Some animal products that are good sources of niacin, also known as vitamin B3, are fish, chicken, pork, liver and beef. Plant sources of niacin are peanuts, mushrooms, green peas, sunflower seeds and avocados.
Niacin is a water-soluble vitamin that is passed through urine, which means people need a steady supply of it in their diet. Niacin plays an important role in lowering cholesterol, processing fat and regulating blood glucose levels in the body. When a diet is deficient in niacin, pellagra can occur. Symptoms of pellagra include inflammation of the skin, digestive problems and cognitive impairment. Male adults should consume 16 milligrams of niacin per day and women should take 14 milligrams per day.