Most people get enough niacin -- 14 mg to 16 mg a day -- from the foods they eat. Good sources include beef, salmon and peanuts. Foods that contain tryptophan, an amino acid that converts to niacin in your body, include dairy products and eggs. Niacin obtained from your diet can improve liver function, but niacin taken in large doses to lower cholesterol may cause liver damage.
Niacin Uses
Niacin, also called vitamin B3, helps you convert the food in your diet to energy for your body. It also helps you metabolize fats and proteins. Niacin helps improve the health of your skin, eyes and hair as well as make sex- and stress-related hormones. Niacin has been prescribed since the 1950s and proves effective in improving three types of lipids in your bloodstream: low-density lipoprotein, high-density lipoprotein and triglycerides. But researchers at the National Institutes of Health recently halted a niacin study because early results showed the vitamin yielded greater risks than benefits.
Niacin and Liver
Doses for niacin to improve cholesterol range from less than 100 mg a day to 2,000 mg daily. Doses higher than 100 mg a day increase the risk of liver damage. Taking niacin periods for long periods of time also increases liver damage risk. Slow-release niacin tablets, sometimes called no-flush niacin, help prevent one the most common side effects of taking niacin -- burning, tingling and reddening of your face and chest. But taking slow-release niacin tablets increases the danger of liver damage. If you take more than 100 mg of niacin a day, get your liver checked regularly.
Niacin Benefits
Drugs that help lower LDL cholesterol and triglycerides generally don't work as well to elevate healthy HDL cholesterol. Niacin works better than man-made drugs to improve HDL, so niacin is sometimes prescribed in combination with other cholesterol-lowering medications such as statins. Niacin may also reduce hardening of the arteries and improve joint mobility in persons with osteoarthritis. Limited studies suggest including niacin in your diet may help protect you against Alzheimer's disease, and niacin in topical form may help treat acne and other skin conditions.
Niacin Risks
Taking niacin in large quantities carries risks in addition to liver damage. Niacin may also cause stomach ulcers. More seriously, niacin may increase your risk of suffering a stroke, according to a study funded -- and stopped prematurely -- by the National Institutes of Health. Some of the participants in the study took both statins and 2,500 mg of niacin daily. Some participants took only statins and a placebo. Participants who took the combination therapy enjoyed greater reductions in their triglycerides and greater elevations in their HDL cholesterol than persons who took only statins. But trial participants who took niacin suffered more strokes than persons who took placebos.
