Niacin, also called vitamin B3, is a water-soluble vitamin that is found naturally in foods, is added to processed foods, and can be bought as a supplement. Niacin plays a vital role in over 400 enzymes which catalyze biochemical reactions in your body. One study suggests that a diet rich in niacin could protect your skin against ultraviolet (UV) radiation.
A severe niacin deficiency called pellagra is ultimately a lethal disease. While it was common in the early 20th century, pellagra is uncommon in industrialized populations where most processed foods are fortified with niacin. Currently, pellagra is limited to people living in poverty whose diets are low in niacin and protein.
