Any dietary or drug treatment with high doses of micronutrients may override the body's own control mechanisms; therefore, micronutrient therapies may be associated with potential side effects and toxicities. High-dosed micronutrients should not be used without medical supervision..
The Coronary Drug Project (CDP) followed over 8,000 men with a history of heart attack (‘myocardial infarction’) for six years (13). Compared to the placebo group, the group that took 3 g vitamin B3 (nicotinic acid) daily experienced an average 10% reduction in total blood cholesterol, a 26% decrease in triglycerides, a 27% reduction in recurrent non-fatal myocardial infarction, and a 26% reduction in stroke(‘cerebrovascular’ events). A post-trial follow up nine years later revealed a 10% reduction in total deaths with nicotinic acid treatment.
Because of the heart-protective effects of high doses of vitamin B3 (nicotinic acid), potentially related to changes in blood lipid profile (e.g., increase of HDL-cholesterol levels and decrease of LDL), it has been used in combination with other lipid-lowering medications: a randomized controlled trial found that a combination of nicotinic acid (2–3 g/day) and a cholesterol-lowering drug (simvastatin) resulted in greater benefits on serum HDL levels and cardiovascular events, such as heart attack and stroke, than placebo in patients with coronary artery disease and low HDL levels (15). The effects of niacin were dose-dependent (16, 17).
Multiple niacin forms have similar effects on plasma lipids levels while different side effects (41). In a meta-analysis of 30 trials with 4,749 subjects treatment with immediate release, sustained release, or extended release niacin decreased total cholesterol by 10%, decreased triglycerides by 20%, decreased LDL cholesterol by 14%, and increased HDL cholesterol by 16% (41, 42). A small meta-analysis of 5 trials in 432 subjects compared the response to extended release niacin in men and women. The effect of niacin on LDL cholesterol was greater in women than men at all niacin doses (41). Numerous studies have examined the effect of the addition of niacin to statin therapy. Combination therapy typically results in further reductions in atherogenic lipoprotein particles and an increase in HDL cholesterol levels (41, 43).
Although it is a nutrient, at doses required for cholesterol-lowering effects, the use of vitamin B3 (nicotinic acid) should be approached as if it were a drug. Individuals should only undertake cholesterol-lowering therapy with nicotinic acid under the supervision of a qualified health care provider in order to minimize potentially adverse effects and maximize therapeutic benefits.
It has been hypothesized that infection with human immunodeficiency virus (HIV), the virus that causes acquired immmunodeficiency syndrome (AIDS), increases the risk of vitamin B3 (niacin) deficiency (18). An observational study in 281 HIV-positive men found that higher levels of niacin intake were associated with decreased progression rate to AIDS and improved survival (19).
More research is being done and is bringing interesting results on dyslipidemia in HIV/AIDS patients (44) and on the role of B vitamins (including B3) in inflammation among HIV-infected persons (45) .
One preliminary study suggested that nicotinamide may improve arthritis symptoms, including increasing joint mobility and reducing the amount of nonsteroidal anti-inflammatory drugs (NSAIDs) needed (20).
Because neurologic disorders associated with pellagra resemble acute schizophrenia, niacin-based therapy for the condition was investigated during the 1950s-70s (46). The adjunctive use of nutrients like niacin to correct deficiencies associated with neurologic symptoms is called orthomolecular psychiatry (47). Recent scientific advances and new hypothesis on the benefit of nutrient supplementation in the treatment of psychiatric disorders have suggested the re-assessment of orthomolecular medicine by the medical community (48, 49).
Authored by Dr Peter Engel in 2010, reviewed by Giorgio La Fata on 06.06.2017