No proof of vitamin C, D, E benefits

Long-term, large-scale studies detect no reduction in heart attacks, stroke, breast cancer

November 12, 2008|By Karen Kaplan | Karen Kaplan,Los Angeles Times

Vitamin supplements - taken by millions of Americans to boost or maintain their health - don't reduce the risk of heart attacks, strokes or breast cancer, according to two large studies published today.

In trial, 14,641 middle-age male physicians took vitamins E and C for an average of eight years but did not see any benefit to their cardiovascular health. The other study tracked 36,282 postmenopausal women for seven years and found that a daily regimen of vitamin D and calcium did not offer any protection against invasive breast cancer.

Almost half of all adults in the U.S. take vitamins daily, but these results should prompt some of them to reconsider doing so, said Howard Sesso, who led the cardiovascular disease study appearing in the Journal of the American Medical Association.

"You don't know whether something is really true until you test it in one of these large-scale, long-term clinical trials," said Sesso, an epidemiologist at Brigham and Women's Hospital in Boston and a professor at Harvard Medical School.

But Dr. David Heber, director of the Center for Human Nutrition of the University of California, Los Angeles, said the studies don't prove vitamins are useless, especially considering that observational studies and experiments with animals have produced mixed results.

The heart study was prompted by basic research showing that antioxidants such as vitamins E and C kept the formation of atheroschlerotic plaque in check and helped prevent tissue damage that causes cardiovascular disease.

Sesso's team tested the effect of 400 international units, or IU, of vitamin E every other day and 500 milligrams of vitamin C daily. Doctors who participated in the study received either both vitamins, one vitamin and one placebo, or two placebos.

Among the 7,315 people who took vitamin E, there were 620 cases of heart attacks, strokes and deaths from heart disease compared to 625 such cases among the 7,326 people who took the dummy pills, according to the study. The only difference the researchers found was a 74 percent increase in hemorrhagic strokes among those who took vitamin E, though Sesso said the strokes were rare in both groups and the finding could have been a fluke.

The results for vitamin C also were underwhelming - 619 major cardiovascular events among the 7,329 doctors who got the vitamin versus 626 events for the 7,312 who got the placebo, according to the study, which was funded by the National Institutes of Health and BASF Corp., a vitamin maker.

The breast cancer study, reported in the Journal of the National Cancer Institute, was developed as part of an effort to determine whether a combined pill of 1,000 milligrams of calcium and 400 IU of vitamin D could help prevent hip fractures.

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