
series, the minimum amount of protein was deter-
mined which would induce in the young, half normal

THE PLANNING OF THE DIET 133

and full normal rate of growth respectively. The
data regarding the values of several of the more im-
portant seed proteins for maintenance are of great
interest. Rats can be maintained in body weight
on suitably constituted diets containing 4.5 per cent
of oat protein, or of millet seed protein; on 6 per cent
of maize, rice or wheat proteins ; on about 8 per cent
of flax-seed protein, whereas it requires about 11 to
12 per cent of the proteins of the pea or the bean to
accomplish the same result.

Chemical analysis shows the proteins of the pea
and bean to contain all the known amino-acids,
and none of these are present in excessive or in min-
imal quantities, whereas the wheat and maize pro-
teins yield excessive amounts of one of them in par-
ticular. Glutamic acid, one of the digestion products
of proteins, is present in the proteins of the muscle
tissues of animals, in the case of no less than half a
dozen species, to the extent of twelve to fourteen
per cent. The same acid is present in the two prin-
cipal proteins of the wheat kernel to the extent
of nearly 40 per cent, and in the principal protein
of the maize kernel to the extent of about 25 per
cent. These proteins show other differences in com-
position which led to the belief that they were of
relatively low biological value for growth, before
they were studied satisfactorily by appropriately
planned feeding experiments, all of which have con-
firmed this view. The observation that the split
pea and navy bean proteins are of much less value in

134 THE NEWER KNOWLEDGE OF NUTRITION

nutrition came therefore as a distinct surprise, since
these results were not what were expected, in view
of the tabulated yields of the several amino-acids
shown by the most careful chemical analysis. The
data obtained by properly planned feeding experi-
ments are highly reliable, those from the chemical
analysis very unsafe, from which to draw deductions.
It should be understood that these values for the
proteins of the seeds apply only to the proteins of
the single seed when fed as the sole source of protein.
When fed in mixtures of two or more proteins having
individually low values for the support of growth, they
may mutually make good each other's amino-acid
deficiencies, and form a mixture which is better than
either constituent when fed singly. Since this was
to be expected, McCollum, Simmonds and Parsons
have made many feeding trials with simple com-
binations of two seeds, such as two cereal grains, one
cereal and one legume seed (pea, bean) ; one seed and
one leaf, etc., as the sole source of protein in the diet,
and have sought to find which are the most fortunate
combinations of the most important food-stuffs for
the production of protein mixtures of high biolog-
ical values for the support of growth. These trials
have shown that, while such mixtures of proteins are
superior to the individual foods fed separately as
sources of protein, it has not been found possible to
obtain protein mixtures from vegetable sources which
even approximate the value of milk proteins, for the
support of maintenance or growth.

THE PLANNING OF THE DIET 135

The nitrogen-containing compounds of the potato
have been lauded by several investigators as being of
extraordinary value as a source of protein. Mc-
Collum, Simmonds and Parsons have studied the
proteins of the potato, both for maintenance and
growth, in experiments in which this tuber served as
the sole source of protein, and all its dietary defi-
ciencies were made good by suitable additions of
purified food substances. These all indicate that
when fed as the sole source of protein, the nitrogen
compounds of the potato have a distinctly lower
value than have the proteins of the cereal grains,
oat, wheat, rice and maize.

Enough has been said regarding the great dif-
ferences in the values of the proteins from different
sources, to make it clear that it is impossible to say
how much protein the diet should contain without
having a knowledge of the values of the proteins
which the diet contains. Chemical methods of
analysis are not yet sufficiently perfected to throw
any appreciable light on the values of the mixtures
of proteins which occur in our natural foods.

The great attractiveness of the "vitamine" hy-
pothesis of Funk, as an explanation for all the states
of malnutrition which are referable to faulty diet,
has led, in recent years, to much discussion of the
question of the possible deterioration of foods during
cooking, canning and drying. The demonstration
by McCollum and his co-workers that there are but
two unidentified dietary essentials, and but two diet-

136 THE NEWER KNOWLEDGE OF NUTRITION

ary " deficiency " diseases, due respectively to a
shortage of one or the other of these substances, fat-
soluble A and water-soluble B, and that there are no
"growth determinants' 9 unnecessary for the mainte-
nance of health in the adult, does not minimize the
importance of this subject. The work of a number
of investigators has shown that the water-soluble B,
the protective substance against beri-beri, is readily
destroyed when an excess of even such weak alkalies
as soda are added to the food, suggests that this
substance may be of an unstable character.

Osborne and Mendel 1 have shown that butter
fat may have a blast of steam passed through it for
two hours and still retain its peculiar growth-pro-
moting properties, due to the presence of the fat-
soluble A. This observation is in harmony with
those of McCollum and Davis, that heating butter
fat at the temperature of boiling water does not
affect its peculiar dietary value. It is apparent,
therefore, that any conditions to which milk fats are
liable to be subjected during the cooking of foods
will not greatly alter its value as a source of the fat-
soluble A. McCollum and Simmonds have recently
(unpublished data) tested a sample of butter fat
prepared from evaporated milk, furnished to them
by Dr. Lucius P. Brown of New York City, and have
found it very effective in relieving the xerophthalmia
in rats, brought on by the lack of the fat-soluble A
in their diets. It appears, therefore, that there is no
great deterioration in the quality of milk fats brought

THE PLANNING OF THE DIET 137

about by the processes of removal of water in the
preparation of condensed or evaporated milks. They
have likewise shown, as have also Osborne and Men-
del, that dried milks still contain the fat-soluble A
in abundance. There can be no serious objection to
the use of dried or canned milks on the basis of their
value with respect to this dietary essential.

The situation is likewise quite clear with respect
to the ordinary dried foods. Leaves such as celery
tops and those of the immature alfalfa plant, when
dried in the ordinary way, are still good sources
of the fat-soluble A. The alfalfa leaves were dried
in the sun and the celery tops by artificial heat in a
current of air after a preliminary treatment with
steam.

McCollum and Davis 2 have pointed out that
wheat germ can be moistened and heated in an auto-
clave at fifteen pounds pressure for an hour or more
without any extensive destruction of the water-
soluble B, and McCollum, Simmonds and Pitz 3 have
subjected soaked navy beans to similar treatment
without causing any great deterioration with respect
to this dietary factor. This treatment is comparable
to that to which fruits and vegetables are subjected
when processed in canning, and shows that the wide-
spread belief that canned foods have lost these diet-
ary essentials is, at least, generally without foun-
dation. The cooking of beans or greens with the
addition of soda, which is a common practice, may
cause the destruction of one or both of the unidentified

138 THE NEWER KNOWLEDGE OF NUTRITION

dietary essentials. At least in the case of the water-
soluble B, this will probably be true if sufficient
soda is added to render the food alkaline. The use
of soda in biscuit making will, according to Voegtlin,
and Sullivan 4 cause the destruction of the water-
soluble B, for they found that corn meal cooked with
soda was no longer effective in causing the "cure"
of beri-beri in pigeons.

In this connection it should be borne in mind that
our ordinary foods all contain several times the
amount of the water-soluble B which is necessary
for the maintenance of growth and health in animals.
There seems to be no valid reason why, if it is neces-
sary for culinary purposes, to use soda in the cook-
ing of a few foods, the practice should be discontinued.
If the diet is so planned as to furnish a suitable quota
of milk, and of cereals and other foods which are not
so treated as to destroy the water-soluble B there is
no danger of a shortage of this substance in the diet.
It is now well demonstrated that with the diets employed
in Europe and America there is no such thing as a
u vitamins 97 problem other than that of securing an
adequate amount of the substance fat-soluble A. Seeds
and their products, tubers, roots and meats in the
amount in which they are ordinarily consumed, do
not furnish enough of this substance for the mainte-
nance of an optimum state of well-being. Diets Com-
posed of these substances exclusively, may, when
their other deficiencies are corrected, contain enough
of the fat-soluble A to induce fairly good growth to

THE PLANNING OF THE DIET 139

nearly the full adult size, and may long prevent the
development of xerophthalmia. They do not supply
enough of it to support maximum vigor over a long
period, and fall short of the amount necessary under
the special conditions involved in pregnancy and
lactation.

There is a wide-spread belief that wheat is superior
to the other cereals as a food. There is no experi-
mental evidence that this is true. Rye, barley, oats
and maize resemble wheat very closely in their diet-
ary properties, and it is safe to say that these can
entirely replace wheat in the diet of children, adults
and invalids without the least detriment to health.
Those who have become accustomed to the use of
wheat bread, are attached to it principally because
of habit. Dietary habits become very firmly fixed
and are hard to break away from. Millions in the
Orient are greatly attached to rice as a food, and
feel that they cannot live without it, whereas, we in
America cannot bring ourselves to eat liberally of it
in the simple and unappetizing form in which it is
entirely acceptable in the Oriental. The Italian
feels that no diet is satisfactory unless it contains
macaroni. Garlic and other flavors which appeal to
the appetite of certain peoples are disliked by others.
These prejudices and many others are not expressions
of physiological need, but are purely demands for
something to which we have become accustomed.
When properly cooked, cornmeal, oats and other
cereals have never been shown to produce digestive

140 THE NEWER KNOWLEDGE OF NUTRITION

disturbances. Reports that the people of Belgium,
when restricted to the scanty fare which could be
furnished them after the occupation of their territory
by Germany, suffered from digestive disturbances
from eating corn bread, are not to be taken as evi-
dence that the corn products were in themselves re-
sponsible for the trouble. They were the sequel of
an inadequate diet which impaired the vitality.
Experiments have been described, showing that
bolted wheat flour is inferior to whole wheat. 5 If
two pigeons are fed whole wheat and bolted flour re-
spectively, while a third is allowed to fast, the first
will remain in a state of apparent health for several
weeks, the second will lose weight and die earlier than
the fasting one. This does not mean that bolted flour
is poisonous, but only that it is a more incomplete
food than whole wheat. The pigeon which is fed
whole wheat will succumb in the course of time, for
whole wheat is not a complete food. The pigeon
which fasts gradually wastes away, but slowly, be-
cause all the tissues decrease in volume and its physi-
ological processes slow down. The bird which is fed
the bolted flour dies earlier than the fasted one, be-
cause the burden of digesting and metabolizing a
liberal intake of food requires that his metabolic
processes go on at a rapid rate. When this demand
is made upon it and its diet is so incomplete that
there can be no repair of its wasted tissues, it wears
out the more quickly. Such demonstrations do not
constitute an argument against the use of wheat flour

THE PLANNING OF THE DIET 141

as a food. In so far as the latter supplies protein,
energy and inorganic salts, it is a good food. What
we should realize is that none of our vegetable foods
or the meats are complete and ideal foods. Some are
more deficient than others, and their deficiencies are
not all alike. Satisfactory nutrition is to be attained
only through the employment of the right combi-
nations of foods, and in such proportions as will in-
sure that the resulting diet will be properly con-
stituted. We should accept our natural foods for
what they are, and make proper use of them, rather
than condemn this or that one because it is lacking
in some respect.

It is fallacious reasoning to attempt to compare
the money value of certain foods with certain others.
We may safely compare the cost of the cereal grains
or the legumes with each other, or with the tubers
such as the potato or the sweet potato, or with the
root foods. It is not possible to compare the cost of
any of these with milk or the leafy vegetables such
as cabbage, cauliflower, Swiss chard, collards,
Brussel sprouts, onions, lettuce, celery tops, spinach,
turnip tops and other leaves employed as greens.
Milk and the leafy vegetables are to be regarded as
protective foods. In some degree eggs are to be con-
sidered in the same class. Milk and the leafy vege-
tables should be taken in liberal amounts. The
leaves should not be regarded as foods of low value
because their content of protein, fat and carbohy-
drate is low, and the content of water high. When

142 THE NEWER KNOWLEDGE OF NUTRITION

compared on the basis of chemical composition they
appear inferior to seeds, but they have a peculiar
value in their high content of fat-soluble A and of
mineral elements, which makes them stand in a
class by themselves among the vegetable food-stuffs.

No thorough studies of the dietaiy properties of
fruits have yet been made, but from their known
chemical composition and biological functions as
storage organs, their proper place in the diet can be
predicted. They are good sources of mineral salts
and of energy-yielding foods, the sugars. They are
highly palatable and exert a favorable influence on
the excretory processes of the kidneys and the in-
testine. Their liberal use in the diet should be en-
couraged.

Owing to the present shortage of certain food-
stuffs, there has been a tendency to consider the in-
troduction of certain new products hitherto not
generally employed in a large way as human foods,
and to extend their use by extolling their virtues.
Conspicuous among these are the peanut press cake,
which remains after the oil is extracted by pressure,
the soy bean and cottonseed flour. The latter prod-
uct represents a portion of the cottonseed which is
prepared by first removing the oil, and afterward
grinding and bolting to obtain a product free from
hulls and fiber. These movements directed toward
the utilization of all our food resources are laudable,
but the information which is disseminated con-
cerning these products by their enthusiastic pro-

THE PLANNING OF THE DIET 143

moters is not in all cases accurate and sufficiently
complete to serve as a safe guide to the user. They
are extolled in the time-honored fashion as foods
rich in protein and energy, but their exact place in
the dietary is not sufficiently emphasized.

There can be no doubt that the peanut is a whole-
some food, and can be used to advantage in the diet
of man in moderate amounts. It is likewise a good
source of protein of fairly good quality. The same
can be said of the soy bean. The proteins of neither
of these have extraordinary values. That there are
no proteins of extraordinary values in the seeds of
plants yet studied, is apparent from a critical and
unprejudiced inspection of all of the extensive ex-
perimental data available. The point to be em-
phasized in this connection, is that these are seed prod-
nets, and have in a general way the peculiar dietary
properties common to seeds. Their place in the diet
is therefore clear. They may be employed in moder-
ate amounts along with other seeds and seed prod-
ucts, provided that they are supplemented with
sufficient amounts of the protective foods, milk and
the leafy vegetables.

With respect to cottonseed products the case is
somewhat different. The cottonseed has long been
known to contain something toxic to animals, and ex-
perience has taught that cottonseed meal, a product
containing the hulls, cannot be fed liberally to animals
without disastrous results. Withers and Carruth 6
have conducted extensive investigations regarding

144 THE NEWER KNOWLEDGE OF NUTRITION

the nature of the toxic constituent, and have iso-
lated it as a substance to which the name gossypol
has been given. It is destroyed by oxidation, and
by appropriate heat treatment, and some cotton-
seed products are much less poisonous than others,
because of the special treatment which they have
received. The author has fed cottonseed flour to a
large number of animals, and is convinced that it
should not be employed in the human dietary in very
liberal amounts. If the diet is appropriately con-
stituted with respect to its content of the protective
foods, cottonseed flour which has been thoroughly
cooked, will, when used in moderation, be found to be
a useful food-stuff. The data available emphasize the
need for further careful studies to show how much
heat treatment is necessary to render cottonseed
flour harmless. Such knowledge, when available,
will make possible the standardization of commercial
products, and will make possible the utilization of
this vast food resource.

The paramount importance of maintaining and
of increasing the production of milk makes it neces-
sary to utilize a large amount of protein-rich foods in
the dairy industry. The wisest plan is to extend the
use of peanut, soy bean and cottonseed products for
milk production. The cow produces much of her
milk from coarse feeds, not suitable for human con-
sumption, but requires liberal protein-rich supple-
ments in addition. Greater emphasis should be laid
upon the wisdom of a more liberal purchase of milk

THE PLANNING OF THE DIET 145

by the public. This would insure the best utiliza-
tion of these protein-rich products which have not
as yet in many quarters found extensive use as hu-
man foods. Experimental data seems to have es-
tablished that the proteins of the peanut and the soy
bean are of better quality than those of the pea or
the navy bean. From the author's studies of the soy
bean it appears that its proteins have about the
same quality as those of the cereal grains, but it con-
tains three times as much protein as the latter. Its
content of fat-soluble A is such that a mixture of
soy bean and starch which has the same protein con-
tent as the wheat kernel, probably has about the
same dietary properties as has wheat with respect to
these two dietary factors. There is no reason why
the peanut and soy bean should not be employed to
a greater extent as human foods, but it should be
kept in mind that good use is already being made of
these products in the feeding of dairy cows, and that
if they are withdrawn from this application for use
as human foods directly, it will not be easy to find
something to take their place in the dairy industry.
Several writers have pointed out that these seeds
contain the fat-soluble A, and have exhibited growth
curves which indicate that animals have taken one of
these seeds properly supplemented so as to correct
its deficiencies, and have been able to grow, to ap-
proximately the full adult size without the addition
of more of this dietary essential. The reader is left
with the impression that the peanut, soy bean and

146 THE NEWER KNOWLEDGE OF NUTRITION

cottonseed may serve as an adequate source of fat-
soluble A. This impression is an unfortunate one,
for it is certain that even with diets which are com-
posed largely of these seeds, the content of this sub-
stance is below the optimum, and in the amounts in
which they are likely to enter into the human diet,
they will never serve as a substitute for the pro-
tective foods. In the enthusiastic application of the
biological method for the analysis of food-stuffs, by
those with little experience, after its description by
McCollum and Davis in 1915, 7 hasty conclusions
have been drawn in a number of instances. Mc-
Collum and Simmonds have emphasized the necessity
of observing over long periods, such animals as are
able to grow at about the normal rate and produce
a few young and rear them, when confined to ex-
perimental diets. In many instances it is foimd that
the interval between litters is too long, or the mor-
tality of the young abnormally high, the time neces-
sary to bring the young to the weaning stage too
long and the signs of old age appear too early, in
animals which during the early part of the reproduc-
tive period appeared to be nearly normal in all re-
spects. They have reached the conclusion that it is
necessary to observe the behavior of the second
generation when confined to the diet of the parent
before drawing final conclusions concerning the
quality of a diet. In many instances lack of vitality
is first observed in the inability of the offspring to
develop normally on a diet which would, in the early

THE PLANNING OF THE DIET 147

life of the parent, have been considered entirely sat-
isfactory. When observations are extended in this
way, it becomes apparent that lung infections very
frequently terminate the lives of the animals, whose
diets are faulty in some degree, but not so faulty as to
make their effects strikingly apparent.

From many questions asked by the public the au-
thor has gained the conviction that faulty deductions
have been drawn by others from experimental
studies, which would lead the inexperienced reader
to conclude that by the use of any seed products, or
other food-stuffs of vegetable origin, whose func-
tions are those of storage organs, that diets can be
prepared which are so satisfactory as to make it
feasible to dispense with a liberal intake of the food-
stuffs which we have designated as protective foods.
These can be shown to be based upon failure to fully
appreciate what constitutes a satisfactory demon-
stration of the adequacy of a diet. Mankind will do
well to avoid such diets which may, as Golderger
has suggested, place one in "a 'twilight' zone within
which a very slight change in any of the dietary
components may cause an important shift of bal-
ance. ,,

McCollum and Simmonds have reported many
experiments with diets so planned as to be satisfac-
tory in that all the factors but one afforded a liberal
margin of safety in offering an abundance over the
minimal requirements of the animal, 8 and the re-
maining one so adjusted as to represent the actual

148 THE NEWER KNOWLEDGE OF NUTRITION

minimum on which the animal can subsist over a
considerable period. In this way it has been possible
to demonstrate that the amount of fat-soluble A
may be reduced to a certain minimum without the
development of xerophthalmia, whereas the same
intake of this substance will not prevent the charac-
teristic eye trouble when the intake of protein is
likewise sufficiently lowered. They have been able
to so adjust the components of the diet as to make
it possible to relieve xerophthalmia either by in-
creasing the content of protein or of fat-soluble A
in the food, although it is the lack of the latter which
is the specific cause of the disease. Such observations
make it evident that it is impossible to say what is
the safe minimum of any dietary factor, unless the
biological values of all the other essential constituents
of the diet are known. This represents an actual
accomplishment of planning a diet which brings
the animal into the "twilight" zone, where small
shifts in the quality of the diet with respect to any
factor may either distinctly stabilize the metabolic
processes of the animal, or may lead to the develop-
ment of a distinct pathologic state.

Their studies with the types of diets just described,
lead them to the conclusion that it is unwise to
approach very closely the physiological minimum
with respect to any dietary factor. Liberal consump-
tion of all of the essential constituents of a normal diet,
prompt digestion and absorption and prompt evacuation
of the undigested residue from the intestine before ex-

THE PLANNING OF THE DIET 149

tensive absorption of products of bacterial decomposition
of proteins can take place } are the optimum conditions
for the maintenance of vigor and the characteristics
of youth. Such a dietary regime can be attained only
by supplementing the seed products, tubers, roots
and meat, which must constitute the bulk of the
diet of man, with the protective foods, milk and the
leafy vegetables.

The results of the study of several representatives
of each of the different classes of food-stuffs has led
the author to the conclusion that, while it is not de-
sirable to relegate to the background any of the
fundamental knowledge of food-stuffs which can be
obtained by chemical methods, and by respiration
and digestion studies, the fundamental basis of nutri-
tion can best be imparted to the public through the
adoption of a biological classification of the natural
food-stuffs on the basis of their function. Foods
other than milk and eggs of both animal and veg-
etable origin may be arranged into groups according
to whether they represent principally, functioning
active protoplasm, or deposits of reserve food mate-
rial, or in animal tissues, highly specialized contract-
ile tissues. From their biological function their
dietary properties can be fairly accurately predicted.
This idea, together with the knowledge that milk,
eggs and the leafy vegetables, the protective foods,
are so constituted as to correct the dietary deficiencies
of the seeds, tubers, roots and meat, should form
the central idea in the teaching of the science of

150 THE NEWER KNOWLEDGE OF NUTRITION

nutrition. It should be emphasized that the diet is
a relatively complex thing, and that none of the
essential constituents can be ignored in its planning,
but that the observance of certain general rules of
procedure will insure that any faults in the diet
will be reduced to a minimum.

It is of special moment at this time to emphasize
the importance of the dairy industry in its relation
to the public health. Mankind may be roughly
classified into two groups. Both of these have de-
rived the greater part of their food supply from
seeds, tubers, roots and meat, but have differed in
respect to the character of the remainder of their
diets. One group, represented by the Chinese,
Japanese and the peoples of the Tropics generally,
have employed the leaves of plants as almost their
sole protective food. They likewise eat eggs and
these serve to correct their diet. The other group
includes the peoples of Europe and North America
and a few others. These have likewise made use
of the leaves of plants, but in lesser degree, and have,
in addition, derived a very considerable part of their
food supply from milk and its products.

Those peoples who have employed the leaf of the
plant as their sole protective food are characterized
by small stature, relatively short span of life, high
infant mortality, and by contended adherence to the
employment of the simple mechanical inventions of
their forefathers. The peoples who have made lib-
eral use of milk as a food, have, in contrast, attained

THE PLANNING OF THE DIET 151

greater size, greater longevity, and have been much
more successful in the rearing of their young. They
have been more aggressive than the non-milk using
peoples, and have achieved much greater advance-
ment in literature, science and art. They have
developed in a higher degree educational and polit-
ical systems which offer the greatest opportunity
for the individual to develop his powers. Such
development has a physiological basis, and there
seems every reason to believe that it is fundamentally
related to nutrition.

In the United States, we have in the past de-
rived no less than 15 to 20 per cent of our total
food supply from the products of the dairy. The
investigations of recent years have thrown a new
light on the importance of this increment of our diet.
It has become evident that milk is the greatest
factor of safety in our nutrition, and it is certain
that we could not have accomplished what we have,
had we dispensed with milk as a food.

The situation of the dairy industiy is at the present
time precarious. The cost of feeding-stuffs and of
labor have enormously increased during the last
few years, and consequently the cost of milk produc-
tion. Advance in the cost of milk to the consumer
has been made unavoidable. Every advance in the
price has, however, met with great resistance by the
public, and with each rise there has been a distinct
drop in the amount purchased. The milk delivered
in the city of Chicago has fallen off from about a

152 THE NEWER KNOWLEDGE OF NUTRITION

million and a quarter quarts daily to about seven
hundred thousand quarts, within a year. Similar
reductions in sales have occurred almost everywhere
in the Eastern half of the country, solely because of
the rise in price. This has resulted in the discourage-
ment of producers everywhere, and in a movement
toward the reduction of the number of dairy cows.

There can be no doubt that there is great lack of
knowledge by the people generally as to the impor-
tance of milk and other dairy products in the diet.
There is no substitute for milk, and its use should
be distinctly increased instead of diminished, re-
gardless of cost. Every possible means should be
employed to reduce the cost of distribution. The
necessity for the liberal use of milk and its products
both in the diets of children and adults should be
emphasized in order to stem the ebbing tide of its
production. It has been pointed out that the value
of milk as a food cannot be estimated on the basis
of its content of protein and energy. Even when
measured by this standard it compares most favor-
ably with other foods, but it has a value as a protect-
ive food, in improving the quality of the diet, which
can be estimated only in terms of health and effi-
ciency.

An examination of any large groups of people in
the cities, will show that where there is a high mor-
tality from tuberculosis, milk is not being used to
any great extent, and in any large group where
milk purchases are large this disease is not a menace.

THE PLANNING OF THE DIET 153

It is well known N that in institutions where tuber-
culosis is successfully treated milk forms the prin-
cipal article of the diet of the inmates. This has
resulted from clinical experience. There is no other
effective treatment for this disease than that of
providing fresh air, insisting upon rest and of height-
ening the body's powers of resistance through the
liberal use of milk for the correction of faults which
the diet will inevitably have when it consists too
largely of seed products, tubers, roots and meats.
The importance of diets of this character in the
etiology of tuberculosis, has not hitherto been
appreciated. In the light of facts presented in the
previous chapters of this book, there can be no
reasonable doubt that the importance of poor
hygienic conditions and of poor ventilation have
been greatly over-estimated, and that of poor diet
not at all adequately appreciated as factors in pro-
moting the spread of this disease. Milk is just as
necessary in the diet of the adult as in that of the
growing child. Any diet which will not support
normal development in the young will not support
optimum well-being in the adult. Milk is our greatest
protective food, and its use must be increased. The
price must be allowed to go up, so long as the cost
of production makes it necessary, and up so far as is
essential to make milk production a profitable busi-
ness. Unless this is done, the effects will soon be-
come apparent in a lowering of our standards of
health and efficiency.

192 BIBLIOGRAPHY

16. Funk, C: J. State Med., 1912, xx, 341; Biochem. Bull.,

1915, iv, 304.

17. McCollum and Davis: Jour. Biol. Chem., 1915, xxiii, 181.

18. McCollum and Davis: Jour. Biol. Chem., 1915, xxiii, 231.

19. McCollum, E. V., and Kennedy, C: Jour. Biol. Chem.,

1916, xxiv, 491.

20. Osborne, T. B., and Mendel, L. B.: Jour. Biol. Chem.,

1913, xvi, 431.

Chapter II

1. McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1917,

xxix, 341.

2. Smith, Theobold: Bureau of Animal Industry, Bacilli in

Swine Disease, 1895-1896, 172.

3. Hoist, A., and Frolich, T.: Z. Hyg. u. Infektionskrankh,

1913, lxxv, 334.

4. McCollum and Pitz: Jour. Biol. Chem., 1917, xxxi, 229.

5. McCollum and Simmonds: Jour. Biol. Chem., 1917, xxxii,

181.

6. McCollum and Simmonds: Jour. Biol. Chem., 1918,

xxxiii, 55.

7. Hart, E. B., McCollum, E. V., Steenbock, H., and Hum-

phery, G. C: Wise. Agric. Expt. Sta. Research Bull.,

17, 1911.
Hart and McCollum: Jour. Biol. Chem., 1914, xix, 373.
McCollum and Davis: Jour. Biol. Chem., 1915, xxi, 615.
McCollum, Simmonds and Pitz: Ibid, 1916-1917, xxviii,

211.

8. Hart and McCollum: Jour. Biol. Chem., 1914, xix, 373.
McCollum, Simmonds and Pitz: Ibid, 1916, xxviii, 153.

9. McCollum, E. V., Simmonds, N., and Parsons, H. T.:

Unpublished data.
10. McCollum, E. V.: Jour. Am. Med. Assn., 1917, lxviii, 1379.
Harvey Lecture Series 1916-1917 — also — Unpublished
data.

BIBLIOGRAPHY 193

11. McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1917,

xxix, 521.

12. McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1917,

xxx, 13.

Chapter III

1. Slonaker, J. R.: Leland Stanford Junior University, Pub.

Univ. Series, 1912.

2. McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1917,

xxx, 13.

3. McCollum, Simmonds and Pitz: Am. Jour. Physiol., 1916,

xliv, 333.

4. Eward, J. M.: Proc. Iowa Acad. Sci., 1915, xxii, 375.

5. Loeb, J.: The Dynamics of Living Matter, New York,

1906.

6. Howell, W. H.: Am. Jour. Physiol, 1899, ii, 47; 1902, vi,

181.

Chapter IV

1. McCollum, E. V.: Jour. Biol. Chem., 1914, xix, 323.

2. McCollum and Simmonds: Jour. Biol. Chem., 1917, xxxii,

347.

3. McCollum and Davis: Jour. Biol. Chem., 1915, xx, 415.

4. McCollum, Simmonds and Parsons: Unpublished data.

Chapter V

1. McCollum and Kennedy: Jour. Biol. Chem., 1916, xxiv,

491.

2. Osborne and Mendel: Jour. Biol. Chem., 1913, xvi, 431.

3. McCollum and Simmonds: Jour. Biol. Chem., 1917, xxxii,

347.

4. McCollum, Simmonds and Parsons: Unpublished data.

5. Herdlika, A, : Bulletin 34, Bureau of American Ethnology.

194 BIBLIOGRAPHY

6. Mori, M. : Jahrb. Kinderheilk, 1904, lix, 175.

7. Bloch, C. E.: Ugeskruft fiir Laeger, 1917, lxxix, 349, cited

from Jour. Am. Med. Assn., 1917, lxviii, 1516.

8. Czerny, A. and Keller, A. : Des Kindes, Leipsic, 1906, pt.

2,67.

9. Little, A. D.: Jour. Am. Med. Assn., 1912, lviii, 2029.

10. Walcott, A. M.: Jour. Am. Med. Assn., 1915, lxv, 2145.

11. Eijkman, C: Arch. f. Hyg., 1906, lviii, 150.

Arch. Path. Anat., 1897, cxlviii, 523.

12. Funk, C: Lancet, London, 1911, ii, 1266.

13. Funk and Macallum: Jour. Biol. Chem., 1915, xxiii, 419.

14. Williams, R. R.: Jour. Biol. Chem., 1916, xxv, 437; 1916,

xxvi, 431 ; 1917, xxix, 495.

15. Jackson, L., and Moore, J. J.: Jour. Infect. Dis., 1916, xix,

478.

16. McCollum and Pitz : Jour. Biol. Chem., 1917, xxxi, 229.

17. Hess, A. F.: Am. Jour. Dis. of Children, 1917, xiv, 337.

18. Goldberger, Joseph: Jour. Am. Med. Assn., 1916, lxvi, 471.

19. Jobling, J. W., and Peterson, W.: Jour. Infect. Dis., 1916,

xviii, 501.

20. Thompson-MacFadden Commission, Siler, J. F., Garri-

son, P. E.,and McNeal, W. J.: Archiv. Int. Med. Oct.

1914, p. 453; Journ. Amer. Med. Assn. Sept. 26, 1914,
p. 1090.

21. Goldberger, Joseph: Public Health Reports, November 17,

1916, pp. 3159-3173.

22. Goldberger, Joseph: Public Health Reports, Nov. 12,

1915, p. 3.

23. Chittenden, R. H. , and Underhill, F. P. : Am. Jour. Physiol.,

1917, xliv, 13.

24. McCollum, Simmonds and Parsons: Jour. Biol. Chem.,

1918, xxxiii, 411.

25. McCollum and Simmonds: Jour. Biol. Chem., 1917,

xxxii, 29.

26. Hess, A. F. : Jour. Am. Med. Assn., 1918, ixx, 900.

BIBLIOGRAPHY *195

Chapter VI

1. McCollum and Simmonds: Am. Jour. Phys., 1918, xlvi,

275.
McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1916,
xxvii, 33.

2. Osborne and Mendel: Jour. Biol. Chem., 1915, xx, 379.

3. Andrews, V. L.: Philippine Jour. Science, Series B, 1912,

vii, 67.

4. Babcock, S. M.: Twenty-Second Annual Report of Wis-

consin Experiment Station, 1905, 129.

5. Eckles, C. H., and Palmer, L. S. : Missouri Agric. Expt.

Station Research Bull., 25, 1916.

6. Ducaisne, E.: Gaz. Med., Paris, 1871, 317.

Chapter VII

1. Osborne and Mendel: Jour. Biol. Chem., 1915, xx, 381.

2. McCollum and Davis: Jour. Biol. Chem., 1915, xxiii, 247.

3. McCollum, Simmonds and Pitz: Jour. Biol. Chem., 1917,

xxix, 521.

4. Sullivan, M. X., and Voegtlin, C. : Jour. Biol. Chem., 1916,

xxiv, xvi.

5. Simpson and Edie: 1911-12, Ann. Trop. Med. and Parasit.,

v, 321.
Ohler: Jour. Med. Research, 1914, xxxi, 239.

6. Withers and Carruth: Jour. Agric. Research, .1915, v, 261.

Jour. Biol. Chem., 1917, xxxii, 245.

7. McCollum and Davis: Jour. Biol. Chem., 1915, xxiii, 231.

8. McCollum and Simmonds: 1917, xxxii, 181.

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