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Niacin Requirements and Dietary Sources

Vitamin Guide


Updated July 05, 2014

Niacin is a member of the water-soluble family of B-complex vitamins. It's required for normal digestive function, converting the food you eat into energy and for healthy skin and nervous system function.

In addition, niacin is good for blood circulation, and your adrenal glands need it to make certain stress and sex hormones.

Niacin is found in a variety of foods including dairy products, poultry, fish, lean meats, nuts, legumes, eggs and vitamin-fortified foods.

Niacin deficiency is rare in modern Western diets -- it usually occurs as a consequence of alcoholism. Symptoms of a mild niacin deficiency include digestive upset, fatigue, canker sores, vomiting, and depression. Pellagra is caused by a full-blown niacin deficiency. It's symptoms include mental problems, diarrhea, and sores on the skin.

The Institute of Medicine of the National Academies sets the daily dietary reference intakes for vitamins and minerals. The DRI for niacin is determined by age and gender. Women who are pregnant or breastfeeding need the largest amounts.

The DRIs are based on what an average healthy person needs -- if you have any health conditions you should speak with your health care provider about your niacin requirements.

Dietary Reference Intakes


1 to 3 years: 6 milligrams per day
4 to 8 years: 8 milligrams per day
9 to 13 years: 12 milligrams per day
14+ years: 16 milligrams per day


1 to 3 years: 6 milligrams per day
4 to 8 years: 8 milligrams per day
9 to 13 years: 12 milligrams per day
14 + years: 14 milligrams per day
Women who are pregnant: 18 milligrams per day
Women who are breastfeeding: 17 milligrams per day

Niacin is easily obtained from foods so, most people don't need to take supplements to ensure an adequate intake.

However, when taken in large doses, niacin supplements may be used to reduce elevated triglyceride and LDL cholesterol (the bad kind of cholesterol) levels in the blood and to increase levels of HDL cholesterol (the good kind).

Although it's available over the counter,  there are some potential problems with this type of niacin use, so speak to your doctor if you're thinking about taking niacin for cholesterol. Ingesting large amounts of supplemental niacin may result in liver damage, can interact with some types of medications, and might increase glucose levels in people with diabetes.

Taking niacin in large amounts will also cause an uncomfortable reaction called the niacin flushwhich includes burning and itching sensations of the face and joints. It's not dangerous, but it can be frightening the first time it happens.

A form of niacin called inositol hexaniacinate will improve cholesterol levels without causing the niacin flush.

Due to these reactions and safety concerns, the Institute of Medicine established 35 milligrams per day as the upper tolerable intake level for adults.  No matter what form of niacin is used, large doses should only be used under the supervision of a physician.

Also Known As: Nicotinic acid, niacinamide, vitamin B-3


Institute of Medicine of the National Academies. "Dietary Reference Intakes -- Vitamins." Accessed July 5, 2014. http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Vitamins.pdf.

National Institutes of Health Medline Plus. "Niacin." Accessed July 5, 2014. http://www.nlm.nih.gov/MEDLINEPLUS/ency/article/002411.htm.

National Institutes of Health Medline Plus. "Pellagra." Accessed July.5, 2014. http://www.nlm.nih.gov/medlineplus/ency/article/000342.htm.

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