Pellagra is a disease that affects digestive tract, skin and nerves. Another major cause of pellagra is digestion problems in the body, due to which the niacin is not absorbed in the body. Niacin is also known as nicotine acid.
Sweet potatoes are also known as yams. The sweet potato is a monocotyledons plant that belongs to the morning glory family, Convolvulaceae. Its large, stuffy, sweet-tasting, tuberous roots are a root vegetable.