A major international study found that niacin does not reduce the risk of heart attack or stroke in people with high cholesterol, but it does boost the risk of death.
Therefore, most people should not take the widely used supplement, also known as vitamin B3, according to an editorial in the New England Journal of Medicine that was published along with the results of the randomised trial.
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Niacin has been gaining in popularity over the past 50 years and works mainly by raising "good" HDL (high-density lipoprotein) cholesterol levels.
However, a four-year study on people aged 50-80 with high cholesterol found no benefit toward cutting the rate of heart attack or stroke.
The study included 25,673 people, all of whom were already taking statins to reduce their cholesterol. In addition, some were taking extended-release niacin and laropiprant (a drug that reduces face flushing caused by high doses of niacin). Others were randomly assigned to a placebo.
Research sites included Britain, China and Scandinavia.
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Niacin "was associated with an increased trend toward death" the findings said, adding that it was also associated with "significant increases in serious side effects: liver problems, excess infections, excess bleeding, gout, loss of control of blood sugar for diabetics and the development of diabetes in people who didn't have it when the study began."
Donald Lloyd-Jones, chair of preventive medicine at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital, said the nine percent increased risk of death among niacin users – which researchers found was borderline statistically significant – means that any benefits are overshadowed.
"There might be one excess death for every 200 people we put on niacin," said Lloyd-Jones, who wrote the editorial in the journal.
"With that kind of signal, this is an unacceptable therapy for the vast majority of patients."
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Another study on niacin, involving more than 3,400 patients, found it increased the risk of infection while, however, offering protection against cardiovascular problems, the New England Journal of Medicine reported.
"Niacin must be considered to have an unacceptable toxicity profile for the majority of patients, and it should not be used routinely," wrote Lloyd-Jones.
Instead, statin therapy should remain the leading drug-based approach to cutting cholesterol, and niacin should be reserved for high-risk patients who are unable to tolerate statins, he said.
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Image: Cholesterol plaque in artery from Shutterstock