DIET AND NUTRITION
Most interesting is the study of the food as it passes through the
processes of digestion, absorption, assimilation, and oxidation--all
definite and important parts of the great cycle through which
everything we eat passes on its way from the table to the tissues.
Elimination is the last step in nutrition, and is the process by which
the body rids itself of the broken down cells and other poisonous and
useless wastes. These various phases of bodily nutrition may be
expressed in a single term--metabolism.
What we eat and how much we eat must be carefully planned, for our
body temple is really made of what we eat. If you were erecting a
beautiful mansion you would not think of allowing cheap, trashy, and
inferior building materials to enter into the construction of your
home. Neither should you permit unfit and inferior materials to become
a part of the daily dietary of your little boy or girl, thus to become
a part of their bodily structure.
ASSIMILATION OF FOOD
Following the process of digestion in the stomach and intestine, the
nutritive food elements are absorbed through the wall of the bowel by
the wonderfully adapted little villus, and distributed by various
routes to the uttermost parts of the body. The sugars (all starches
are changed into sugar) are carried in the portal blood stream to the
liver, where they are actually stored away in the form of glycogen
which, in a most intelligent manner, is dealt out to the body from
hour to hour as it is needed for fuel. If all the sugar, after a
hearty meal, were poured into the circulation at once, the blood
stream would be overwhelmed and the kidneys would be forced to
excrete it in the urine. This unnecessary waste is avoided by the
liver's storing sugar after each meal and dealing it out to the body
as required.
Likewise, the proteins also pass through the liver on their way to the
body. Just what action the liver exerts upon proteins is not wholly
known at the present writing. The digested fats are absorbed at once
by the lacteals, the beginning of the intestinal lymphatic system, by
which they are carried to the large veins at the root of the neck and
there emptied into the blood stream. We have now traced our various
food elements through the processes of digestion and absorption in the
alimentary tract, some going through the liver, and others through the
lymphatic system, until they circulate in the blood stream itself.
It is from these food substances, circulating in the blood stream,
that the various cells of the body must assimilate into themselves
such portions as they require for purposes of heat and energy and for
the repair of their cell substance. This specialized work of cell
assimilation converts the dissolved watery food in the blood into
solid tissues, exactly reversing the process of digestion.
With a most profound intelligence, each of these body cells and
tissues, bone and nerve fiber, muscle and organ, selects from the
blood stream just its supply or portion of the food elements requisite
to its upbuilding and maintenance. The mysteries of assimilation are
effected by means of chemical substances called "enzymes," similar to
those found in the digestive organs, but acting in an entirely
different manner, in that they build up solids out of liquids instead
of converting solids into liquids.
ELIMINATION OF BODY WASTES
Metabolism consists of a twofold rôle--an upbuilding and a tearing
down process. After the food is all digested, absorbed, and
assimilated, having become a part of the bodily organ, bone, muscle,
and nerve fiber, then begins the work of tearing it down--of
liberating its heat and energy--to be followed by its elimination
from the body through the sweat glands, uriniferous tubules of the
kidneys, etc. The carbohydrates (starches and sugars), together with
the fats, are completely burned up in the body and are then eliminated
in the form of water (thrown off through the sweat) and carbonic acid
gas given up by the lungs.
The proteins, or nitrogenous foods, are not so completely burned up in
the body. The ashes which result from their combustion are not simple
substances like the water and CO_{2} of the carbohydrates. This
protein ash is represented by a number of complicated substances, some
of which are solid (protein clinkers), which accumulate in the body
and help to bring about many diseases, such as gout, headache,
fatigue, biliousness, etc.
These protein ashes and clinkers are further acted upon--split up and
sifted--by the liver, and are finally eliminated by the kidneys in the
form of urea, uric acid, etc. The body being unable to store up
protein, is often greatly embarrassed when one eats more of this
substance than is daily required to replenish the waste of the body,
for it must all be immediately split up in the system, and the
over-abundant and irritating ashes must be carried off by the
eliminating organs. Now, the overeating of sugars, starches, or fats,
is not such a serious matter, as they may be stored in the liver and
subsequently used; and even if they are eaten in excess of what the
liver can care for they accumulate as fat or add extra fuel to the
fires of the body, their ashes being carried off in the form of such
harmless substances as water and carbon dioxide (CO_{2}); but the
overeating of protein substances is always a strain on the body and
should be avoided.
ELEMENTS OF NUTRITION
There are seven distinct elements entering into the composition of
human foods--protein, starch, sugar, fat, salts, cellulose, and water,
not to mention enzymes, vitamines, and other little-known chemical
principles. These elements are all variously concerned in the
nourishment, energizing, and warming of the body.
PROTEINS
The proteins are the structure builders of the body. While starches,
fats, and sugars may be compared to the coal that feeds the
locomotive, the proteins represent the iron and steel that are used
from time to time to repair the engine and replace its worn parts. The
essential chemical difference between starch and protein is that the
latter contains nitrogen and a small amount of sulphur and phosphorus.
The most common forms in which protein is used for food are the
glutens of the grains, the legumes, nuts, cheese, the white of egg,
and lean meat.
STARCHES
The starches are by far the most abundant of all elements in human
food. They enter largely into the composition of nearly all plants and
seeds. Under the influence of the sunlight, the green-colored plants
gather up the CO_{2} of the air and, with the water absorbed from the
ground, build up starch. The plant takes all the carbon from which
starch is made from the air, but while the atmosphere contains almost
eighty per cent of nitrogen, the plant is unable to use it; it must
secure its nitrogen from the decaying refuse of the soil. Thus the
plant utilizes the waste products found in air and earth in the
building of its food substances.
Starch exists in the form of small granules. Since each little starch
granule is surrounded by a woody envelope of cellulose, it becomes
necessary to cook all starches thoroughly in order to burst this
cellulose envelope and thus enable the saliva to begin, and other
secretions to continue, the work of digestion.
FRUIT SUGARS
The sugar of fruits represents a form of food requiring practically no
digestion; while the sugar found in beets, the cane plant, and the
maple tree, must be acted upon by the digestive juices of the
intestine before their absorption can take place. During the winter,
the maple tree stores its carbohydrates in its roots in the form of
starch. With the advent of spring Mother Nature begins the digestion
of this starch--actually turns it into sugar--and in the form of the
sweet sap it finds its way up into the tree trunk to be deposited in
the leaves and bark in the form of cellulose, a process very similar
to that performed by digestion in the human body, where starch by
digestion is first turned into sugar, and afterwards deposited in
another form in the liver and muscles.
Dextrine is a form of sugar resulting from thoroughly cooking or
partially digesting starch. There are about twenty-five stages or
forms of dextrine between raw starch and digested starch or fruit
sugar. Dextrine is found in the brown-colored portions of well-toasted
bread.
FATS
Fat is a combination of glycerine and certain fatty acids. As a food,
it is derived from both the animal and the vegetable kingdom. Animal
fat consists of lard, suet, fat meat, etc., while fat of animal origin
is represented by cream, butter, and the yolks of eggs. The vegetable
fats are found in nuts, especially the pecan, cocoanut, Brazil, and
pine nuts; also in the grains, particularly oats and corn. The peanut
also contains a considerable amount of fat. Of the fruits, the banana
and strawberry contain a trace of fat, while the olive is the only
fruit rich in fat.
As a food, fat is used in three forms. The emulsified form is
represented by cream, olive oil, and nuts. When the tiny globules of
fat, which are each surrounded by a little film of casein, are
crushed--united into a solid mass--we have a free fat. This form is
represented by butter and other animal fats. Another form is fried
fat--fat which has been chemically changed by heat with the
development of certain irritating acids.
MINERAL SALTS
The mineral elements comprise but a small part of human food as
regards weight, but they are extremely important to the health of the
child as well as the adult. As found in the food, they are not in the
form of mineral salts, like common table salt. The salts of food are
living salts, organic or organized salts, such as are found in the
growing plant. These salts are of great value to the various fluids
of the body, and also as stimulants to nerve action, but more
particularly in the work of building up the bones.
Salts are found largely in the cereals. A small amount is also found
in vegetables, particularly the potato, as well as in most fruits.
CELLULOSE
Cellulose represents the great bulk of all vegetables and fruits. It
is digested by most animals, but in man it is digested only to the
extent of about thirty per cent. The presence of a large amount of
cellulose in the food enables us often to satisfy the appetite without
injury from overeating. It serves to give bulk to the food, and
thereby possibly acts as a preventive to constipation.
WATER
Water fills an important place in the nutrition of the body. The food
changes in connection with digestion, assimilation, and elimination,
can take place only in the presence of water. Water constitutes from
fifteen to ninety-five per cent of the various foods. The watery
juices of vegetables and fruits consist largely of pure, distilled
water, in which fruit sugar is dissolved, with added flavoring
substances. Water is absolutely essential to the performance of every
vital function connected with human metabolism.
ANIMAL HEAT
The source of heat in the animal body was the subject of much
superstitious speculation on the part of ancient scientists. It is now
known that animal heat is derived from the food we eat by means of a
peculiar process of vital oxidation--effected in the presence of
oxygen--by the action of water and enzymes upon the food elements
absorbed by the living cell. This process of oxidation liberates the
heat and energy stored by the sun in the food, and thus the body is
kept warm by this constant combustion of the digested foodstuffs. The
starches and sugars, together with the fats, represent food elements
which serve as the body's fuel. By this means we are able to maintain
a constant body temperature of almost one hundred degrees.
The average human body produces enough heat every hour to raise two
and one-half pounds of water from the freezing point to the boiling
point. This is equivalent to boiling about seven gallons of ice-water
every twenty-four hours. Differently expressed, the body gives off
each hour the same amount of heat as a foot and a half of two-inch
steam coil. This is the same amount of heat which would be produced by
burning about two-thirds of a pound of coal.
FUEL VALUE OF FOODS
Expressed in terms of English weight, the fuel value of the three
different food elements would be:
1 ounce of carbohydrates 127.5 calories
1 ounce of proteins 127.5 "
1 ounce of fat 289.2 "
It will be observed that fat contains more than twice as much heat as
the carbohydrates. This is due to the fact that fat contains more
carbon than either starch or sugar. Next to fats, starches and sugars
are the most important fuel elements. Protein is a very extravagant
form of food for fuel purposes. Proteins are the most expensive
elements of human food; they are incompletely burned in the body, and
inasmuch as they leave behind distressing and disease-producing ashes,
it is clearly evident that only sufficient amount of proteins should
be eaten each day to supply the demand of the body for repairs. We
should depend more largely upon the carbohydrates and fats for heat
and energy.
A large part of our food is required to furnish heat to take the place
of that lost by radiation from the skin, and this is why children
require more food than adults--they have a larger skin surface in
proportion to their weight, and therefore lose more heat by radiation,
and it is for this reason that the food for the growing child must be
wisely and carefully selected.
DIET FOR CHILD TWO TO THREE YEARS OLD
_Breakfast_, 7-8 A. M.: Fruit; cooked or toasted cereal served with
thin cream; a soft boiled or coddled egg; bread (two or more days old)
and butter; plenty of milk.
_Dinner_, 12-1: Soups; creamed vegetables--tomato, corn, peas, and
celery; any two of potatoes--creamed, mashed, or baked--carrots,
beets, spinach, peas, cornlet, squash, cauliflower, asparagus tips,
string beans; protein dish--the puree of dried beans, peas, or
lentils; macaroni or carefully selected meats; dessert--apples, baked
or sauce--or other fruits, junket, custard, milk.
_Supper_, 5-6 P. M.: Fruit, bread (bran bread if constipated); milk;
porridge, with rich milk or milk toast; sweetened graham crackers.
FOODS ALLOWED CHILDREN OF FOUR YEARS AND OLDER
_Protein Dishes_: Purees of dried peas; lentils; beans; macaroni;
eggs--soft boiled, poached, scrambled, or omelette; meats--steak,
chops, chicken, turkey, broiled fish.
_Cereals_: All the toasted-flake foods; toasted and not too fresh
bread, including both graham and bran; hominy; corn meal; oatmeal;
farina; rice; barley; tapioca; sago, etc.
_Soups_: Creamed vegetable soups of all kinds and broths.
_Vegetables_: Potatoes; all the small green vegetables; lettuce;
stewed celery; beets; squash; cauliflower, etc.
_Fruits_: All, if stewed or baked. Raw fruits--pears, peaches, ripe
apples, berries, oranges, persimmons, grape-pulp without seeds, etc.
_Desserts_: Custard; jellos; junkets; home-made ice cream; sponge
cake; baked fruits with whipped cream, etc.
FOODS TO BE AVOIDED BY YOUNG CHILDREN
1. _Doughy breads_, griddle cakes, insides of muffins, hot biscuits,
etc.
2. _Fried meats_, such as sausage, oysters, pork, ham, veal, salt
fish, corned beef, dried beef, etc.
3. _Foods that are hot when they are cold_--such as catsup, horse
radish, mustard, highly spiced pickles, sauces, etc.
4. _Rich pastries_, puddings, unripe fruit, salted peanuts, and highly
concocted dishes.
5. _Certain salads_, containing coarse but easily swallowed foods,
with highly seasoned sauces.
6. _Tea, coffee, and all alcoholic beverages._
7. _Soft candies_, chocolate creams, bon-bons, patties, etc.
Average normal children crave sweets, and since their normal food is
about seven per cent sugar it is not to be wondered at. There are many
forms of pure, hard candies which may be taken by the three-year-old
child. They are stick candy, fruit tablets, sunshine candies, and
other varieties which may be sucked.
All soft candies, such as chocolate creams, bon-bons, patties, etc.,
are to be avoided. Hard candies, taken along with the desserts at meal
time, in no wise injure the normal stomach of the healthy child.
The other members of the family should set a correct example by
sucking the hard candies rather than chewing them; for if the hard
candies are allowed to dissolve slowly in the mouth they produce a
weak solution of sugar, which does not interfere with digestion as do
the strong and concentrated sugar solutions which result from chewing
chocolate creams, bon-bons, etc.
Candy, cookies, sandwiches, or bits of cake should never be allowed
between the meals.
EATING BETWEEN MEALS
Children who do not eat well at the breakfast table, if given a
"piece" at 10 A. M., will not be ready for the 12 o'clock meal; and
then another "piece" at 2 P. M. interferes with the normal appetite at
6 P. M. Digestion is disturbed, the nervous system irritated, and a
"puny child" is often the result.
Bring the three-or-four-year-old to a well-selected breakfast some
time between 7 and 8 A. M. Then nothing--absolutely nothing--but water
must pass the lips between that breakfast hour and the 12 o'clock
meal, which should be a good one. Then the interval until 5 or 6 P. M.
is passed in the same manner. At the evening meal the appetite is
again whetted: and a good appetite always means good gastric juice to
digest the meal. And so, good mother, guard carefully the interval
between meals if you would have good digestion and good health for the
little folks.
DAILY FOOD REQUIREMENT
The following table, taken from _The Science of Living_,[B] shows the
minimum of calories or food units required by boys from five to
fourteen years of age and girls from five to twelve:
BOYS
Skin Daily
Age Height in Weight in Surface in Calories or
Years Inches Pounds Sq. Ft. Food Units
5 41.57 41.09 7.9 816.2
6 43.75 45.17 8.3 855.9
7 45.74 49.07 8.8 912.4
8 47.76 53.92 9.4 981.1
9 49.69 59.23 9.9 1043.7
10 51.58 65.30 10.5 1117.5
11 53.33 70.18 11.0 1178.2
12 55.11 76.92 11.6 1254.8
13 57.21 84.85 12.4 1352.6
14 59.88 94.91 13.4 1471.3
GIRLS
Skin Daily
Age Height in Weight in Surface in Calories or
Years Inches Pounds Sq. Ft. Food Units
5 41.29 39.66 7.7 784.5
6 43.35 43.28 8.1 831.9
7 45.52 47.46 8.5 881.7
8 47.58 52.04 9.2 957.1
9 49.37 57.07 9.7 1018.5
10 51.34 62.35 10.2 1081.0
11 53.42 68.84 10.7 1148.5
12 55.88 78.31 11.8 1276.8
[B] Sadler, William S., _The Science of Living; or, The Art of Keeping
Well_. A. C. McClurg & Co.