niacin science definition

A water-soluble organic acid belonging to the vitamin B complex that is important in carbohydrate metabolism. It is a pyridine derivative and is a precursor of the coenzyme NAD. Niacin is found in liver, fish, and whole-grain foods. Deficiency of niacin in the diet causes pellagra . Also called nicotinic acid. Chemical formula: C₆H₅NO₂.