Vitamin B3, or niacin, is an essential vitamin required for processing fat in the body, lowering cholesterol levels, and regulating blood sugar levels.
A deficiency of niacin leads to pellagra, a condition characterized by diarrhea, dermatitis, dementia, inflammation of the mouth, amnesia, delirium, and if left untreated, death. Even a slight deficiency of niacin can lead to irritability, poor concentration, anxiety, fatigue, restlessness, apathy, and depression.
Niacin is a water-soluble vitamin that is well regulated by the body, thus overdose is rare, and only occurs when niacin is taken in the form of supplements. An overdose of niacin is seen in the form of skin rashes (flush), dry skin, and various digestive maladies. A long-term overdose can lead to liver damage, elevated blood sugar levels, and type II diabetes, as well as increased risk of birth defects.
High niacin foods include fish, chicken, turkey, pork, beef, mushrooms, brown rice, peanuts, avocados, green peas, and avocados. The current daily value (% DV) for niacin is 16mg.
Protect Against Heart Disease - Niacin is prescribed pharmacologically to lower LDL fats and triglycerides by preventing the breakdown of fats into these individual components. Niacin consumed at such high levels can cause rashes, headaches, nausea, and diarrhea. Consult your doctor before taking niacin supplements in high doses.2,3
Regulation of Blood Sugar and Insulin Dependence (*Controversial) - Studies suggest that vitamin B3 (niacin) can help decrease insulin sensitivity,4 however, other studies find no difference.5 Niacin has also been shown to help alleviate some of the destructive autoimmune reactions of type I diabetes, and further studies are being conducted to asses its effectiveness.5
Reduced Cancer Risk - Studies show that niacin reduces cancer risk via ensuring DNA integrity and maintenance, and through proper regulation of the tumor suppressor gene: p53.6-8
Slow the progression of AIDS - An observational study has reported slowing the progression of AIDS and increasing survival with high doses of niacin.9
People at Risk of a Niacin (Vitamin B3) Deficiency
People with HIV/AIDS - The body's immune system creates a specific cytokine, interferon gamma, which breaks down tryptophan, a precursor of niacin. Studies show that HIV patients who take increased levels of niacin slow the progression of AIDS.9-11
People who eat high amounts of refined foods - Bran, which is high in vitamin b3, is typically removed during any refining process. Anyone who eats high amounts of white bread, white rice, corn syrup, or other refined products will not receive adequate amounts of niacin. Even though most of these foods are now fortified, it is still best to eat unrefined food products.
USDA National Nutrient Database for Standard Reference, Release 28.
"Guidelines for Niacin Therapy For the Treatment of Elevated Lipoprotein a (Lpa)". Rush Hemophilia & Thrombophilia Center. August 15, 2002, Revised July 27, 2005. Retrieved 20 November 2009. "facial flushing is a common side effect of niacin therapy that usually subsides after several weeks of consistent niacin use"
Katzung, Bertram G. (2006). Basic and clinical pharmacology. New York: McGraw-Hill Medical Publishing Division. ISBN 0071451536.
Greenbaum CJ, Kahn SE, Palmer JP. Nicotinamide's effects on glucose metabolism in subjects at risk for IDDM. Diabetes. 1996;45(11):1631-1634.
Lampeter EF, Klinghammer A, Scherbaum WA, et al. The Deutsche Nicotinamide Intervention Study: an attempt to prevent type 1 diabetes. DENIS Group. Diabetes. 1998;47(6):980-984.
Hageman GJ, Stierum RH. Niacin, poly(ADP-ribose) polymerase-1 and genomic stability. Mutat Res. 2001;475(1-2):45-56.
Jacobson EL, Shieh WM, Huang AC. Mapping the role of NAD metabolism in prevention and treatment of carcinogenesis. Mol Cell Biochem. 1999;193(1-2):69-74.
Weitberg AB. Effect of nicotinic acid supplementation in vivo on oxygen radical-induced genetic damage in human lymphocytes. Mutat Res. 1989;216(4):197-201.
Tang AM, Graham NM, Saah AJ. Effects of micronutrient intake on survival in human immunodeficiency virus type 1 infection. Am J Epidemiol. 1996;143(12):1244-1256.
Brown RR, Ozaki Y, Datta SP, Borden EC, Sondel PM, Malone DG. Implications of interferon-induced tryptophan catabolism in cancer, auto-immune diseases and AIDS. Adv Exp Med Biol. 1991;294:425-435.
Murray MF, Langan M, MacGregor RR. Increased plasma tryptophan in HIV-infected patients treated with pharmacologic doses of nicotinamide. Nutrition. 2001;17(7-8):654-656.