Niacin, also known as vitamin B-3, is used mainly by the body as an enzyme to help release food from energy. Tryptophan, an amino acid present in many protein foods, can be converted to niacin in the body. That is why the recommended dietary allowance is stated in niacin equivalents, because it can be garnished from two different sources. One niacin equivalent is equal to 1 milligram of niacin or 60 mg of tryptophan. The RDA for niacin for is 16 milligrams for men and 14 milligrams for women.
Beef, Game, and Lamb
In general, foods rich in protein are also rich in tryptophan, which can satisfy some of your requirements for niacin. Niacin-rich meats include beef liver, which provides 14.4 milligrams for a 3.5-ounce cooked portion, or nearly 100 percent of the RDA of 16 milligrams. The same amount of ground beef, cooked, provides 5.3 milligrams, or 33 percent of the RDA, while 4-ounces of cooked lean beef tenderloin provides 4.4 milligrams, or 27.5 percent of the RDA. A 4-ounce cooked portion of either venison or lamb provides about 7.6 milligrams of niacin each, or about 50 percent of the RDA.
Poultry and Seafood
White meat chicken offers 13.4 milligrams for a 3.5-ounce portion, cooked, or over 80 percent of the RDA. A 4-ounce portion of roasted turkey breast provides 7.2 milligrams of niacin, or 45 percent of the RDA. Seafood is an excellent source of niacin. All of the following provide 50 to 85 percent of the RDA in the portions specified. Yellowfin tuna provides a whopping 13.5 milligrams in a 4-ounce cooked portion. A 3-ounce serving of tuna from canned, packed in water, offers 11.8 milligrams of niacin while a 3.5-ounce portion of cooked salmon or halibut both offer 8.0 milligrams.
Legumes, Nuts and Grains
Peanuts provide 10.5 milligrams for a 1/2-cup serving, or 2/3 of the RDA. Thus, peanut butter is also a great food source of niacin, providing 4.4 milligrams, or 27.5 percent of the RDA, in 2 tablespoons. Lentils, cooked, and almonds provide some niacin, about 1.4 milligrams each, or 9 percent of the RDA, for a 1/2-cup serving. Ready-to-eat cereals can be good food sources of niacin. A 1-cup serving of Cheerios provides 5 milligrams, or 32 percent of the RDA. A plain 2.5-ounce bagel, 10-inch flour tortilla, cup of cooked pasta or 1/2-cup of cooked barley each offer 3.3, 2.6, 2.3, and 1.6 milligrams of niacin, or 21, 16, 14.4, and 10 percent of the RDA for niacin, respectively.
Fruits and Vegetables
Certain fruits and vegetables are good food sources of niacin. A 1/2-cup serving of raw mushrooms provides 1.7 milligrams of niacin, or 11 percent of the RDA. Mangoes are the only fruit considered to be a good food source of niacin. One medium fruit offers 1.5 milligrams of niacin. A 1-cup cooked serving of asparagus offers 1.9 milligrams of niacin and a half of a sweet potato, cooked, offers 1.2 milligrams of niacin, or 7.5 and 9 percent of the RDA, respectively.