NIACIN – (NICOTINIC ACID, NICOTINAMIDE, ANTIPELLAGRA VITAMIN, VITAMIN B3) – Dietary Sources
Nicotinic acid forms an integral part of nicotinamide adenine dinucleotide (NAD) and its phosphate (NADP) which acts as coenzymes in the metabolic pathways of glucose and proteins. Nicotinic acid and nicotinamide have equal biological potency and are together referred to as niacin. Tryptophan is converted into niacin in the body, 60 mg of tryptophan giving rise to 1 mg niacin.
Dietary sources include liver, pulses, whole cereals, fish, meat, groundnuts, milk, eggs, and to a smaller extent, vegetables. Coffee contains appreciable amounts of this vitamin. Rice and other cereals contain this vitamin, major portion of which is lost by milling. In maize niacin is present in an unabsorbable form ‘niacytin’. Moreover, maize is poor in its content of tryptophan. One-fourth of the vitamin may be lost in washing and cooking, though cooking alone does not destroy it. Daily requirement is 6 mg/1000 kcals (15-18 mg/day). Deficiency of niacin causes pellagra.