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. Vitamin is an essential dietary factor and is only necessary for very small amounts.

Vitamins (A, D, E, B vitamins and vitamin C) Sources with Definition, Classification and Examples

In addition to oxygen, water, proteins, fats, carbohydrates, and certain inorganic salts, vitamin is 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.


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 these, 13 are found in humans.

Fat-Soluble Vitamins

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

Choline supplement with B-complex vitamin, food sources, functions, and benefits in human health


What is Choline? Choline is a quaternary ammonium cation that is naturally available in many foods and dietary supplements. The dietary supplements of choline obtain...
Pyridoxine is a form of vitamin B6 supplement, uses, side effects


What is Pyridoxine? Pyridoxine is a form of vitamin B6 found in various foods and used as a dietary supplement to metabolize amino acids, carbohydrates,...
B vitamins list, sources, functions of B complex vitamin such as thiamine, riboflavin, B3, B5, B7, folic acid, and B12 with supplements

B Vitamins

What are B Vitamins? B vitamins are a list of water-soluble vitamins that mainly help the body convert food into energy and synthesis hemoglobin. B...
Vitamins and Minerals list with food sources, essential biological functions and multivitamins supplements for the healthy body

Vitamins and Minerals

Essential Vitamins and Minerals Vitamins and minerals are lists of essential micronutrients that use our body to carry out a range of normal biological functions....
Vitamin E uses, benefits for skin, hair, vision, menopause, immune system with natural dietary supplements and deficiency

Vitamin E

What is Vitamin E? Vitamin E is a fat-soluble vitamin and a powerful antioxidant that is beneficial for immune health and cellular signaling in your...
Vitamin B5 (pantothenic acid) benefits to skin, hair and nerve with B5-reached foods and supplements, deficiency effects on health

Vitamin B5

Vitamin B5 (Pantothenic Acid) Vitamin B5 (Pantothenic Acid) is a water-soluble B vitamin present naturally in various foods and available as a supplement. In general,...
Vitamin K uses and benefits of vitamin K1 (phylloquinone) and vitamin K2 (menaquinones) with sources and deficiency symptoms

Vitamin K

What is Vitamin K? Vitamin K is a fat-soluble vitamin that helps to make various proteins that are needed for blood clotting and the binding...
Vitamin B7 (Biotin) or vitamin H sources foods rich in biotin with uses, supplement, benefits, and deficiency

Vitamin B7

Vitamin B7 (Biotin) Vitamin B7 (Biotin) or Vitamin H is one of the B vitamins that is found in various natural food sources and supplements....
Niacinamide or Nicotinamide (NAM) and Nicotinic acid or Niacin (vitamin B3) supplements and serum for Skin with Uses, Benifits


What is Niacinamide? Niacinamide or Nicotinamide (NAM) is a water-soluble form of vitamin B3 or niacin. The crystalline powder and niacinamide serum are used in...
Vitamin B3 sources and supplements of Niacin, Nicotinamide, and Nicotinamide riboside with benefits, uses and deficiency

Vitamin B3

Vitamin B3 (Niacin) Vitamin B3 (Niacin) is a water-soluble B vitamin found naturally in some foods and sold as a supplement. Nicotinamide (niacinamide), niacin (nicotinic...