Food sources
In general, meat, poultry, and fish are better sources of niacin than plant products, as emphasized, showing average servings. The use of meat drippings is recommended, because niacin in easily dissolved out of foods in cooking. Whole grain and enriched products also make a contribution. A bound form of niacin, that is, niacytin, in wheat, corn, and ryebran is practically unavailable to humans,unless released by the method of preparation, for example, lime-treated corn. Fruits and vegetables (other than mushrooms and legumes) are insignificant sources of niacin. Milk and eggs are poor sources of preformed niacin but good sources of its precursor, tryptophan. The average American diet is estimated to contain 8 mg to 17 mg niacin and 500 mg to 1000 mg or more of tryptophan, with a total of16 mg to 34 mg of niacin equivalents.
