Evening star., 1935-12-15
CALCIUM SHOWN
EXTENDING LIFE
Experiments With Rats Ex-
pIode Old Theory About
Fast Growth.
BY THOMAS r. HENRY.


This significant discovery is reported
in the annual year book OF the Car
negie Institution of Washington, is
sued yesterday, by Prof. H. c. Sherman
of Columbia University, who has been
working under an institution grant.
DR.. Sherman has been feeding rats
on two carefully prepared diets-ootn
containing everything essential to life
and good health. The first diet was
good one Rats fed upon it exclusively
thrived, lived lives of normal length,
and the line has been continued
through 81 generations,
Second Rich in Calcium.
The second diet was a richer mix
ture. The rats fed upon it were
healthier. grew faster and lived longer.
The experiments reported here were
designed by a process Of elimination, to
find Just what was in the second diet
to contribute to longevity. They have
proved that calcium is, at least, a
major factor.
The first diet, upon which the rats
lived normally healthy lives, contained
20 per cent of calcium by bulk. The
content of this element was increased
to IS per cent, with the result that
large part of the extra life span at
tanned by the rats on the second diet
was duplicated by those fed on the
calcium enriched first diet.
More than 200 rats fed on the two
mixtures now have completed their life
spans from birth to death. Not only
was life longer with the calcium diet,
but growth was faster and there was
increased adult vitality One of the
major jobs in validating the evidence
was to make allowances for normal
differences in the life spans of indi-
viduals but this was accomplished
successfully.
Old Theory Exploded.
Besides demonstrating the great
value of calcium, the experiment en-
abled DR.. Sherman to explode an
old theory that seemed to have some
scientific validity-that fast growth is
in some way associated with short
life. Growth rates were determined
for two periods-the first and second
four weeks of life. These, DR.. Sher-
man says, are analogous to the periods
Of infancy and childhood in human
beings The determinations show, he
says, "that differences in rate of
growth and length of life among indi-
viduals of the same sex on the same
diet are independent of each other.
Slower or more rapid growth, as an
oI,o
measurably predispose to a longer or
shorter life under normal conditions
Of nutrition"
Rats have much the same phySio-
logical history as human beings, ex-
cept that it is telescoped into shorter
period, in which effects of various
factors both on individual and on
future generations more easily can be
noted DR. Sherman's laboratory rats
have better diet, taken as a whole.
than that of many American fam
lilies. One of his experiments, Just
reported, has been actually to feed
his laboratory animals on just such
diet as is frequently met with in
fairly well-to-do households.
Orange Juice in Diet.
This diet consisted of 10 per cent
OF dried lean beef, 8 per cent of
dried potato, per cent of dried
orange juice, per cent of dried whole
milk, per cent of lard, per cent
of ground whole meat 40 per cent of
white flour, IL per cent of sugar, and
per cent of butter fat. Such a diet,
presumably, contains the necessary
factors for good health. 1t differs
chiefly from the laboratory rat diet
in a deficiency of calcium. 1t is, of
course, much better diet than that
sof thousands of American families.
The first generation of animals fed
on this human diet seemed to thrive
normally. But, presumably because of
the diet itself, the line ended with the
second generation. No third genera
ton was born. Analysis of represen-
tative members of the second genera
ton showed them to have a slightly
Sub-normal content of body calcium.
Moreover, the bones contained
slightly lower proportion of the total
body calcium than in animals of the
coALC dSC WA1OSC u1Gdhc Ol ILLS el6-
ment had been more liberal.
New Experiments Started.
1t is not assumed that human beings
will react in the same way as the rats.
The findings, however, are so sug-
gestive that new experiments have
been started with some of the food
materials in what are presumably more
favorable proportions, corresponding
with the moderate improvement of the
average American food habit under
the influence of newer knowledge of
nutrition. In addition, the rats will
be given calcium to correspond with
the average drinking water supply. In
the laboratory they drink only dis
titled water, so that no element of
uncertainty will be added to their
diets
Milk, of all the foods used by man.
Is richest in calcium. according to
dieticians. Fruits are also an i'm
portant source of calcium supply.
The annual research exhibit of the
institution, illustrating the outstanding
results Of scientific work during the
year, was opened to the public yes
terday and will continue open today
and tomorrow. There is a series of
lectures each day explaining the
exhibits.