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Image for niacin Niacin, also known as vitamin B3, is a water-soluble vitamin. Water-soluble vitamins are stored in the body in very limited amounts and are excreted through the urine. Therefore, it is a good idea to have them in your daily diet. In addition to getting niacin from dietary sources, the body can synthesize a form of niacin from the amino acid tryptophan.


Niacin’s functions include:

Recommended Intake:

Age Group (in years)Recommended Dietary Allowance
1-36 mg6 mg
4-88 mg8 mg
9-1312 mg12 mg
14 and older16 mg14 mg
Pregnancyn/a18 mg
Lactatingn/a17 mg

Niacin Deficiency

A niacin deficiency is called pellagra. The most common symptoms affect the skin, the digestive system, and the nervous system. Symptoms of niacin deficiency include:

If left untreated, pellagra can lead to death.

Niacin Toxicity

For adults, the tolerable upper intake level (UL) for niacin from dietary sources and supplements combined is 35 mg. Niacin toxicity does not seem to occur when its only source is foods which have not been fortified with niacin. Symptoms of niacin toxicity have been reported in people using niacin supplements.

Symptoms of toxicity include:

Major Food Sources

FoodServing Size Niacin Content
Breakfast cereal (unfortified)1 cup5-7 (check Nutrition Facts label)
Chicken, roasted without skin3 ounces7.3
Tuna, packed in water3 ounces11.3
Salmon, broiled3 ounces8.5
Turkey, roasted white meat3 ounces10
Avocado5 ounces2.9
Peanuts, dry roasted1 ounce3.8
Beef3 ounces5.8
Pasta, enriched, boiled1 cup2.4
Lentils, cooked1 cup2.1
Lima beans, cooked1 cup1.8
Bread, whole wheat1 slice1.3

Health Implications

Populations at Risk for Niacin Deficiency

The following populations may be at risk for niacin deficiency or have an increased need for niacin and may require a supplement:

High Cholesterol

Several well-designed clinical studies have shown that niacin can lower LDL-cholesterol and triglycerides (high blood levels of LDL-cholesterol and triglycerides are considered unhealthy); studies have also shown that niacin can raise HDL-cholesterol (higher blood levels of HDL-cholesterol are considered healthy). However, the studies that found positive results used pharmacologic doses of niacin. These doses are much larger than the current recommended dietary allowances (RDA) and should only be used under the supervision of a qualified healthcare provider.

Tips For Increasing Your Niacin Intake:

To help increase your intake of niacin:


American Society for Nutrition

Eat Right—American Academy of Nutrition and Dietetics


Dietitians of Canada

Health Canada


Avocado Nutrition Facts and Label. Avocado Central website. Available at: Accessed May 5, 2016.

Niacin. Oregon State University Linus Pauling Institute's Micronutrient Information Center website. Available at: Accessed May 5, 2016.

Last reviewed May 2016 by Michael Woods, MD  Last Updated: 6/5/2014