MedlinePlus Medical Encyclopedia: Niacin

Skip navigation


Medical Encyclopedia
Other encyclopedia topics:	A-Ag Ah-Ap Aq-Az B-Bk Bl-Bz C-Cg Ch-Co Cp-Cz D-Di Dj-Dz E-Ep Eq-Ez F G H-Hf Hg-Hz I-In Io-Iz J K L-Ln Lo-Lz M-Mf Mg-Mz N O P-Pl Pm-Pz Q R S-Sh Si-Sp Sq-Sz T-Tn To-Tz U V W X Y Z 0-9

Niacin

Contents of this page:
Illustrations Alternative names Definition Function	Food Sources Side Effects Recommendations

Illustrations

Vitamin B3 benefit

Vitamin B3 deficit

Vitamin B3 source

Alternative names Return to top

Diet - niacin; Nicotinic acid

Definition Return to top

Niacin is a water-soluble vitamin necessary for many aspects of health, growth, and reproduction. It is part of the vitamin B complex.

Function Return to top

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 Return to top

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 Return to top

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 Return to top

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

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.

Specific recommendations for each vitamin depend on age, gender, and other factors (such as pregnancy). The U.S. Department of Agriculture has a PDF file that lists these recommendations.

Update Date: 1/18/2003

Updated by: Steven Angelo, M.D., Assistant Professor of Medicine, Yale School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.