Health Encyclopedia

Niacin

Definition

Niacin is a type of B vitamin. It is water-soluble, which means it is not stored in the body. Water-soluble vitamins dissolve in water. Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such vitamins in your diet.

Alternative Names

Diet - niacin; Nicotinic acid; Vitamin B3

Function

Niacin assists in the functioning of the digestive system, skin, and nerves. It is also important for the conversion of food to energy.

Food Sources

Niacin (also known as vitamin B3) is found in dairy products, poultry, fish, lean meats, nuts, and eggs. Legumes and enriched breads and cereals also supply some niacin.

Side Effects

A deficiency of niacin causes pellagra. The symptoms include inflamed skin, digestive problems, and mental impairment.

Large doses of niacin can cause liver damage, peptic ulcers, and skin rashes. Even normal doses can be associated with skin flushing. It can be prescribed as a treatment for elevated total cholesterol and other types of lipid disorders, but it should only be used with medical supervision due to its potential for severe side effects.

Recommendations

Recommended daily allowances (RDAs) are defined as the levels of intake of essential nutrients that the Food and Nutrition Board at the Institute of Medicine has found to be adequate to meet the known nutrient needs of most healthy persons.

Specific recommendations for each vitamin depend on age, gender, and other factors (such as pregnancy). The general recommended intakes for niacin are listed below:

Infants

0-6 months: 2 milligrams per day (mg/d)
7-12 months: 4 mg/d

Children

1-3 years: 6 mg/d
4-8 years: 8 mg/d
9-13 years: 12 mg/d

Adolescents and Adults

Age 14 and up: 14 mg/d
Pregnant women: 18 mg/d
Breastfeeding women: 17 mg/d

The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide pyramid.

Review Date:1/2/2007
Reviewed By:William McGee, M.D., M.H.A., Assistant Professor of Medicine and Surgery, Tufts University School of Medicine, Boston, MA, and Chairman, Nutrition Committee, Baystate Medical Center, Springfield, MA. Review provided by VeriMed Healthcare Network.

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