B Vitamins Dont Prevent CV Death: JAMA Study

BERGEN, Norway—Supplementing with B vitamins does not reduce the risk of cardiovascular events or death among patients with coronary artery disease, according to a study published in the Aug. 20 issue of the Journal of the American Medical Association (JAMA) (2008;300(7):795-804). Initial results from the study were presented at the European Society of Cardiology meeting in September 2007.

Marta Ebbing, M.D., and her team at the Haukeland University Hospital enrolled 3,096 patients in two Norwegian hospitals between 1999 and 2006 for the Western Norway B-vitamin Intervention Trial (WENBIT). Patients received folic acid (0.8 mg), vitamin B12 (0.4 mg) and B6 (40 mg); folic acid plus B12; B6 alone; or placebo. Primary outcome was a composite of all-cause death, nonfatal acute myocardial infarction, acute hospitalization for unstable angina pectoris and nonfatal thromboembolic stroke. According to the researchers, the study was ended early after preliminary results of another study suggested intervention with B vitamins could increase risk of cancer.

After just one year, the groups receiving folic acid and B12 had reductions of 30 percent in mean plasma total homocysteine concentration. At the end of the study, there was no preventive effect of intervention on mortality or cardiovascular events; there was a lower incidence of stroke and higher incidence of cancer in the groups receiving folic acid, though the results were not statistically significant.

Andrew Shao, Ph.D., vice president, scientific and regulatory affairs, Council for Responsible Nutrition (CRN), said the results were not particularly surprising. “Recent similar randomized controlled trials have shown that while B vitamins can lower homocysteine levels, they may not ‘cure’ or reduce the risk of subsequent cardiovascular events in patients who already have cardiovascular disease,” he said. “But this study, like other similarly designed studies, still fails to answer the question of whether B vitamin supplementation, over the long-term, can help reduce the risk of cardiovascular disease in a population that is healthy at baseline. It’s important to remember that there is a large body of observational data that suggests that higher B vitamin intake and lower homocysteine levels are both associated with lower CVD risk, which is consistent with how vitamins are intended to be used—as a preventive measure, rather than as a ‘treatment’ to already existing disease.”

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