form of neutral fat droplets, probably during the passage
through the walls, since they appear in this form in tJie
cells. They pass into the thoracic duct and thence into tJie
blood stream.

Absorption of Carbohydrates. — The carbohydrates are
chiefly absorbed in the form of monosaccharids. This has
been proved by introducing cane sugar or lactose into the
blood vessels and getting the greater portion of it back un-
changed by way of the urine. As the monosaccharids are
taken up by the capillaries lining the walls of the small
intestines, they are passed on to the portal vein and carried
by the portal blood into the liver, where they are stored
temporarily as glycogen, and given out to the blood in the
form of glucose as needed. After a meal rich in carbohy-
drates, the portal blood will be rich in glucose, while the
blood in general circulation contains about the same amount
as usual, about 0.1%.

Absorption of Proteins. — The absorption of the prod-
ucts of protein digestion occurs through the capillary blood
vessels and passes on to the portal vein. The metabolism of
protein is more complex tlian that of any of the food-
stuffs. It is probable that each living cell contains enzymes
which are capable of breaking down tJie body proteins with
the production of amino acids just as the proteins of the
food are broken down by enzymes of digestion, and accord-
ing to Sherman "it is not improbable that protein synthesis
also may be brought about by every living cell."

The Absorption of Water. — This does not occur in



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178 DIETETICS FOR NURSES

the stomach, as was formerly believed, but in the small
intestines.

The Absorption of the Mineral Salts. — This occurs in
conjunction with the other food material. Some of the min-
eral salts are much more soluble than others and are more
readily absorbed. The function of the mineral salts in the
body has already been described, and since they form a part
of every tissue and fluid in the body their absorption and
fate in metabolism must be studied with that of the other
chemical combinations.

ABSORPTION IN THE LARGE INTESTINES

The digestion of the food as it is passed into the last
portion of the alimentary canal has been largely completed.
However, that part which has escaped digestion in the
small intestine is finished and absorbed here. The impor-
tant peristaltic waves occurring in this region are anti-
peristaltic in character and have the property of churning
the food thoroughly and bringing a larger portion of it in
contact with the absorbing walls. The water which is left
in the food mass together with the products of the digestion
of the foodstuffs is absorbed in tiie first part of the large
intestine, leaving the remainder more solid. This residue
is known as feces or fecal matter.

The diagram on page 179 shows tiie various processes
through which the foodstuffs pass after absorption.®

Bacterial Action in the Alimentary Canal. — The
changes in the foods so far mentioned have been chiefly the
result of the activity of the enzjnnes existing in the various
digestive processes throughout the body. But there are
other changes which occur in the foods during their sojourn
in the digestive tract which are not accountable to enzymic

'This scheme applies to the protein, fat and carbohydrates with quanti-
tative variations only. Courtesy of Dr. A. R. Taylor, Leland Stanford
University.



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THE HUMAN BODY

Cells and Tissues



179



-f/'

^^^



Foodstuff





End Products



Combustion

action, but which, in fact, modify to a certain degree the
changes wrought by the enzymes. These are the result of
the activity of certain specific bacteria which inhabit the
entire digestive tract of the individual from a few hours
after birth until death. Some of these have so adapted
themselves to the existing conditions that, unless present
in overwhelming numbers, they are not only hawnless, but
they actually assist in protecting the organism from the
inroads of more harmful species. Many experiments have
been made to find whether or not bacteria are essential to
human nutrition, and the results of these experiments prove
that they are not. However, since they are so firmly estab-
lished in the body it is well to study the various types and
learn as much as possible of the products of their activity
and the influence which they exert in human nutrition.

Types of Bacteria. — It would be impossible and unnec-
essary to consider the action of all of the bacteria in the
body in this text, but it is necessary to consider those which
are prominent in bringing about decomposition of the foods
in the digestive tract. Sherman holds that there are three
main types having this property: "(1) the bacteria of fer-
mentation, such, for example, as the lactic acid bacteria;
(2) the putrefactive bacteria, such as the anaerobic B.
aerogenes capsulatus; (3) bacteria of the B. coli type, show-



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180 DIETETICS FOR NURSES

ing the character of both the fermentative and putrefactive
organisms but tending in general to antagonize the putrefac-
tive anaerobes." ^

Fermentation in the Stomach. — In the stomach, fer-
mentation of the carbohydrates with the production of
organic acids, and at times alcohol, occurs. The types of
fermentation taking place in the stomach are alcoholic,
lactic, butyric, acetic, formic, oxalic, and cellulose. The
bacteria inhabiting the gastric organs are dependent upon
air for existence, while those in the intestines are not.

Factors Influencing Excessive Fermentation. — The
factors influencing excessive fermentation in the stomach
are lack of "tone" and motility in the organ, insufficient
amount or absence of free hydrochloric acid in the gastric
secretion, dilatation of the stomach, and an excess of carbo-
hydrate foods in the diet. Of the latter, sucrose and glucose
are especially susceptible to the action of fermentative bac-
teria. Under normal conditions, that is, in health, the con-
ditions prevailing in the stomach are very unfavorable to
the development of bacteria of the putrefactive t3rpe, the
gastric juice exhibiting decided germicidal properties.
Then, too, the presence of air acts against their develop-
ment. Much of the so-called gastric fermentation does not
occur in the stomach but rather in the duodenum.

Bacterial Action in the Intestines. — In the lower part
of the small and in the large intestines, the bacteria of the
anaerobic type increase, conditions more favorable to their
development existing there than farther up in the intes-
tinal tract. However, there are a great many bacteria in
the whole of the small intestine. Those producing decom-
position of the unabsorbed proteins are especially promi-
nent in the colon.

Herter® states that "the presence in the colon of

* "Chemistry of Food and Nutrition," by Sherman.
•Herter's "Bacterial Infections of the Digestive Tract" (1907).



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THE HUMAN BODY 181

immense numbers of obligate micro-organisms of the B.
coli type may be an important defense of the organism in
the sense that they hinder the development of that putre-
factive decomposition which, if prolonged, is so injurious
to the organism as a whole. We have in this adaptation the
most rational explanation of the meaning of the myriads
of colon bacilli that inhabit the large intestine. This view
is not inconsistent with the conception that under some con-
ditions the colon bacilli multiply to such an extent as to
prove harmful through the part they take in promoting fer-
mentation and putrefaction."

E£Fect of Bacterial Activity in the Body. — In sum-
marizing the effects of bacterial action in the body it is
found that with the exception of oxalic acid, which is ex-
ceedingly injurious, and which, according to Herter, results
from the eating of large quantities of meat and sugar, the
products of fermentation are simply irritating in character,
while those resulting from putrefaction are distinctly toxic.
Among the substances deserving mention under this head
we have indol, skatol, cresol, and phenol. These sub-
stances are very soluble and upon absorption combine with
the sulphuric acid formed in the body and are excreted by
way of the kidneys where they appear in the urine as "con-
jugated sulphates," the chief of which is indican. The
amount of indican in the urine is taken as a measure of the
intensity of the putrefaction taking place in the body.

Metabolism. — Under the term metabolism we under-
stand the series of processes through the foodstuffs and
carried (a) in the conservation of the tissues of the body
and (6) in the maintenance of body temperature and phys-
ical work (Taylor). The processes concerned in metabo-
lism are chiefly those of building up, "anabolism," and
breaking down, "catabolism." In the processes of anabolism
the products absorbed are built into the tissues and cells of
the body. In catabolism, the worn particles from the cells,



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182 DIETETICS FOR NURSES

and the dead cells no long^ useful are broken up and
thrown out of the body. According to Taylor, "side by side
with these processes are the reactions of combustion,
whereby the temperature necessary for the life of the cells
is maintained, and the energy needed for external work
furnished."

Behavior of Carbohydrates in Metabolism. — As Sher-
man • has said: "At least two kinds of enzymes are believed
to be involved in the combustion of glucose in the tissue
cells, (1) cleavage enz3anes, which split the molecule into
fragments more easily oxidized, and (2) oxidizing enzymes
or oxidases which stimulate the oxidation of the cleavage
products. Both kinds of enzymes are widely distributed
through the body and are believed to be normal constitu-
ents of all active cells."

Production of Energy. — It has been proved that the
energy for external and internal work is produced largely
from the glucose brought by the blood and oxidized in the
muscles.

When a surplus amount of carbohydrate food is eaten,
over and above the immediate needs of the body for fuel,
it is stored in the liver and muscles as glycogen, which can
be readily reconverted into glucose. When the supply of
carbohydrate food is greatly in excess of the body's needs,
that is when the liver and muscles cease to store glycogen,
it is built up into adipose tissue and furnishes a readily
available source of emergency fuel.

Fate of the Carbohydrates. — After their oxidation the
end products of carbohydrates, that is, the substances which
are no longer available for use in the body, leave it in the
form of carbon dioxide and water by way of the kidneys
(urine), the skin, the lungs, and the intestines.

Fate of the Fats. — The fats upon absorption are taken

•"Chemistry of Food and Nutrition," by Sherman.



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THE HUMAN BODY 183

up by the lymph vessels instead of the capillaries and enter
the blood with the Ijnuph. According to various investi-
gators, the fat which causes the turbidity of the blood
plasma at the height of absorption will, as a rule, disappear
after a few hours, part of it being burned as fuel, producing
energy for the internal and external work of the body, and
at least a part of the fats eaten being rebuilt into body fat.
The end-products of fat metabolism, like those of the carbo-
hydrates, consist of carbon dioxide and water, and leave the
body by the same excretory channels.

When the normal oxidation of the fatty acids is inter-
fered with or is overtaxed, a different reaction from that
which usually occurs may take place, and this results in
an excretion of acetone in the urine (see Chapter on Dia-
betes).

Protein metabolism is certainly more complex than that
of either of the other active organic food groups. The
amino acids which are the products of protein digestion are
taken up by the capillary blood vessels in the intestinal
walls and are passed by them into the portal vein, soon to
become available for the needs of the body.

Fate of the Proteins. — After utilization in the body,
the proteins, like the other foods, leave certain waste prod-
ucts which indicate to a greater or lesser extent tiie com-
pleteness with which the organism has made use of the food
materials. The end-products of protein metabolism are:
urea, ammoniiun salts, purin bodies, and creatinin. These
products leave the body chiefly in the urine. The chief end-
product in man is urea. This substance represents from
82-88% of the total nitrogen excreted by the kidneys.
However, the less highly oxidized products represent the
incomplete products of protein metabolism and thus indi-
cate the changes through which these products must pass
before being changed into urea. If for any reason there is



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184 DIETETICS FOR NURSES

an impairment of the liver through which they must pass
and where the change into urea is accomplished, there will
be a rise of ammonia and a corresponding decrease in the
output of urea in the urine. Thus, ammonia is formed at
the expense of the urea. This occurs in fevers, diabetes, and
certain structural diseases of the liver. According to Sher-
man: ^^ "Normally about 2 to 6% of the total nitrogen
eliminated is in the form of ammonium salts, the amount
depending largely upon the relation between the acid-
forming and base-forming elements in the food."

Acid-forming and Base-forming Foods. — MendeP^
states: "There are foods which act as potential acids and
others which function as bases in the organism. When
burned up either in the laboratory or in the body cells, they
have a preponderance of acid or base, as the case may be,
in their ash. In this respect potatoes, apples^ raisins, and
cantaloupes, for example, are base-forming foods which
depress the output of ammonia and increase the solubility
of uric acid in the urine, whereas meal, cereals, and prunes
(the latter with their content of benzoic acid) furnish acids
in predominance.

Purin Bases. — These compounds are formed in the
body as cleavage products of nucleoproteins or taken into
the body in food. The chief of these products are adenin,
guanin, hypoxanthin, xanthin, and uric acid. The latter
is the most highly oxidized of all the purin bases and is the
form in which they are chiefly eliminated in the urine.

Formation of Uric Acid. — The formation of uric acid
can in a measure be controlled by attention to the diet,
eliminating those foods known to be purin bearing. Nor-
mally from 1 to 3% of the nitrogen eliminated will be
in the form of uric acid. The normal human being

*• "Chemistry of Food and Nutrition," by Sherman.

" "Npwer Points of View Regarding the Part Played by Different Food-
Btuflfs in Nutrition," by Lafayette Mendel, Ph.D. Read at the Sixty-fifth
Annual Meeting of the American Medical Association, June, 1914.



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THE HUMAN BODY 186'

oxidizes about half of the purins eaten and excretes about
half, mainly in the form of uric acid. According to Mendel,
the formation of uric acid takes place throughout the body,
and its partial destruction is accomplished by the kidneys,
muscles, and liver. The formation of purins in the body
and their elimination in the form of uric acid is especially
significant in certain pathological conditions, gout, for
example, in which the body has difficulty in eliminating
these compounds.

The purin bodies are both endogenous and ^cogenous —
that is, they may be brought into the body in food as such,
or they may be formed as a result of the metabolism of the
body tissues. For this reason the damage wrought by these
substances may to a certain extent be controlled by eliminat-
ing the purin-bearing foods from the diet. Mesh-foods are
high in purins, especially the highly nucleated glandular
organs, liver, th3anus (sweetbreads), etc., kidney, beef, mut-
ton, veal, pork, chicken, turkey, goose, sardines, anchovies,
all kinds of fish except cod. Among the vegetable foods
asparagus, beans, peas, and spinach are highest in purins.
Boiling extracts much of the purins from food. Meat espe-
cially should be prepared by this method, if used in the
diet of individuals suffering from gout. Eggs and milk are
purin free, and may be used freely. Certain substances in-
crease the difficulty of eliminating uric acid. Alcoholic
beverages for example are especially deleterious.

Creatinin. — This end-product of protein metabolism is,
like uric acid, endogenous and exogenous. It is one of the
normal constituents of the urine. The quantity is fairly
constant for the individual, averaging about 0.02 gram per
kilogram of body weight per day.

Mineral Metabolism. — A study of the organic food-
stuffs reveals the fact that many of the mineral salts con-
cerned in nutrition enter the body in organic combination
with tiiose constituents. Certain of the mineral salts, how-



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186 DIETETICS FOR NURSES

ever, enter, exist in and leave the body in the same organic
form in which they occur in the food materials. This is
true of chlorine, which for the most part, functions in and
leaves the body in the form of chlorides (chiefly sodium
chloride). A small part of the chlorine is used in the pro-
duction of the hydrochloric acid of the gastric juice.

Sulphur and iron, both enter the body as essential con-
stituents of proteins, and their metabolism occurs with
that of these foodstuffs; the sulphur being converted largely
into sulphuric acid must be neutralized at once, and it leaves
the body by way of the urine as inorganic sulphates. Part
of the sulphates are excreted as ethereal (conjugated)
sulphates; the amount excreted in this form depending
largely upon the extent of purification in the intestinal
tract."

Phosphorus. — This mineral salt is found to be present
as an essential constituent of certain proteins, fats and
carbohydrates. It also enters the body in the form of inor-
ganic phosphates. During the digestion and metabolism of
the organic foodstuffs the phosphoric acid radical is split off
and eventually nearly all of the phosphorus leaves the body
in inorganic form (inorganic phosphates).

Calciimi. — Being the chief constituent of the bones,
large quantities of calcium salts are stored in the skeleton
of the child both before and after birth. The functions of
calcium have already been discussed. That part not stored,
which has finished its work in the body is excreted through
the intestinal wall and leaves the body by way of the feces,
only a small part of the calcium concerned in metabolism
being excreted in the urine.

The Process of Osmosis in the Body, — The influence
exerted upon the process of osmosis in the body is one of
the most important parts played by the mineral salts in

"See "Bacterial Action in the Body," p. 181.



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THE HUMAN BODY 187

metabolism. The fact that these chemical substances are
indispensable to the metabolic processes makes it necessary
for the nurse to know where they can be found in food
and how best to use them.

Metabolism of Body Tissues. — The constant breaking
down and building up of the tissues of the body and the
evolution of heat as a by-product of the energy expended
may be summed up in the term "metabolism." The me-
tabolism of the body is normally supported by the food
ingested. However, it is a known fact that were no food
eaten the processes would continue just the same, the dif-
ference only being the use of the body structure instead of
food materials. According to Sherman, the chemical
changes and energy transformations are of course insep-
arable. It has become customary to speak of the metabo-
lism of matter and the metabolism of energy, and to regard
the extent of the metabolism of any material substance as
measured by the amount of its end products eliminated, and
the extent of the energy metabolism as measured by the
amount of heat or of heat and external muscular work which
the body gives off.

In summarizing the important factors in the utilization
of food by the body several distinct points are made evident:

1. The composition of the body, and the composition of
food, are practically the same.

2. Food must make good the losses resulting from me-
tabolic processes and physical activity.

3. Utilization of food by the body necessitates:

(o) Transformation through a series of processes:

(1) Digestion.

(2) Absorption.

(3) Metabolism.

(4) Elimination.



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188 DIETETICS FOR NURSES

(6) Factors influencing use of food:

(1) Stimulation of secretory cells through ap-
petite juice (stomach); hormone secretin
(intestines).

(2) Factors retarding use of food : — Fear,
worry, anger, nervous excitement, fatty
foods and alkaline carbonates (bacterial ac*
tion causing fermentation and putrefac-
tion).

PBOBLEMS

(a) Outline the processes through which a slice of bread
and butter must pass, from the time it is eaten until
it reaches the blood stream.

(b) Outline with a diagram the manner in which the food-
stuffs are utilized in the body.

(c) Show in the form of a table the effect of the enzymes
on proteins, on fats, on carbohydrates.



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SECTION IV
DIETO-THERAPY



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CHAPTER VIII
PREGNANCY AND LACTATION

There are many traditions in regard to the food require-
ments of the prospective mother. Many of these have been
proved fallacies. As a matter of fact it is the woman more
than the developing child who is likely to suffer if the diet
is insufficient or badly balanced.

Factors A£Fecting Diet during Pregnancy, — In formu-
lating a dietary for the pregnant woman, then, not only
must the needs of the child be considered but those of the
mother also, since the developing embryo draws from the
body of the woman materials necessary for its growth, and
if these needs are not covered by an increase in the diet,
her body and that of the child also will show evidences of
lack of nourishment.

Phosphorus and Calcium Requirements. — If, for ex-
ample, the mother's diet is lacking in those materials which
produce growth, or is deficient in those mineral salts, such
as those of phosphorus and calcium, which are requisite and
necessary for the growth of bones in the infant, the mother^s
bones and teeth will show this loss and in all probability
the baby will sooner or later also show a like deficiency.
However, it must be remembered that the pregnant woman
is under a strain, both physical and mental. She must not
be encouraged to eat beyond her needs or the digestion will
be disturbed.

Nutritional Disturbances in Early Months. — The nu-
tritional disturbance manifested by nausea and vomiting in
the morning is due, not to the stomach or any disturbance
therein, but to the fact that a mild form of poisoning

191



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192 DIETETICS FOR NURSES

occurs, resulting from the substances produced through the
formation of the placenta reaching the general circulation
on account of the incomplete establishment of the coimec-
tion between the embryo and the mother. As soon as this
connection is complete and fetal circulation is established
this "morning sickness" disappears.

Food Requirements of Prospective Mother. — The
food requirements of the prospective mother are not ma-
terially afifected during the first four months of gestation,
and even after this, when the infant is developing rapidly,
and up to the date of its birth, the mother's requirements
are only increased about 20%. The amount of food neces-
sary to cover the body needs, for maintenance and energy
of a woman living a sedentary or moderately active life,
plus 20% for building materials for the growing child, will
be adequate for the pregnant woman. Thus, if her needs
are ordinarily from 2,000 to 2,400 calories per day, after
the fourth month they will probably be increased to 2,400
or 2,800 calories a day and will rarely ever be more than
3,000 calories a day.

Dietetic Treatment of Normal Pregnancy. — The pe-
culiar conditions surrounding the woman at this particular
time must be taken into consideration in arranging her diet.
The building foods which are necessary for the developing
child must be given in the simplest form, milk and eggs
being used liberally and meat sparingly to obviate any
unnecessary tax being placed upon the kidneys. The use
of fruit and green vegetables to supplement the milk and
^gs is urged. It has been found advisable at such times