Vitamin B3 (niacin) is one of the eight B-complex water-soluble vitamins that helps keep the nervous system, digestive system and skin healthy. It helps the body use fat, protein and carbohydrates from foods to make energy.
Most people get an adequate supply of this vitamin from the foods that they eat. Foods rich in B3 include yeast, meat, fish, milk, eggs, green vegetables and cereal grains (1).
Supplementation has long been linked to improving cholesterol and triglyceride levels, and researchers theorize that supplementation may also benefit cognition and longevity.
One of the main concerning side effects is that prolonged supplementation increases insulin resistance.
Vitamin B3 may help improve cholesterol and triglyceride levels. There have been mixed results and debates on whether or not niacin can have a positive effect on lipid levels and overall cardiovascular health. Niacin has been used for primary and secondary coronary heart disease prevention for over 40 years. Until recently, clinical trials incorporating niacin as part of an intervention strategy consistently demonstrated its benefits.
In recent years, however, two large clinical trials failed to replicate the findings of earlier studies. As a result, researchers concluded that while niacin did provide additive effects on biomarkers of cardiovascular health (lowered LDL or “bad” cholesterol and triglycerides and raised HDL or “good” cholesterol), when added to statin therapy, overall, it did not reduce the risk of ischemic stroke or myocardial infarction any more than statins alone (2).
Some researchers explain that differences in how earlier and recent trials were carried out may explain the discrepancy in results. Differences include niacin formulation, dosing, timing and subject dyslipidemia types (3).
More research is needed to better understand niacin’s role in improving cardiovascular health.
Vitamin B3 may have an anti-inflammatory effect. In a recent study, researchers set out to evaluate the effect of niacin on an experimental colitis model and to shed some light on the ability of niacin to modulate angiogenesis (the development of new blood vessels) which plays a crucial role of in the development of inflammatory bowel disease (inflammation can promote angiogenesis and new blood vessels may enhance tissue inflammation).
At the end of the study, niacin was shown to be effective in reducing the severity of colitis by improving angiogenesis and inflammatory changes. (4).
Niacin may help treat symptoms of schizophrenia. There has been some evidence suggesting that increasing niacin intake can be useful for the treatment of schizophrenia. In an effort to further shed light on niacin’s role, authors of a study published in the European Review for Medical and Pharmacological Sciences, presented a short description of their case report.
They found rapid improvement in schizophrenic psychotic symptoms subsequent to administration of niacin as an augmentation therapy. The authors suggest that niacin deficiency is a contributory factor in schizophrenia development in some patients and symptom improvement in these patients will benefit from niacin augmentation, especially in some particular psychotic features.
They encourage further studies (5).
Niacin may provide skin protection. Nonmelanoma skin cancers, such as basal-cell carcinoma and squamous-cell carcinoma, are common cancers that are caused primarily by ultraviolet (UV) radiation. Nicotinamide (a form of vitamin B3) has been shown to have protective effects against damage caused by UV radiation.
In one study, 386 participants who had experienced at least two nonmelanoma skin cancers in the previous 5 years were randomly assigned to receive 500 mg of nicotinamide twice daily or placebo for 12 months.
At 12 months, the rate of new nonmelanoma skin cancers was lower by 23 percent in the treatment group than in the placebo group. Similar differences were found between the treatment group and the placebo group with respect to new basal-cell carcinomas (20 percent lower rate) and new squamous-cell carcinomas (30 percent lower rate) 6.
In addition, the number of actinic keratoses (rough, scaly patches on the skin that develops from years of exposure to the sun) was 11 percent lower in the nicotinamide group.
Vitamin B3 may improve symptoms of osteoarthritis. Osteoarthritis is one of the most common forms of arthritis that is caused when the protective cartilage on the ends of the bones wears down over time. Pain, stiffness and swelling are the main symptoms (7).
Anti-inflammatory medications are the usual treatment to help relieve symptoms. In a pilot study, 72 patients with osteoarthritis were randomized for treatment with nicotinamide or an identical placebo for 12 weeks.
Supplementation improved joint flexibility, reduced inflammation and allowed for reduction in standard anti-inflammatory medications when compared to placebo (8).
When taken orally in appropriate amounts, niacin appears to be safe.
High doses of niacin available via prescription can cause severe skin flushing, dizziness, rapid heartbeat, itching, nausea and vomiting, abdominal pain, diarrhea, gout and liver damage.
Serious side effects are most likely when taking 2,000 to 6,000 mg of niacin a day (9).
Large doses of niacin (3-9 grams) can interfere with blood glucose control (10).
Due to concerning side effects such as prolonged supplementation increasing insulin resistance, and mixed results when it comes to whether or not supplementation improves cardiovascular health, it is best to consult with a physician prior to use.
Vitamin B3 (niacin) is one of the eight B-complex water-soluble vitamins that helps the body use fat, protein and carbohydrates from foods to make energy. It plays a role in keeping the nervous system, digestive system and skin healthy.
The addition of niacin therapy to statins helps improve cholesterol levels (by raising “good” HDL and lowering “bad” LDL). Although it has been used as coronary heart disease prevention for over 40 years, recent studies find that it has no effect on actually reducing the risk of cardiovascular incidents.
Further studies are needed to understand niacin’s role in heart health.
Early research also shows niacin’s anti-inflammatory properties and its ability to help treat symptoms of schizophrenia, osteoarthritis and protect the skin from common forms of skin cancer caused by exposure to UV light.
Vitamin B3 appears to be safe when taken as directed. High doses have been linked to several side effects, namely skin flushing, dizziness, rapid heartbeat, nausea and vomiting, abdominal pain, diarrhea, gout and liver damage.
There is also a concern that prolonged supplementation increases insulin resistance.