Junkfood Science: Take your vitamins?

November 21, 2006

Take your vitamins?

Last week, while every media outlet imaginable was telling us about a study that supposedly found another danger in red meat — (stay tuned for Wednesday’s special blog exclusive!) — a momentous study remained under the radar.

The results of the long-awaited Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS) were reported at last week’s American Heart Association Scientific Sessions. This was a randomized, double-blind, placebo-controlled clinical trial — as good as it gets.

This clinical trial is a subset of the Women's Antioxidant Cardiovascular Study (WACS) which began in May 1993 and ran through February of this year. It was carefully designed to test whether antioxidant vitamins, vitamin E, vitamin C, beta-carotene; and a folic acid, vitamin B6 and B12 combination; could prevent heart disease events among 8,171 women at high risk (with preexisting cardiovascular disease or three or more risk factors). The trial also examined whether these micronutrients are useful in preventing vision problems and cognitive decline.

The study design and randomization were evaluated two years ago and found to be sound and the scientists felt reasurred that the results minimized confounding factors and would provide unbiased estimates of the balance of benefits and risks, and that there is little biological basis for supposing that any benefits found will be any different for other women.

It’s findings? [drumroll, please....]

There was NO benefit of folic acid or vitamins B6 or B12 in the prevention of heart problems. In the antioxidant part of the study, they also found no cardiovascular benefits from the antioxidants vitamin C, E or beta-carotene. There was no difference among the treatment and placebo-control groups in any of the primary end measures: heart attacks, strokes, revascularization procedures or cardiovascular death.

An early hypothesis that these vitamins lead to a reduction in homocysteine and subsequently reduce cardiovascular events has already been resoundly disproven in a series of randomized clinical trials, such as HOPE-2, NORVIT, and VISP. Likewise, this study found that while the treatment group had 18% lower homocysteine levels, it did not translate to any cardiovascular benefit. Homocysteine as a cardiac risk factor has been laid to rest.

Dr. Christine M. Albert of Brigham and Women's Hospital in Boston and her colleagues were also able to examine the effect of folic-acid fortification of foods because baseline blood samples had been taken from the women before the U.S. fortification of foods. Fortification didn’t appear to account for the null findings in their study. The doctors did voice a precaution for women of childbearing years, however, noting that folic acid supplementation has been associated with reducing birth defects of the brain and spinal cord in newborns.

This study highlights the importance of clinical studies that actually test the hypotheses gleaned from observational data. But its findings really weren’t a surprise at all. This study joins a body of similar clinical evidence (which also received little media notice) that has demonstrated so conclusively that taking vitamins doesn’t prevent heart problems, the leading cause of death, that major healthcare guidelines may actually change this time.

But please don’t worry that taking a multi-vitamin in RDA amounts will hurt you, because they didn’t find anything to support that fear, either.

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