Evening star. [volume] (Washington, D.C.) 1854-1972, 1932-01-19
STUDY EXTENDS
D|ETET|c SCIENCE
Results of Study to Find
Proper Load Balance
& Announced.
BY THOMAS r.. HENRY.

Some of the commonest foods which
everybody eats every day and which are
essential to life contain physiologically
active compounds which must be nicely
balanced to preserve the health of the
organism.
These substances themselves are nee
essary constituents of diet, parts OF the
great complex Of chemical substances
which are taken from food by the d.
gestive process and used to build up
tissue Extended disbalance Of the sub
stances In the diet may go far to ex-
plain some obscure diseases which are
considered due to dietary insuficiency.
These are conclusions from an ex-
tensive study conducted at the National
Institute of Health here by Drs. M. x.
Sullivan and w. c. Hess now OF the
Chemo- Medical Research Institute,
Georgetown University and Past Assist
ant Surgeon w. H. Sebrel of the United
states Public Health Service. These
studies promise to provide new chap
ter in the science of dietetics, or the
food requirements of the body.
Kinds of Food.
THE balanced diet, 1t has long been
known. must consist of three kinds OF
II must also contain proper mineral
matter and have all the vitaminS dis
tributed through these food substances.
otherwise far-reaching i'll effects on the
general health are likely. But all three
Are quite complex in themselves ana
foods differ in their constituents.
DIR. sullivan and his co-workers nave
been studying the constituents OF SIN
ole one of the major food classifications,
fhe proteins. These are obtained chieny
from meat, fish, eggs, cereals AND, IN
lesser amounts, from nearly all foods'
When they are digested wide variety
Of substances known as amino aclds,
10 in all, are liberated from them.
These amino-acids are essential LOT
building up tissue. They are parts o,
the tremendously complex cnemlcai
structure of the body. Each ammo
acid presumably has Its own enect;
Thev can be extracted in the chemical
laboratory as well as in the body.
Z DIR. sullivan and his co-workers tried
arbitrarily increasing and decreasing
tlne amounts of various amino-acids n
the diet of rats. They fed the animals
On diet with the minimum amount
al proteins on which 1t was possible 70
maintain a measurable growth. Inc
bulk of this diet was made up OF the
carbohydrate, cornstarch. They re-
yIaced some of the cornstarch with
various amounts of specific amino
acids obtained in the laboratory.
Source of Sulphur.
One of the most important OF the
snino-acids is cystine. Some OF IL Is
present in all protein fooos. IL Is Inc
Chief source of sulphur in the nooy.
The greatest amounts OF cystne are
sound In the hair and nails. 1t must
al ne extracted from the food. The
exnerimenters added enough free cys-
tine to compose 20 per cent OF the total
dset The rats died in from three 70
Ave DAYS. TIER livers and kidneys were
found badly injured.
Similar results occurred with 10 per
cent cystine. Five per cent was much
less toxic. ~
Another amino-acid present In all
protein foods, in various amounts Is
tvrosine. Rats given diet 70 per
cent of which consisted of free tyroslne
died in from five to six days. Inc
poison effects were obvious. The eyes
were closed and the rats apparently
blind. The legs we're red and swollen
and the animals dragged their hind legs
as they crawled The intestines con-
Timed an unknown reddish-black mate
riaf. Rats given the same amounts OF
the emino-acid tryptophane died In
from 8 to IL days after rapid loss OF
weight. The amino-acid lysine also
caused loss of weight, but the only
rat killed lived for 80 days.
Even 10 and per cent tyrosine
showed decidedly toxic effects.
Whereas S per cent tyrosine killed
the rats in eight days, the rats on the
basal diet plus per cent tyrosine and
per cent cystine lived 10, SO and II
days and the fourth was killed on the
18TH day.
Offset Each Other.
There was clear evidence that the
substances, both essential and both
poisonous, we're offsetting each other.
Tyrosine in some way prevented the
injurious effects of cystine on the liver
and kidneys and cyStine prevented the
blindness and partial paralysis caused
by tyrosine.
Different proteins. DR.. Sullivan ex-
plains, contain different amounts OF
these amino acids which proved poison
Gus when used alone. A food that has
them well balanced is the better food.
Lack of balance in the diet would throw
q strain on the tissues Of the body.
The body's supply Of any OF these
animo-acids Is limited. They must be