176 Vitamins in Human Nutrition
lion. It is about 100 times less abundant in foods considered
rich in it than is vitamin C in foods in which it is rich. On
the other hand, very much smaller amounts are required, it is
more widely distributed in common foods, and it is not
nearly so easily destroyed.
Two to three pounds of food averaging one part of thia-
min per million would cover human needs. Such foods sup-
ply about 7 units per ounce. The only common foods which
average more than 20 units per ounce are various whole
grains; liver, heart, and kidneys of various animals; bacon,
ham, and sausage among pork products; egg yolk; malted
milk powder; green asparagus, string beans, dried beans,
lentils, peas, and parsnips among vegetables; and various
nuts. Whole wheat bread supplies just about 20 units per
ounce, rye bread slightly less. From 7 to 20 units per ounce
is afforded by lean meats and fish, whole eggs, milk, and a
large variety of vegetables and fruits.
Although the actual content of vitamin B1 in most fruits
is relatively low compared with that of whole grains, nuts,
and some vegetables, fresh fruits are nevertheless an im-
portant source because of the quantity in which they are
eaten and the fact that they are eaten without any cooking
or other manipulation which might reduce the vitamins they
contain. Yeast is particularly rich in thiamin, but the amount
of yeast used in making bread is too small to be of any
significance. Wheat germ contains the entire daily require-
ment of a human being in half an ounce. Prepared bran is
only one-fifth as rich in thiamin as is the germ. Oats also
contain a relatively large amount.
Polished rice, white flour, and degerminated corn meal
and hominy have almost none, but when rice is soaked and
parboiled before being milled, the thiamin and phosphorus
soak into the starchy part from the hulls and are thereby