The Yale expositor., 1914-07-02
LESSONS IN
A .@
DOMESTIC SCIENCE
Prepared by the
Agricultural Department
WASHINGTON, D. c.
FOOD VALUES.

many women, and the mere mention
of a carbohydrate" or a protein"
will make them skip over the page
or drop the book. to turn to some
more familiar subject. AS a matter
nutrition are quite simple, and may
be easily understood by all. Farmers
Bulletin 142, which will be sent on APP
plication to the United States de-
partment Of agriculture, Washington,
D. c., discusses the general principles
OF nutrition, as we'll as a number of
the more important phases of the sub
ject, with special reference to the re-
suits obtained in the department IN
vestigations and the closely related
work OF the agricultural experiment
stations.
Our bodies may be likened to an
engine, and the food We eat to the
fuel used in the engine. We all know
that engines must be supplied with
coal wood, or some other fuel before
they can be made to perform any
work When the fuel combines with
oxygen of the air, the familiar process
of burning, heat is liberated. and the
energy which was stored up in an
inactive form in the fuel is changed
into an active form. giving the ma
chine power to fulfill its purpose. In
a similar way our muscles, tissues and
organs gain power to accomplish their
various functions from the energy
stored up in food
OF the many varieties of fuel TO be
had, some produce more energy than
others. For example, coal containing
a large amount Of slate is not capable
of supplying as much heat and power
as coal which is free from slate. SINH
larly, some foods have an advantage
over others in their ability to supply
the body with a maximum amount of
heat and energy. Again, engines with
large CRATES require large Jumps of
coal while those with small CRATES
burn small pieces to better advantage.
The same principle holds true for
food. man at hard labor needing a
diet quite unlike that required by a
man leading a sedentary life.
Food as we buy it consists OF an
edible portion, which contains water
and the nutrients. and of refuse, such
as bones, entrails and shells. The
nutrients are classified as proteins,
fats, carbohydrates and mineral mat
ters. Protein Is familiar to us in the
lean and gristle of meat. the white of
eggs, and the gluten OF wheat; fats
occur chiefly in the animal foods, as
meats, fish and butter, but are also
found in olives, cotton seed, nuts. and
in such cereals as oatmeal and maize;
carbohydrates include such COM
pounds as starches. different kinds Of
sugar and the fiber OF plants, and are
found chiefly in the vegetable foods
as the cereal grains and potatoes.
These nutrients when taken into the
body furnish the materials for the
repair and growth of the various It's
sues, and also supply our bodies with
heat and our muscles and organs with
energy, or the power to do work.
In its building function protein is
the most important ingredient of food,
as il is the basis of muscle, bone and
almost all the tissues and fluids OF
the body. Mineral matters are also
needed in the body structure, though
in smaller quantities. Protein, fats.
and carbohydrates may any OF them
produce heat or muscular energy, but
protein has another and very i'm
portant function, namely, to build and
repair body tissue. We depend
on the fats and carbohydrates chiefly
to supply the heat and muscular en-
ergy, and use protein for it's indis-
pensable work of tissue forming,
though 1t does even then supply en-
ergy also.
Food as we eat it is not generally
in a condition to be used by the body.
1t must first be digested, a process
which takes place partly in the stom-
ach, but more in the intestine. The
useless portions of the food are sepa-
rated and rejected, while the parts
which can serve as nutriment are
changed into forms In which they can
be absorbed through the walls OF the
stomach and intestine, taken into the
circulation and carried by the blood
all over the body to supply to the
organs and tissues, the materials and
energy which they need to perform
their various functions. At the same
time the wastes which the exercise of
these functions has produced are car
ried away by the blood to the kid
neys, the bowels, the lungs and the
pores of the skin, through which they
are removed from the body.
The saliva has some power of
changing insoluble starches into solu-
BILE sugars, but as food stays in the
mouth only a short time, there Is gen.
orally little chance for such action
there, and the necessary change takes
place later In the intestine which is
also equipped for this purpose The
saliva, also makes the food easy to
swallow and helps to At the food to
be more easily worked on by the
stomach by moistening II. The gastric
juice OF the stomach acts upon the
protein. and the pancreatic juice OF
the intestine upon the protein. fats
and carbohydrates. The action OF all