A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be produced in sufficient quantities by the body and must be obtained from the diet. For example, ascorbic acid (vitamin C) ,biotin and vitamin D are required in the human diet. Thirteen vitamins are presently universally recognized.
Vitamins have diverse biochemical functions. Some have hormone-like functions as regulators of mineral metabolism or regulators of cell and tissue growth and differentiation, others function as antioxidants . The largest number of vitamins function as precursors for enzyme cofactors, that promote enzymatic activity to facilitate metabolism.
Vitamin and Food source
Vitamin A (Retinol) Cod liver oil
Vitamin B1 (Thiamine) Rice bran
Vitamin C (Ascorbic acid) Citrus, most fresh foods
Vitamin D (Calciferol) Cod liver oil
Vitamin B2 (Riboflavin) Meat, eggs
Vitamin E (Tocopherol) Wheat germ oil, unrefined vegetable oils
Vitamin B12 (Cobalamins) Liver, eggs, animal products
Vitamin K (Phylloquinone/phytol naphthoquinone) Leafy green vegetables
Vitamin B5 (Pantothenic acid) Meats, whole grains, in many foods
Vitamin B7 (Biotin) Meats, dairy products, eggs
Vitamin B6 (Pyridoxine) Meat, dairy products.
Vitamin B3 (Niacin) Meat, eggs, grains
Vitamin B9 (Folic acid) Leafy green vegetables