Vitamin B3 is known as niacin, nicotinic acid and nicotinamide. It is water soluble, it is not stored in the body and needs to be replenished frequently. Niacin is required for the metabolism of food, to maintain healthy skin, nerves and gastrointestinal tract. Vitamin B3 is found in foods that are rich in protein. If you are non-vegetarian, you can include eggs, meat and fish in your diet. Others can have legumes, peanuts, peas, low fat milk and cheese, soybeans and nuts. Other sources are wheat germ, cereals, mushrooms, green vegetables and yeast to list a few. Deficiency of Vitamin B can lead to pellagra.