To keep all of these various tissues and organs in health, as has been
suggested heretofore, we must be properly nourished by the most suitable
food. It is of prime importance, therefore, to know the true value of
foods in order that we may select wisely. To a higher degree than is
commonly realized, our physical welfare depends on this matter. We are
not speaking here of food for the sick, but of food for the well, not of
special delicacies, but of the every-day food of the average household
the practical subject for the practical man, woman or child. Let us see
what we may learn from the researches of the wisest students who have
considered the subject. It is not necessary here to go into the chemical
analysis which has proved the following facts, for facts they are. They
may be accepted absolutely as safe guides, with the assurance that only
benefit can result.
The popular division of foods into animal and vegetable is neither
scientific nor satisfactory. Not that it is a matter of indifference
whether man lives on a purely animal or purely vegetable diet or on one
derived from both kingdoms, but the differences depend not on the source
whence the foods are obtained, but on the proportions in which the
various food elements are combined, and on the digestibility and other
special properties of the foods selected. The materials supplied in the
form of food, and digested and absorbed by the body, are partly employed
for building up growing organs and making good the wear and tear—the
loss of substances—which they are constantly undergoing, and partly as
fuel for the production of heat and of energy.
Speaking roughly, raw meat of ordinary quality consists of water
seventy-five per cent, albumen and nitrogenous matters twenty per cent,
and fat five per cent. Although meat becomes more tender by keeping, it
is more wholesome while fresh, and freshness should not be sacrificed
for a tenderness really due to the beginning of decomposition. The flesh
of mature cattle, that is, four or five years old, is more nutritious
than that of younger ones. It is a matter of experience that beef and
mutton are more easily digested than veal and pork. Veal broth, however,
contains more nutritious matter than mutton broth or beef tea. Poultry
and wild birds, if young, yield a tender and digestible meat. Fish vary
much in their digestibility, salmon, for instance, being utterly unfit
for weak stomachs. Crabs and lobsters are notoriously indigestible.
Milk is the sole nourishment provided by nature for the young of man and
beast, and contains all food stuffs in the best proportions for the
infant’s needs. But milk alone is not adapted to the adult. Supplemented
by other food, however, it is invaluable and not appreciated as it ought
to be. Cheese is highly nutritious, but not very digestible. Eggs
resemble milk in composition, except that they contain less water. The
nearer raw the more digestible they are, and the yolk is more so than
the white, which, when hard boiled, is the most indigestible form of
albumen known. The addition of eggs to baked puddings is of questionable
utility, and next to a raw egg, well beaten, in milk or water or in soup
or beef tea, not too hot, a light boiled custard is the best form for
invalids.
From the earliest ages the grains or cereals have formed a portion of
man’s diet. Wheat has always been the most esteemed, and some varieties
of it may be grown in every climate except the very hottest and coldest.
Barley, rye and oats may be grown much farther north, but are less
digestible. Oatmeal cannot be made into bread, rye bread is rapidly
being displaced by wheat, and barley has almost entirely fallen into
disuse, except for the purposes of the brewer and distiller. In the
tropics rice is the chief cereal. It consists almost entirely of starch,
and is thus unfit for bread making. Our own corn, which we inherit from
the Indians and have immensely improved, is of all the cereals the
nearest approach to a perfect food.
Among roots the potato holds the most prominent place. Potatoes are
wholesome only when the starch granules, which compose them, are
healthy, as shown by their swelling out during boiling, bursting their
covering, and converting themselves into a floury mass, easily broken
up. They contain from twenty to twenty-five per cent of nutriment, but
this is almost entirely starch, and as a food in combination with meat,
cheese or other vegetables, they are not equal to rice. Parsnips, beets
and carrots are wholesome and nutritious, and should be used much more
than they are. Turnips are not so valuable. Cabbages and their kindred
have but little food value, although the salts they contain are
excellent in the preservation of health. As regards green vegetables in
general the importance of having them fresh is not sufficiently
realized. When they have been cut some days changes occur just as truly
as in animal food, and the freshness should be carefully watched, except
with those specially adapted for storing.
Salads are useful in maintaining the health, although many of them are
very indigestible, those of radishes, celery and cucumbers among the
list. Fruits are prized chiefly for their taste. Grapes alone, among
fresh fruits, contain any large proportion of food stuff. As an aid to
digestion, however, they all are properly highly prized. Fruits should
be fully ripe, but without any trace of decomposition.
Stimulants and condiments of high seasoning have little food value of
their own, but they have value as aids to digestion when used
moderately, and in making simpler foods more palatable. Alcoholic
liquors, whether mild or strong, hardly need to be considered here. It
is to be gravely doubted if such beverages are ever necessary or of
value in the diet, and in this place we are not considering them from
any other point of view.
It is equally difficult to speak positively and generally in reference
to tea and coffee. It is safe to say, however, that many people drink
these tempting beverages to excess, with harm resulting to themselves
from it. Tea and coffee alike act as exciters of the nerve centers,
accelerating and strengthening the heart’s action and respiration,
causing wakefulness, and increasing the secretion of the kidneys and
skin. Tea and coffee are far superior to alcohol in enabling man to
resist the depressing influence of fatigue and exposure to cold, and are
admirably adapted to the needs of soldiers on the march or men on
outdoor night duty. Cocoa, chocolate and their preparations contain some
active elements similar to those of tea and coffee, but the proportion
of nutritive material is so much greater that they are to be looked on
rather as food than drink.
The considerable use of ice and iced drinks is to be avoided. Small
quantities are of service in relieving thirst and vomiting, and in
cooling the body when exposed to great heat. But since ice causes the
mucous membrane of the stomach to become temporarily pale and bloodless,
it checks or altogether suspends the flow of the gastric juice. Thus
iced drinks at meals interfere seriously with digestion. Observe also
that there is no truth in the popular notion that frozen water or ice is
always pure. Water is not purified by freezing, and may be even more
polluted than it was before.