Evening star., 1937-11-04
STARS, MEN AND ATOMS
of Science Progress
laboratory and Study
BY THOMAS r. HENRY.

The extremely rare element cobalt may
be essential in human diet.
Evidence for this was presented before
the American Dietetic Association meet
ing in Richmond last week by DR. R. V.
McCollum of Johns Hopkins University.
The element seems to play some part in
sugar metabolism and lack of it may pro-
duce severe anemias it is shown by
tests with experimental animals.
Considerable amounts of the element,
DR.. McCollum said, are found in inslllin
preparations, and simultaneous injection
of small quantities of cobalt and insulin
into rabbits or dogs markedly increased
the action of insulin on the blood sugar.
The anemia- producing effect is quite OBJ
scure, but it has recently been found
that peculiar disease of sheep in Aus
tralia, characterized by deterioration of
red blood cells and loss of weight and
appetite, is relieved by administration of
the element.
The indications are, DR.. McCollum
said, that extremely minute amounts of
cobalt are necessary in the diet They
would be contained in the average meal.
Altogether, Dr. McCollum said, ap-
proximately 40 elements are found in
the animal body. OF these 13 appear to
be essential to physiological processes
and must be included in the diet. They
are: Sodium, potassium, calcium, mag
nesium, chlorine, iodine, phosphorus.
sulphur, iron, manganese, copper, zinc
and cobalt. If any of these elements is
omitted from an otherwise adequate diet
failure of nutrition will supervene.
Tho carO1H UrOi1f, Of i,,oyuo l., ,1o,.,o
found in the body, the functions of
which are unknown, includes: Aluminium,
antimony, arsenic, barium, bismuth.
boron, bromine, cesium, chromium, flu
rorine, germanium, gold, lead, lithium,
mercury, nickel, rubidium, selenium.
silica, silver, strontium, tin, titanium and
vanadium.
Of the necessary elements the ordinary
diet Is most likely to be deficient in iron.
Only minute amount is needed. The
generally assumed requirement is less
than two one-hundredths. of a gram a
day for the average individual It would
be hard to make up a diet which did not
include at least this much
Nevertheless recent DEVELOPMENTS in
dicate that iron hunger probably has
been widespread. Only special forms of
the element can be made use of in
physiological processes. Thus, DR.. Nc
Collum pointed out, less than half the
iron in wheat and oats is in such a form
that the body can make use of it.
Moreover, the availability of iron
seams to be tied up in some way with the
amount of calcium in the diet. A char
acteristic anemia was produced in rats
by reducing the iron content of the diet.
together with the amount of some of
the necessary salts. It was found that
administration of iron alone did not
greatly improve this anemic condition.
but when sufficient calcium was given the
Improvement was marked, although this
element had no direct effect on the blood
cell count.
Very minute amounts of copper also are
essential for the proper metabolism of
iron. Ordinarily the diet contains plenty
of this element which is widely distrib-
uted in plant and animal material The
deficiency is chiefly encountered in
anemic conditions of infants.
Perhaps the most curious effects are
found in deficiency of manganese first
detected by DR.. McCollum and his CO.
workers about eight years ago. The out
standing result seems to be loss of ma
ternal affection. Female rats entirely
deprived of the element failed to suckle
their young. They appeared Indifferent
to them. The young themselves did
poorly even when raised by foster
mothers with an adequate amount Of