Vitamin

There are 13 organic compounds (thus excluding trace minerals) essential to human life in very small amounts. Eleven of these must be supplied in the diet (vitamins A, B1, B2, B6, B12, C, E, K, folic acid, biotin and pantothenic acid); two (niacin and vitamin d) can be made in the body if there is sufficient of the amino acid, tryptophan, and sunlight, respectively.The word may be pronounced either veitamin or vittamin. Vitamins A, D, E and K are grouped together as fat-soluble vitamins, because they are soluble in lipids, but not in water. Vitamin C and the B vitamins (includingantothenic acid, biotin and folic acid) are grouped together as the watersoluble vitamins since they are all soluble in water, but not lipids.