CRN Criticizes Design of Study on B Vitamins and Cardiovascular Disease

A study published in the June 23/30 issue of the Journal of the American Medical Association (JAMA) supports conclusions that B vitamins and folic acid lower homocysteine levels, but failed to demonstrate that lowering homocysteine levels in persons who already have cardiovascular disease (CVD) will provide protection against a future heart attack or stroke.

According to Duffy MacKay, N.D., vice president, scientific & regulatory affairs, CRN, “The concern with this study is that it focused on treating individuals who have already had a heart attack. It didn’t answer the question of whether a B vitamin – taken over time and in combination with other healthy lifestyle habits – could have helped prevent cardiovascular disease before it occurred at all. We may need to re-evaluate expectations when designing studies on nutrients used to treat serious chronic disease because it is unrealistic to expect a vitamin to undo a lifetime of unhealthy behaviors.”

The Study of the Effectiveness of Additional Reductions in Cholesterol and Homocysteine (SEARCH) demonstrated that vitamin B supplementation lowered blood homocysteine levels, a biomarker for which lower levels are assumed to be associated with lower risk of heart disease and stroke. Researchers found that even with the lowered homocysteine levels, study participants overall did not see a reduced reduction in the risk of a second coronary event or stroke. The study’s authors noted that a previous meta-analysis of prospective studies offered evidence that lower homocysteine levels resulted in 11 percent lower risk of coronary heart disease and 19 percent lower risk of stroke.

“We should remember that scientific knowledge grows in increments, and not to sacrifice the potential positive relationship between B vitamins and cardiovascular health given the results of one study. The researchers may have gotten too far ahead of themselves by expecting to see successful disease treatment without first understanding if the positive relationship between homocysteine levels and cardiovascular disease is causal,” said Dr. MacKay. “Because we know that vitamin B supplementation lowers homocysteine levels in the blood, we must now shift our focus to determine if homocysteine is a valid biomarker. In addition we should continue to explore how lowering homocysteine levels as a preventative measure will protect against the development of heart disease.”

Researchers also found that seven years of treatment with 2 mg of folic acid and 1 mg of vitamin B12 daily showed no evidence of adverse effects on cancer at any site, including colorectal, prostate, or lung.

Dr. MacKay reminded consumers that vitamins and other supplements are not a cure or treatment for any disease, but when incorporated into a healthy lifestyle may help to reduce the risk of several health-related issues and can play an important role in maintaining overall health and wellness.

The Council for Responsible Nutrition (CRN), founded in 1973, is a Washington, D.C.-based trade association representing dietary supplement manufacturers and ingredient suppliers. In addition to complying with a host of federal and state regulations governing dietary supplements in the areas of manufacturing, marketing, quality control and safety, our 70+ manufacturer and supplier members also agree to adhere to additional voluntary guidelines as well as CRN’s Code of Ethics. Visit

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