Complete Book of Vitamins

ISBN: 9780878571765

定价: 129.00

内容简介

CHAPTER 1
Vitamins: What They Are
and What They Do
Despite all the talk about vitamins today??? few people actually
know what they are and why they are so important. Vitamin re-
search goes on constantly??? new discoveries are reported from
time to time??? but scientists are all too aware that they don t know
all of the facts about all of the vitamins. Today 15 vitamins have
been recognized and analyzed. Scientists believe that again as
many probably exist and are essential for our health.
Vitamins are organic food substances--that is??? substances
that occur naturally only in living things??? plant or animal. They
exist in foods in minute quantities; they are absolutely necessary
for proper growth and the maintenance of health. Plants manu-
facture their own vitamins. Animals obtain theirs from plants or
from other animals that eat plants. Some animals manufacture in
their own bodies some of the vitamins they need.
It was around the turn of the century that someone first
suspected there might be more in foodstuffs than fats??? proteins???
carbohydrates??? and minerals. Laboratory experiments showed
that even when all those elements were present in the diet??? labo-
ratory animals could still die of malnutrition. Scientists began to
search for this important missing link. They discovered vi-
tamins. The name comes from vita (life) plus amine (the
chemical compounds that were originally thought to be vi-
tamins). 3