Vitamins

What are vitamins?

Vitamins are organic compounds or essential micronutrients that are found in various types of foods and are necessary for the growth and good health of animals including humans. Vitamins are accessory dietary factors and are only necessary for very small amounts.

In addition to oxygen, water, proteins, fats, carbohydrate, and certain inorganic salts, vitamins are also necessary for our life. It cannot be produced by our body. Hence, we need to intake foods or supplements that contain various vitamins. However, vitamin D may be supplied in food or may be produced in the skin by irradiation of ultraviolet-visible light from the sun.

Most vitamins do not contain a single molecule but contain a group of related molecules. Therefore, they are called vitamers. For example, eight vitamers are found in vitamin E, four tocopherols, and four tocotrienols. In B₆, six related molecules are found.

Classification

The vitamins have been arbitrarily classified into two groups, fat-soluble or water-soluble. Four are fat-soluble (A, D, E, and K) and nine are water-soluble (8 B vitamins and vitamin C) among 13 vitamins found in humans.

Fat-soluble vitamins

Fat-soluble vitamin is an essential micronutrient soluble in fat and found in many plant and animal foods and in dietary supplements. They are absorbed along with fats in our diet and are stored in our body’s fatty tissue and in the liver. These may include,

1. Vitamin A (Retinol)
2. D (Cholecalciferol, Ergocalciferol)
3. E (Tocopherols, Tocotrienols)
4. K (Phylloquinone, Menaquinones)

Water soluble vitamin

The nine water-soluble vitamins are found in the human diet. These may include,

1. Vitamin B₁ (thiamine)
2. Vitamin B₂ (riboflavin)
3. Vitamin B₃ (niacin)
4. Vitamin B₅ (pantothenic acid)
5. Vitamin B₆ (pyridoxine, pyridoxamine, pyridoxal)
6. Vitamin B₇ (biotin)
7. Vitamin B₉ (folates, folic acid)
8. Vitamin B₁₂ (cyanocobalamin, hydroxocobalamin, methylcobalamin, adenosylcobalamin)
9. Vitamin C (ascorbic acid)

Uses, sources, biological functions, supplements, side effects, and many more about various vitamins are given below the individual topics in this category,