Vitamins : Introduction, Characteristics, Chemical Composition

Vitamins : Introduction, Characteristics, Chemical Composition
Vitamins : Introduction, Characteristics, Chemical Composition

Hopkins observed that food contains a number of significant chemical compounds that are crucial for maintaining good health. Funk (1912) used the term VitaminsStudy of Vitamins is called "Vitaminology."

Hopkins and Funk (1912) presented the "Vitamin Theory" and stated that every such disease is caused by the deficiency of some particular vitamin in the diet.

Like micro-minerals, vitamins are also essential in very minute amounts (milligrams or micrograms) for the normal metabolism of the animal body. Although they do not provide energy, they control the synthesis and proper utilization of other "fuel" substances. Therefore, due to their deficiency, the metabolism becomes defective and makes the body sick. That is why these are called "growth factors" and the diseases caused by their deficiency are called deficiency diseases.

General Characteristics of Vitamins
 ➤  Only small amounts of vitamins are needed.

 ➤  They cause marked physiological effects.

 ➤  Almost of all the vitamins have complex chemical structure except a few, like nicotine acid and p- aminobenzoic acid.

 ➤  The possess high specificity of function i.e., each vitamin is related to a definite disease which is caused by its deficiency. Its cure is effected only a supply of the same vitamin.

 ➤  Animals and other living things cannot produce them, thus food must be used to supply them.

 ➤  They have catalytic action.

 ➤  Vitamins are non-antigenic.

 ➤  They carry out functions in very low concentration. Their total dietary requirement is very low.

 ➤  Vitamins are widespread in nature.

 ➤  Plants can synthesize all the vitamins whereas animals synthesize only in a few of them.

 ➤  Human body can synthesize only vitamin A and B.

 ➤  More than one vitamin can be found in all common foods.

 ➤  Vitamins are partly destroyed and partly excreted.

 ➤  Most of the vitamins have been artificially synthesized.

 ➤  Synthetic vitamins are as effective as the natural vitamins.

Chemical Composition
 ➤  Vitamins are organic compounds of different chemical nature. These are alcohols, aldehydes, organic acids, their derivatives or nucleotide derivative.

Classification of Vitamins
 ➤  About 20 types of vitamins have been discovered so far in living organisms. Two of these, niacin and vitamin D, are synthesized in our body, but the rest must be present in our diet.

All vitamins are divided into two main categories - soluble in water and soluble in fats.

1. Vitamin A, D, E and K are fat soluble
2. Vitamin B complex and vitamin C are water soluble.

Excess amounts of water-soluble vitamins are excreted in the urine. Therefore, there is no special accumulation of these in the body and it is necessary to take them from food every day. In contrast, fat soluble vitamins are not excreted with urine. Therefore, there is some accumulation of these in the adipose tissue, due to which it is not necessary to take them daily from food.

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