Niacin: Nicotinic acid, one of the B-complex vitamins-B 3. Deficiency of niacin in the diet results in the disease pellagra. See: Pellagra. From Nutrition and Healthy Eating Resources NSCLC Nutrition & Appetite, Explained Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew References Medically reviewed by Martin Zipser, MD; Board Certified: Surgery
