CLASSIFICATION OF FOOD ELEMENTS
By foodstuffs are meant the chemical elements appropriated by the
animal for the use of the body, as previously described.
By foods are meant those articles of diet found in the market which
contain the chemical elements used by the body in various combinations.
Bread, for example, contains all of the foodstuffs and has been called
the staff of life, because it sustains life. This refers to bread made
from the whole of the grain. White bread, as commonly eaten, is not the
“staff of life.”
Foods may contain elements, not foodstuffs, and not used by the body,
but cast out as waste. Certain foods, such as sugar, corn-starch, olive
oil, and egg albumin, contain only one foodstuff, as will be noted
in the following classification, in which the foodstuffs are grouped
according to the body uses.
The classification of foods is based on the principal organic
foodstuffs they contain. The preponderance of the elements in any one
food determines its chief use in the body.
It will be remembered that the chief uses of foods are to produce heat
and energy, to build the tissue of the growing child, and to repair
the tissues in the child and the adult.
Nearly all foods are made up of a combination of substances.
The following tabulations give the classification of foods based on
their predominating elements.
Nitrogenous foods:
Lean meat
Eggs
Gluten
Carbonaceous foods:
Sugars
Starches
Root and tuberous vegetables
Green vegetables
Fruits
Fats
Carbo-nitrogenous foods:
Cereals
Legumes
Nuts
Milk
Vegetables are mixtures of sugars and starches;
Fruits are mixtures of sugars, vegetable acids, and salts;
Milk, legumes, cereals, and nuts contain a more equal division
of sugars, fats, and proteins, and are therefore represented as
carbo-nitrogenous;
Lean meats, with the exception of shellfish, contain no starch, but all
meats contain protein, fat, and water.
{ Water { Corn-Starch
{ Inorganic { Salts Starches { Sago
{ { Tapioca
{
{ Carbonaceous { Glucose
{ (producing { Sugars { Cane Sugar
{ heat & energy) { { Syrups
{ { { Honey
Foodstuffs { {
{ { { Lard
{ Organic { Fats { Olive Oil
{ { { Butter
{ {
{ { { Egg Albumin
{ Nitrogenous { Proteins { Gluten
{ (for growth { Lean Meat
{ and repair)
In the above tabulation, examples are given of foodstuffs which are
almost pure representatives of their classes.
Corn-starch, sago, and tapioca are practically pure starch, containing
very little of any other element;
Glucose, cane sugar, syrups, and honey are almost pure sugar;
Butter, lard, and olive oil are nearly all pure fat;
Egg albumin, gluten of flour, and lean meat are almost pure protein.
As previously stated, however, no food contains but one element of
foodstuffs.
_NITROGENOUS FOODSTUFFS OR PROTEINS_
_Protein_ is a complex combination consisting of seventeen elements.
The digestive organs split up protein into these seventeen substances,
and they enter the blood thus split. When they reach the tissues, each
tissue selects the elements it needs and recombines them according to
its own peculiar functional uses.
Meat and eggs contain the complete protein.
Protein exists in all vegetables, but few vegetables contain protein
which is made up of the whole seventeen substances, hence more
vegetable food has to be eaten to secure the protein in the quantity
and combination necessary to maintain life.
Of these seventeen elements the predominating ones are nitrogen,
sulphur, and phosphates. The predominance of nitrogen has given the
proteins the name nitrogenous.
Proteins are the tissue builders.
In this connection it may be well to state that blood is a tissue; thus
meat and eggs build the blood, as well as muscle and sinew.
All nitrogenous foods contain considerable carbon—mostly in the form of
fat in the meat elements—but the carbonaceous foods contain so little
protein that the protein elements do not appreciably enter into the
nutrition.
Carbon and nitrogen in the carbo-nitrogenous foods are about equal in
proportion.
The nitrogenous or protein elements in the body constitute about
one-fifth of its weight. They form the basis of blood, lymph, muscle,
sinew, bone, skin, cartilage, and other tissues.
Worn-out body tissue is constantly being torn down and eliminated and
the protein in the foods must daily furnish material for repair, as
well as for building new tissue.
A young animal’s first need is for growth, as it has not learned to
exercise sufficiently to use much latent energy. The first food it
receives is an animal product—milk to babes and other mammals—while
the young chicken or bird is nourished by the yolk of the egg contained
within it. Sufficient yolk substance remains within the chick when it
is hatched to sustain its life for the first day or two.
Nitrogenous foods are more concentrated and contain less waste; thus a
smaller bulk is required than of vegetables and fruits. According to
recent experiments, the average adult requires from two to four ounces
of nitrogenous foods a day, to repair the waste. Happily, when more is
consumed, the system has the power up to a certain limit (depending on
the physical condition and the daily activity), to eliminate an excess.
It is needless to say that if the daily waste is not replaced,
digestion and nutrition suffer. The system must have the two to four
ounces necessary to supply the nitrogen daily excreted, or the tissues
themselves will be consumed.
The proteins, of which meat is the principal member, are classified as:
Albuminoids: albumin (white of eggs), casein (curd of milk), myosin
(the basis of lean meat and gluten of wheat);
Gelatinoids: (connective tissue of meat);
Extractives: (appetizing and flavoring elements).
If protein material is taken into the body in excess of its needs the
excess is used as fuel. While vastly more expensive, an excess of
protein is worth no more as fuel than starch is; 1 gram of protein
produces 4.1 calories of heat, no more than 1 gram of starch.
The proteins produce heat and energy when the supply of sugars,
starches, and fats is exhausted, but proteins alone form muscle and
the larger part of blood and sinew. They are, in this sense, the most
important of foods; they are also the most costly.
An excess of protein, usually eaten in the daily intake of food, then,
is of no practical use and can be eliminated with great benefit to the
pocketbook. Meat once a day is sufficient. The excessive consumption of
meat can be lessened with no lack of nutrition to the body. The trouble
is that meat is the first thing thought of for a meal; it is easily
prepared and housewives are not willing to use the thought and effort
necessary to secure a balanced meal without it.
_CARBONACEOUS FOODSTUFFS_
The carbonaceous foods are those used by the body for heat and energy
and are so named because they contain a large proportion of carbon—the
heat-producing element.
It is the carbon in wood, which, uniting with oxygen, produces heat and
light.
The carbonaceous foods are all composed of carbon, hydrogen, and
oxygen, the difference between them being in the different proportions
in which these elements are combined.
They are divided into two classes, Carbohydrates and Fats.
* * * * *
[Sidenote: Carbohydrates]
The carbohydrates embrace the _sugars_ and _starches_ and include such
substance as the starches of vegetables and grains (notably corn, rice,
wheat, and the root vegetables), and the sugar of milk, of fruits,
vegetables, and the sap of trees. Their chief office is to create
energy.
The starches are converted into sugar, so they are together given the
one name of carbohydrate. The name means that carbon and hydrogen are
contained in them in such a proportion that when oxygen unites with
the hydrogen, water is produced and the carbon is liberated. In this
chemical process heat is produced. One gram of carbohydrate produces
4.1 calories of heat.
They are almost entirely absent from meat and eggs, the animal having
converted them into fats.
When the digestive organs are in a normal condition carbohydrates
are easily digested.[2] They do not play a large part in the growth
of the body tissues, but they are utilized by the body to spare the
consumption of the fat which is stored in the tissues as a reserve.
This explains their action in preserving but not producing fat.
When there is an excess of fat and the desire is to reduce, the
carbohydrates should be limited that the body may call on the reserve
fat for heat and energy.
Few realize that after the starches and fats have been consumed in heat
and energy the tissues are consumed.
The assimilation of the carbohydrates is almost complete, so that the
energy derived from them may be closely calculated.
_SUGAR_
There are many varieties of sugar. Those commonly used as foods are,
cane sugar (sucrose), fruit sugar (levulose), sugar of milk (lactose),
sugar of malt (maltose), sugar of grapes or corn (glucose), maple
sugar, honey, and saccharin—a coal-tar product. They are derived from
plants, from trees, and from tubers or other vegetables.
_Cane sugar_ (sucrose) is derived from the juice of the sugar cane and
from beets. One-third of the world’s supply of sugar is derived from
the sugar cane and two-thirds from beets. From two to ten per cent. of
sucrose may be obtained from the maple tree. It is also found in the
sugar pea.
All sugars are carbohydrates—carbon, hydrogen, and oxygen—the oxygen
and hydrogen being in the proportions which form water (two atoms of
hydrogen and one of oxygen).
_Brown sugar_ is granulated sugar in an early stage of refinement.
_Maple sugar_ is obtained by boiling down the sap of the maple tree.
It is often adulterated with other sugars or with glucose from
corn, because they are cheaper. This adulteration does not make it
unwholesome, but causes it to lose its distinct maple taste.
The nutritive value of sugar is said to be about ninety-five per cent.
_Glucose_ was formerly derived almost entirely from grapes. Later the
process was discovered by which the starch in corn was converted into
glucose. It is produced so much more cheaply from corn that this is now
the chief source of supply.
Glucose is also found in most of the fruits, in combination with other
sugars. It needs little change to be absorbed by the system and quickly
overloads the digestive apparatus if much of it is eaten.
It is pure, wholesome, and cheap, and for this reason it is often
combined with other sugars. It is not so sweet as cane sugar, though
just as nutritious. Many of the syrups on the market are made from it.
Candy is often made from glucose instead of from molasses or cane sugar.
Much candy, unless one is actively exercising, tends to produce
indigestion.
While glucose is wholesome, it ferments readily.
Before sugar can be used by the system, it is changed into the easily
absorbed form of the sugar in grapes, by a ferment in the small
intestine. Hence digested sugar in the body is called grape sugar.
_Milk sugar_ needs less chemical change than other sugars and is taken
almost at once into the circulation. It is contained in the natural
food for the infant.
The digested sugar (grape sugar) is further changed in the body into
glycogen. When an excess of sugar or starch is consumed, it is stored
within the body as glycogen, until required.
Sugar is perhaps a better food than starch, because less force is
required for its digestion and it is easily assimilated, being more
readily converted into dextrose than are starches.[3] Moreover it
furnishes the heat and energy needed by those having small power to
digest starch.
Sugar is soon oxidized, and, for this reason may be eaten by those who
need to use an extra amount of muscular strength, or to get strength
quickly. It yields heat and energy within thirty minutes after eating,
and in times of great exertion or exhausting labor, the rapidity with
which it is assimilated gives it advantage over starch. Because it is
so quickly converted into energy it is valuable for children at active
play.
Experiments with soldiers on forced marches, and in Arctic
explorations, have shown the value of sugar as a food, in enabling the
men to withstand hunger, thirst, and fatigue. Taken in excess, however,
particularly by those of sedentary habits, it clogs the system as does
any other excess of material, creating difficulties for the liver and
kidneys.
During muscular activity, four times as much sugar is consumed in the
body as is ordinarily used in the body processes.
Used in limited quantities, therefore, according to the muscular
or brain power exercised, sugar is one of the best foods for the
production of energy.
When much sugar is eaten the starches and fats in the food should be
lessened to avoid overloading the system.
When eaten in excess, sugar may temporarily appear in the urine
unaltered.
It might be inferred that, as all starch must be converted to sugar
before it can be used by the body, starches might be discarded and
replaced by sugars. A small quantity of sugar, however, soon surfeits
the appetite, and if the foods were confined to those having a surplus
of sugars, sufficient food would not be eaten to supply other needs
of the body. This lack of appetite occasioned by an excess of sugar
is due, partly, to the fact that the gastric juice is not secreted so
freely when there is much sugar in the stomach.
Because of the slower secretion of gastric juice and the surfeit of
the appetite occasioned by them, sweetened foods should not be used
at the beginning of a meal, and, while a moderate amount of sugar is
desirable, a surfeit will cause indigestion. This is particularly
liable when one eats sufficient starch and sugar at a meal and then
eats candy between meals.
Sugar is so readily oxidized and supplies heat and energy so promptly,
that the fats stored in the tissues are not called on until the latent
energy in the sugar is used. The power of sugar to fatten thus lies in
sparing the use of body fat; when starch and fat are used in addition
to sugar an excess of fat quickly results. Therefore, those who wish
to reduce in flesh should eat sparingly of sugar that the starches and
fats may be used to furnish energy, but sugar should be as freely used
as the system can handle it, by those who wish to build up in flesh.
Broadly speaking, about one-fourth of a pound of sugar, daily, in
connection with other foods, is well utilized by the system, the
quantity depending on whether one leads an active or a sedentary life.
The natural flavor of fruits and grains is very largely destroyed by
sugar, which is used too freely on many articles of diet. Sugar should
never be added to fruits while cooking, if intended for immediate
use, as the acids of the fruits neutralize a portion of the sugar.
More sugar is thus used than is needed after the cooking process is
completed.
The sweet taste in all fruits and vegetables is due to the presence of
sugar. Sweet potatoes, beets, carrots, parsnips, turnips, grapes, figs,
and dates are especially rich in sugar, and when these are furnished
with a meal, in any appreciable quantity, the starches should be
restricted—notably bread, Irish potatoes, and rice.
Those who do hard work in the open air, because of the increased
oxidation, can consume larger quantities of sugar in pie or other
pastry, which ordinarily would be difficult to digest. One who lives an
indoor life should refrain from an undue indulgence in such foods.
For one who is undernourished, sugar is a desirable food, if the starch
be diminished in proportion as the amount of sugar is increased; but
the tendency in sweetening foods is to take more starch also than
the system requires, since it is the carbohydrate foods which are
ordinarily sweetened—not the proteins.
On account of their latent heat and energy, sugars are more desirable
in cold weather than in warm. For this reason Nature supplies them more
abundantly in the root vegetables, eaten more freely in cold weather.
More puddings and heavier desserts may be eaten in cold weather.
The desire of the child for sweets is a natural one, because the child
uses much energy, and sugar supplies this energy with less tax of the
digestive system. When the child begins to eat more solid foods, if
sugar is used in abundance for sweetening, he is no longer attracted by
the mild sweetness of fresh milk, and it is well not to sweeten cereals
or other foods, also to limit other sweets, when the child turns
against milk, in order to restore the taste for this valuable food.
Many authorities state that a child, up to its third year, should not
be allowed to taste artificial sweets, in order that the appetite may
not be perverted from the natural sweets of milk.
Sugar is better supplied the child in a lump or in home-made molasses
candy, rather than in the sweetening of porridge, oatmeal, or bread and
milk, etc.
Molasses is readily absorbed and is mildly laxative, and when young
children are not allowed to eat too much, it assists in keeping the
bowels open.
Sweet fruits, fully ripened, contain much sugar and should be freely
given to the child.
[Sidenote: Starch]
Starch is one of the most important carbohydrates. It is formed from
the carbon dioxid and water in the air and in the soil by the chemical
action of the sun’s rays on the cells of living plants.
As stated, corn-starch, sago, tapioca, and arrowroot are practically
pure starch. Rice is almost pure starch.
Corn-starch is obtained from young maturing corn; tapioca comes from a
tropical plant, cassava; sago from the pith of the sago palm; arrowroot
from a plant of the same name, a native of the West Indies.
Starch lacks flavor and for this reason all starchy foods are seasoned
with salt. Salt increases the activity of the saliva and pancreatic
juices.
All starches must undergo much chemical change by action of the saliva
and the intestinal juices, before they can be used by the body.
The digestion is begun by the saliva in the mouth and is continued in
the stomach, by the saliva, until the gastric secretions begin to act.
Starch is not acted on by the gastric juice but passes unchanged into
the intestines, where it is converted, by the pancreatic juice, into
dextrin, maltose, and glucose. It is thus absorbed into the blood.
After the digested starch passes into the blood it is taken to the
liver and is there changed into glycogen and is stored in reserve.
When the system needs to produce energy it is first furnished by the
glycogen. When this is exhausted the fats and proteins are used.
The _starches_ and _sugars_ then are really the energy “reserves” of
the body, any excess over the daily needs being stored until required.
Starchy foods should not be given to any one in whom, from disease or
derangement, the starch-converting ferments, ptyalin in the saliva and
pancreatin in the pancreatic juice, are lacking.
Because the child has not developed the ferment in sufficient
quantities necessary for starch digestion, starchy food must not be
given to a child under twelve to eighteen months; at least not until he
has teeth and chews his food. Then he should be given starchy food in
the form of a crust or hard cracker which he chews thoroughly and mixes
with saliva.
Potatoes or bananas which the child does not masticate, should not be
given him under the age of two years.
[Sidenote: Fat]
Fat is the most concentrated form of fuel and is readily oxidized. It
has about twice the fuel value of carbohydrates. It is almost pure
carbon, hence less chemical work is required to convert it into fuel,
but more oxygen is needed.
The average fat person does not breathe deeply and does not take in
sufficient oxygen to cause a combustion of the fat and produce energy.
He is thus inclined to be lethargic.
A pound of fat has about three times as much fuel value as a pound of
wheat flour, which consists largely of starch.
Common examples of fat are butter, cream, the fat of meat and of
nuts, and the oil of grains and seeds—notably the cocoanut, olive, and
oatmeal.
Fat forms about twenty per cent. of the weight of the normal body.
The body cannot remain in health for long unless a proper amount of
fatty food is eaten. Muscular and nerve action, and the formation of
the digestive secretions are all dependent on the energy derived from
the combustion of fat. Its use in this way spares the tissues from
destruction in the chemical processes necessary to life.
Both carbohydrates and fats are composed of carbon, hydrogen, and
oxygen, the difference being that there is less oxygen in fat. One
pound of starch requires one and one fifth pounds of oxygen for perfect
combustion, while one pound of suet requires three pounds of oxygen.
One ounce of fat yields two and one-half times as much energy as an
ounce of sugar or starch.
Fats are not digested in the stomach. The connective tissue about
the fat is dissolved here, and the fat is passed on into the small
intestine, where it is acted on by the bile and the intestinal juices.
These first change the fat into an emulsion and then into the form of
soap and glycerin. In this saponified form, it is in condition to be
absorbed and carried to the tissues, where it is assimilated and used
in energy. The commercial production of soap from oil is similar to the
chemical change in the body of fat into soap.
The supply of fat stored in the body depends on the quantity consumed
with the food, on the quantity used up in heat and energy in muscular
or mental exercise. The quantity assimilated depends somewhat on the
condition of the nerves. If the nerves are weak, they do not strongly
direct digestion and assimilation and less fat is used in the digestive
and assimilative processes; thus, in case of weak nerves more fat is
often stored in the tissues. An excess of fat often indicates sluggish
nerve activity.
Manual laborers require more fat for energy than do people whose habits
are sedentary. School-children, or children who play hard, should have
sufficient fat and sugar.
* * * * *
_Butter and Cream._ The fat present in milk, depends of course, on the
quality of the milk. There is as much butter-fat in a glass of fresh
Jersey milk as in a glass of cream from the milk of some cows. The
cream from some Jersey cows is eighty per cent. butter-fat.
Skimmed milk contains very little fat. If milk is drunk by the adult,
as a means of storing up more fat within the body, the cream, if
assimilated, should be stirred into it.
_The Fat of Meat._ This should be thoroughly cooked. All meats in the
process of baking or frying should be covered, in order to retain the
moisture. The fat in well-roasted beef is nutritious, but _to make fat
easily digestible it should be well masticated so as to break up the
tissue fibers which surround it_.
While fried foods are difficult of digestion (see page 192) because the
surface albumin is coagulated and the hot fat forms a coating around
it, making it difficult for the digestive juices to reach the tissue,
the fat of bacon is more easily dissolved because of the delicacy
of the fibers surrounding the fat cells. If thinly sliced and fully
immersed in its own grease in the process of frying, bacon is an easily
digested fat. The process of smoking the bacon renders it easier of
digestion.
Cooked bone-marrow is an easily digested form of fat which is usually
relished by those to whom any other fat is repulsive. It is useful in
some forms of anemia, as it contains considerable iron.
Eels, salmon, and mackerel contain much fat.
The Eskimos extensively use both whale and seal oil as a food.
The yolks of eggs are also rich in fat.
_Cod-Liver Oil_, pressed from the liver of the codfish, is easily
absorbed and assimilated by some. The odor is not pleasant and a little
lemon juice, salt, baking soda, or any flavoring substance may be added
to make it palatable. The pure oil taken in this way is, perhaps,
preferable to the prepared emulsions.
_Olive Oil_ is derived from ripe olives. It is often used when
cod-liver oil is not well borne. Many take olive oil for the purpose
of rounding out the figure with fat. If the system will assimilate
fat, taken in quantities, the fat may be stored; but, as a rule, one
is underweight because of a failure to assimilate the regular diet
and overloading the digestive organs with fat will not cause a better
assimilation. If the lack of flesh is due to sluggish assimilation
exercise should always accompany a diet for the building of flesh.
Olive oil, in moderation, is a good food when much heat and energy
are required, but if one’s occupation is sedentary, much fat is not
necessary.
_Cotton-seed Oil_ is often substituted or mixed with the cheaper grades
of olive oil. It is wholesome, if fresh, but has not the pleasing
flavor of the olive.
_Nut Oils_ are good, but, with the exception of peanut butter, are
not often used. English walnuts, hickory nuts, pecans, cocoanuts, and
Brazil nuts contain much oil. Nut oils are not well borne by some,
hence nuts must be sparingly used by them. If taken they should be used
with salt, and be thoroughly masticated.
Almond oil and olive oil are used in cooking, to some extent.
* * * * *
To summarize—digested sugar is called dextrose or glucose; digested
starch becomes first dextrin, then maltose (animal sugar); digested
protein is peptone; and digested fat is saponified fat.
_WATER_
No food element is more important for the needs of the body than water.
It is composed of oxygen and hydrogen. It forms the large part of the
blood and lymph.
The body will subsist for weeks on the food stored in its tissues; it
will even consume the tissues themselves, but it would soon burn itself
up without water, and the thirst after a few days without it almost
drives one insane.
Though it produces force only indirectly, it is entitled to be classed
as a food, because it composes about two-thirds of the weight of the
body and a large part of all the tissues and secretions. Yeo estimates
that the supply of water to the body should be averaged at half an
ounce for each pound of body weight.
It has been estimated that from four to five pints of water are
excreted each day by the body and therefore a similar amount should be
consumed daily. The average individual at normal exercise, requires
about seventy one and one half ounces of water daily, which equals
about nine glasses (one glass of water weighs one-half pound). Some of
this may be obtained from the food.
By reference to Tables I to V it will be noted that water forms a large
percentage of all food, particularly of green vegetables and fruits.
In order that the body may do efficient work in digestion and in the
distribution of the nutrient elements of the foods, and that the
evaporation from the body may be maintained, the water in the foods,
together with the beverages drunk, should consist of about seventy-five
per cent. liquid to twenty-five per cent. nutrient elements, or about
three times as much in weight as proteins, fats, and carbohydrates
combined.
Much of the water taken passes through the system without chemical
change and is constantly being thrown off by the skin, lungs, kidneys,
and intestines.
Some of the water is split up into hydrogen and oxygen to unite with
other substances in the chemical changes carried on during the process
of digestion, and some water is obtained from the food by the union of
hydrogen and oxygen liberated by the action of the digestive juices.
Few people give much thought to its resupply; yet, ignorant of
the cause, they suffer from its loss, in imperfect digestion and
assimilation, and in kidney and intestinal difficulties. If it is
withheld from the diet for a while, marked changes occur in the
structure and processes of the body. The effect is seen in the
lessening of the secretions, the increasing dryness of all the
tissues, including the nerves, and if the lack is long continued, in
progressive emaciation, weakness, and death.
Water is the heat regulator of the body, and the more energy used,
either in work or in play which results in more heat and evaporation,
the more water is required. An animal, if warm, immediately seeks water.
It is constantly being used in the body to form solutions in which the
waste products are held so that the eliminative organs may dispose of
them.
It is the chief agent in increasing the peristaltic action of both
the stomach and intestines, thus aiding in mixing the food with the
digestive juices and assisting the movement along the alimentary canal.
It increases the flow of saliva and of the digestive juices and aids
these juices in reaching every particle of food.
It dissolves the foods, and helps in the distribution of food materials
throughout the body, carrying them in the blood and the lymph from the
digestive organs to the tissues, where they are assimilated.
The blood carries the water to the various secreting and excreting
glands and its increased pressure aids both the secreting and excreting
activity. The digestive organs secrete their juices more freely,
digestion is aided, more nutriment is rendered absorbable, more carbon
dioxid is liberated, and more oxygen is taken into the blood which
thereby is made richer and more life-giving.
One engrossed in business or household cares may forget to take water
between meals. In such a case, the blood, in order to preserve its
volume, must draw the water from the tissues, which, in consequence,
become less moist. The mouth becomes dry, saliva is scanty, appetite
fails, the digestion is not so active, the digestive and other
secretions are lessened in quantity, the food in process of digestion
becomes more solid, its absorption in the intestine is more difficult,
it moves slowly along the intestinal canal, and constipation results.
The body is not so well nourished and falls a more ready prey to
disease.
The supply of fluid furnished to the kidneys is not sufficient,
the urine becomes more concentrated and irritation may result. The
foundation is thus laid for derangements of the kidney function.
_To maintain the equilibrium of the body forces, water drinking should
be established as a permanent habit and be firmly adhered to as a part
of the daily program._
Many claim that one’s thirst, as in the desire for food, is the only
safe guide to the amount and time of drinking, but these desires are
largely matters of habit, and tastes are often perverted. Unless the
condition is abnormal or the mind becomes so intensely active that one
fails to listen to the call of Nature, _the system calls for what it
has been in the habit of receiving_ and at the stated times it has been
in the habit of receiving it. It does not always call for what is good
for it.
Plants thrive after a shower because the falling water brings down
the impurities in the air which constitute plant food. Rain-water for
household use, therefore, should never be collected during the early
part of a shower or rain storm.
Spring water, from its filtration through earth rich in mineral
deposits, usually contains a certain percentage of those minerals, as
salt, sulphur, or iron, dissolved through the action of the carbon
dioxid contained in the water. Some of these springs have become
famous health resorts. The contained carbon dioxid gives spring water
its pleasant, sparkling taste. Spring water is remarkably free from
organic life.
Water as used in cities usually needs careful filtration and
purification to rid it of its contained sand and other impurities. The
housewife whose water supply is derived from rivers does this on a
small scale when she strains out the mud and sand from the water which
she is often compelled to use when the river is in flood and full of
impurities.
Drinking water should be perfectly clear and without odor. Even a small
amount of decomposing vegetable or animal matter can be detected by its
odor, if the water is confined for a short time in a bottle or closed
jar.
The health of the body depends to a large degree on the purity of the
water. Contaminated water is a menace to health.
Water which appears perfectly clear may be badly contaminated with
typhoid or other germs. For this reason no water should be used until
it has been boiled if one is not sure of its purity. Water from wells
near barns and cesspools is often impure.
“Hard” water, as derived from wells, is usually rich in calcium and
magnesium. When water contains a large percentage of these substances,
it usually causes constipation and indigestion and may aid in the
formation of gall-stones or gravel.
The kidneys are especially the great eliminators of water and aid in
maintaining the equilibrium of the blood. Except in conditions in which
they need rest, water should be freely drunk in order to stimulate them
to activity and to assist them in throwing off the body waste held in
solution.
One cannot form a better habit than that of drinking two or three
glasses of water on first arising and then exercising the stomach and
intestines by a series of movements which alternately contract and
relax the walls of those organs, causing their thorough cleansing.
This internal bath is as necessary as the cleansing of the skin. Often,
in gastritis or a catarrhal condition of the stomach, a large amount of
mucus will collect in the stomach over night, and the cleansing of the
mucous lining of the digestive tract is then most important.
If in good health, two or three glasses of cool water, vigorous
exercises for the vital organs, and deep breathing of pure air,
followed by a cold bath, will do more to keep the health, vigor, clear
skin, and sparkling eye than fortunes spent on seeking new climates,
mineral waters, or tonics.
When cool water in the morning seems to chill one, a glass of hot water
may be followed by a glass of cool.
The free drinking of water aids the activity of the skin, keeping the
tissues moist and the glands active.
Effervescing waters are usually drunk for their cooling and refreshing
effect. They should not be drunk to excess as they are usually combined
with syrups or sugar and will thus occasion derangement of digestion,
flatulence, and in some cases palpitation from the excess of gas which
presses on the diaphragm and impedes the action of the heart.
Mineral waters are drunk for the action of the salts which they contain
and are used for their laxative or their medicinal effect. Kissengen,
Hunyadi Janos, Epsom, Carlsbad, and our own Saratoga are examples of
laxative waters. These all contain sodium and magnesium sulphates and
are known as “bitter” waters.
Table waters, as Apollinaris, Vichy, or others containing carbon dioxid
are refreshing and wholesome and may be used in nausea and vomiting for
their quieting effect. Those who are unable to take milk will often
find its digestion will be aided if the milk be mixed with Vichy or
seltzer water.
When water is used as a hot drink it should be freshly drawn, brought
to a boil, and used at once. This sterilizes it and develops a better
flavor.
Cold water should be thoroughly cooled, but not iced. Water is best
cooled by placing the receptacle on ice rather than by putting ice in
the water. Impure or contaminated ice will contaminate water.
The theory has long been held that water drinking at meals is
injurious, the objection being that the food is not so thoroughly
masticated if washed down with water, and that it dilutes the digestive
juices. But this theory is now rejected by the best authorities.
_When water drinking at meals is allowed to interfere with mastication
and is used to wash down the food, the objection is well taken_, but
one need rarely drink while food is in the mouth; the water should be
taken at rest periods between mouthfuls.
_Thorough mastication and a consequent free mixing of the food with
saliva is one of the most essential steps in digestion_, and the flow
of gastric juice, as the flow of saliva, is stimulated by the water.
It is singular that the use of water at meals has long been considered
unwise when the free use of milk, which is about seven-eighths water,
has been recommended.
The copious drinking of cool water from a half hour to an hour before
a meal will cleanse the stomach and incite the flow of saliva and
gastric juice, thus aiding digestion.
Moreover, the digestive cells secrete their juices more freely and the
sucking villi absorb more readily when the stomach and intestines are
moderately full, either of food or water, and to fill the stomach with
food requires too much digestive and eliminative activity.
Water taken before meals passes through the stomach before the food,
washes away any mucus that may have collected over the mouths of the
gastric glands, stimulates them to activity, and prepares the stomach
to receive the food.
Results obtained, in building up about twenty thousand thin women, show
that the free drinking of liquid at meals has a tendency to increase
flesh. Probably one reason for this is the cleanliness and greater
freedom it gives to the absorbing and secreting cells of the mucous
lining of the digestive tract, the stronger peristalsis it occasions,
and the consequent better digestion.
When one wishes to reduce in flesh, water drinking at meals is
restricted.
If the contents of the stomach have become too concentrated or solid,
the water will render it more liquid, hence will aid the admixture with
the gastric juices and will enable it more readily to pass the pyloric
orifice.
Drinking at meals, therefore, has many more arguments in its favor than
against it.
All who have a tendency to the deposit of uric acid in the tissues, as
in gout, should drink freely of water to lessen the deposit of salts
from the blood which must maintain its proportion of fluid.
More water should be drunk if the meal consists largely of protein. The
nitrogen it contains is eliminated in a short time by the kidneys, the
amount of urine is increased, and more water must be drunk to make up
the loss.
In sickness, as in fever, the increased respiration causes a
corresponding loss of water from the skin and the lungs. If the bowels
are active as in diarrhea, much water is lost in this way. The increase
in the heat of the body also tends to dry all the secretions, hence
water must be taken to keep them in proper fluidity.
The patient is often too ill to ask for water or will forget to ask
for it. Constipation may result from this cause. It must be a part of
the nurse’s duty to see that a sufficient amount is taken. An excess
of cold water, if hastily taken, may cause cramps. If slowly sipped it
will do no harm.
Water may be given in fever in the form of lemonade; a small pinch of
soda will make it effervescent and more refreshing.
_There is no tonic like water, exercise, and fresh air._ The safe
method is not to allow the habit of drinking water with regularity to
be broken, unless for some necessary purpose, and then the habit should
be reinstated as soon as possible.
Soft water, that is, water containing no lime or other mineral, is
best. Hard water which causes any degree of curdling of soap, or a lime
crust in the bottom of a teakettle, renders digestion difficult.
Bacteria are killed and much of the mineral matter is deposited by
boiling the water. Boiled water tastes flat or insipid. It may regain
its original, fresh taste by filling a jar half full of water, and
shaking the jar so that the air passes through the water.
_SALTS_
The salts of sodium, potassium, magnesium, calcium and some other
substances, are necessary for proper bodily functioning. Taken with the
food, they pass into the tissues without change and can be recovered,
unchanged, from the tissues and the urine.
The uses of some of these substances are not thoroughly understood, but
if deprived of them, the nutrition of the body suffers.
Lime (calcium) is necessary for the bones and teeth and to preserve the
coagulability of the blood.
Sodium chlorid (common salt) aids the formation of hydrochloric acid
and the activity of the pancreatic juice.
The salts of iron are necessary for the blood.
Other salts are also needed to carry on the chemical reactions in the
digestive system.
Cereals, all vegetables, fruits, and nuts furnish both calcium salts
and sodium, potassium, and magnesium, which are the salts in the blood
and lymph. Minerals are also abundant in dried legumes (beans and peas).
Fruits and nuts contain the least amount of these salts, and meats,
vegetables, and cereals follow in the order named, cereals, that
is the whole of the grain—not the white flour—containing the most.
Any diet, therefore, which recommends the use of fruits and nuts to
the exclusion of other foods, depletes the system of some of the
body-building elements. The system may seem to thrive for a time on
such food because, perhaps, of the rest given to overworked organs,
but eventually the body lack will manifest itself; anemia may appear
or malnutrition become evident.
Milk furnishes salts in proper proportion for building the bones and
teeth of the baby; because of the lime which it contains it is a good
food for the growing child. After the child is one year old, eggs may
be added to the diet. During the first year the albumin and fats in the
egg are not well digested. It is especially essential that children
be furnished milk and eggs that they may be assured of the proper
proportion and quantity of calcium salts for growth.
Sodium chlorid (common salt) has been for ages recognized as an
important element in food, so important that in Eastern countries it is
the symbol of hospitality and friendship.
When taken in moderate quantities, salt increases the activity of the
gastric secretion and aids the appetite. When taken in excess, as many
who have formed the salt-eating habit do, it is an irritant to the
mucous membrane of the stomach and intestines and may interfere with
nutrition, causing dyspepsia, gastroenteritis or diarrhea from the
continued irritation.
The habit indulged by some of nibbling at salted nuts of various
kinds, at and between meals, may for a short time satisfy the needs
of the body for more salt than is usually taken with the food, but
such a habit persisted in will cause acidity of the stomach from
overstimulation of the hydrochloric acid producing glands; it will also
decrease the fluidity of the blood by causing the water to be drawn
from the blood for the use of the tissues. Irritative action is also
exerted on the kidney, as any excess of salt is excreted by this organ.
For this reason salt is often prohibited for those suffering from any
inflammation of the kidney, in Bright’s disease, etc.
When chemical tests show an excess of hydrochloric acid, salt should be
omitted from the diet.
A diet consisting largely of vegetables needs the addition of sodium
chlorid to supply sufficient salt for body uses; likewise more
salt than is contained in grass and fodder is needed for animals,
particularly for those producing milk. The scientific farmer salts his
cattle regularly, while wild animals travel miles and form beaten paths
to springs containing salt.
In rectal feeding, it is known that food absorbs more readily through
the large intestine if salted. It is probable that salt, in normal
proportions, also aids absorption in the stomach and small intestine.
_Potassium_ is next in importance to sodium as it constitutes the
chief salt in the muscles. It also aids the action of the digestive
secretions and the maintenance of the reaction of the urine. Potatoes
and apples are valuable foods on account of the potassium they contain.
_Calcium_, if in excess, may cause the formation of calculi, renal or
biliary. It is also found in the tartar which accumulates on the teeth,
in the hardening walls of the arteries in arteriosclerosis, etc. All
of the cabbage family are rich in calcium. Many mineral waters and the
water from many wells contain it in excess.
Those addicted to gall-stones, gravel, etc., should particularly avoid
“hard” water.
_Phosphorus_ and sulphur are obtained by the body from eggs and milk
and from such vegetables as corn, cauliflower, asparagus, and turnips.
_Iron_ is necessary in forming the pigment of the red blood corpuscles.
If, through some disturbance in digestion, absorption or assimilation,
the iron taken in the food is not utilized, or is insufficient in
amount, the blood-making organs do not receive the necessary amount
of this substance and the red corpuscles are not formed in sufficient
numbers. The blood becomes poor in hemoglobin, and the individual
becomes pale and loses vitality. This condition is known as anemia.
FOOTNOTES:
[2] For the process of digestion and the action of the digestive juices
on the various food elements, see _Let’s Be Healthy_, by Susanna
Cocroft.
[3] PUBLISHER’S NOTE: The conversion in the body of starch and sugar
into grape sugar, then into dextrose, then into glycogen, the glycogen
being again broken up into grape sugar, is fully explained in Susanna
Cocroft’s book _Let’s Be Healthy_.