The History Of Vitamins
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THE HISTORY, USE AND EFFECTIVENESS OF
VITAMINS AND NUTRIENT SUPPLEMENTS
A Vitamin is any organic compound required by the body in small amounts for metabolism, to
protect health, and for proper growth in children. Vitamins also assist in the formation of
hormones, blood cells, the chemicals of the nervous-system, and genetic material. The
various vitamins are not chemically related, and most differ in their physiological
actions. They generally act as catalysts, combining with proteins to create metabolically
active enzymes that in turn produce hundreds of important chemical reactions throughout the
body. Without vitamins, many of these reactions would slow down or stop. The intricate ways
in which vitamins act on the body, however, are still far from clear. The 13
well-identified vitamins are classified according to their ability to be absorbed in fat or
water. The fat-soluble vitamins A, D, E, and K are generally consumed along with
fat-containing foods, and because they can be stored in the bodys fat, they do not have to
be consumed every day. The water-soluble vitamins, the eight B vitamins and vitamin C,
cannot be stored and must be consumed frequently, preferably every day. The body can
manufacture only vitamin D, all others must be derived from the diet. Lack of them causes a
wide range of metabolic and other dysfunctions. In 21″the U.S., since 1940, the Food and
Nutrition Board of the National Research Council has published recommended dietary
allowances for vitamins, minerals, and other nutrients”. Expressed in milligrams or
international units for adults and children of normal health, these recommendations are
useful guidelines not only for professionals in nutrition
(Pg 18) but also for the growing number of families and individuals who eat irregular meals and rely on prepared foods, many of which are now required to carry nutritional labeling.
A well-balanced diet contains all the necessary vitamins, and most individuals who follow
such a diet can correct any previous vitamin deficiencies. However, persons who are on
special diets, who are suffering from intestinal disorders that prevent normal absorption
of nutrients, or who are pregnant or lactating may need particular vitamin supplements to
bolster their metabolism. Beyond such real needs, vitamin supplements are also often
believed to offer ocureso for many diseases, from colds to cancer; but in fact the body
quickly eliminates most of these preparations without absorbing them. In addition, the
fat-soluble vitamins can block the effect of other vitamins and even cause severe poisoning
when taken in excess. Vitamin A is a pale yellow primary alcohol derived from carotene. It
affects the formation and maintenance of skin, mucous membranes, bones, and teeth, vision,
and reproduction. An early deficiency symptom is night blindness which is the difficulty in
adapting to darkness. Other symptoms are excessive skin dryness, lack of mucous membrane
secretion, causing susceptibility to bacterial invasion, and dryness of the eyes due to a
malfunctioning of the tear glands, a major cause of blindness in children in developing
countries. The body obtains vitamin A in two ways. One is by manufacturing it from
carotene, a vitamin precursor found in such vegetables as carrots, broccoli, squash,
spinach, kale, and sweet potatoes. The other is by absorbing ready-made vitamin A from
plant-eating organisms. In animal form, vitamin A
(Pg 19)
is found in milk, butter, cheese, egg yolk, liver, and fish-liver oil. Although one-third of American children are believed to consume less than the recommended allowance of vitamin A, sufficient amounts can be obtained in a normally balanced diet rather than through supplements. Excess vitamin A can interfere with growth, stop menstruation, damage red blood corpuscles, and cause skin rashes, headaches, nausea, and jaundice. Known also as vitamin B complex, these are fragile, water-soluble substances, several of which are particularly important to carbohydrate metabolism.
Thiamine, or vitamin B1, a colorless, crystalline substance, acts as a catalyst in
carbohydrate metabolism, enabling pyruvic acid to be absorbed and carbohydrates to release
their energy. Thiamine also plays a role in the synthesis of nerve-regulating substances.
Deficiency in thiamine causes beriberi, which is characterized by muscular weakness,
swelling of the heart, and leg cramps and may, in severe cases, lead to heart failure and
death. Many foods contain thiamine, but few supply it in concentrated amounts. Foods
richest in thiamine are pork, organ meats such as liver, heart, and kidney, brewers yeast,
lean meats, eggs, leafy green vegetables,