Antioxidant Vitamins May Increase Mortality

The largest analysis of data on antioxidant vitamins ever conducted has shown that beta-carotene, vitamin A, and vitamin E probably increase mortality. Two other antioxidant substances — vitamin C and selenium — had no effect on mortality.
The meta-analysis of 68 randomized trials with a total of 232,606 participants, published in the February 28 issue of JAMA, was conducted by a group led by Goran Bjelakovic, MD, of the Copenhagen University Hospital in Denmark.
Coauthor, Christian Gluud, MD, of the Copenhagen University Hospital in Denmark, commented to heartwire: "This is the most comprehensive collection of data on anti-oxidant vitamins ever conducted, and we have shown that on the whole that these agents have no benefit. Indeed, vitamin A, vitamin E and beta-carotene are associated with an increase in mortality at the doses studied. Vitamin A and beta-carotene seem to have a dose-related effect, with mortality increasing as doses increase, whereas vitamin E does not appear to have a dose-related effect, with all doses associated with increased mortality."
Jury Still Out on Vitamin C and Selenium
Dr. Gluud added that the jury is still out on vitamin C and selenium. "Vitamin C does not appear to be detrimental but it is not beneficial either, and all the trials of selenium together suggest a small benefit, but when only the well conducted trials are included, there appears to be neither benefit nor harm." "Our data show that anti-oxidant vitamins should not be taken in an effort to prevent illness. People should instead eat a balanced diet and take regular exercise," he said.
In the JAMA article, the authors note that many people are taking antioxidant supplements in the belief that they improve health and prevent diseases. Many primary or secondary prevention trials of antioxidant supplements have been conducted to prevent several diseases — mainly cardiovascular disease and cancer — but results have generally not been positive, with some trials showing increases in mortality.

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