Some Antioxidant Supplements May Raise Death Risk

But critics say the review of the data has serious flaws.

By Ed Edelson
HealthDay Reporter
Tuesday, February 27, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

TUESDAY, Feb. 27 (HealthDay News) -- For years, the word "antioxidant" has been synonymous with disease-fighting goodness for most health-conscious Americans, but too much of the compounds just might be bad for you.

A controversial new review of data from 68 studies concludes that some of the antioxidant supplements that people take to prevent or treat disease might actually increase their risk of death.

The study, published in the Feb. 28 issue of the Journal of the American Medical Association, drew quick criticism from one independent expert.

"One of the major premises of doing such a meta-analysis is that the studies should be comparable," said Jeffrey Blumberg, director of the Antioxidants Research Laboratory at Tufts University in Boston. "Here, they looked at primary prevention, treatment, old people, young people, smokers, nonsmokers. Only when they used their own criteria of what was good and what was bad were they able to show an increase in all-cause mortality."

The study, led by Dr. Goran Bjelakovic of the Center for Clinical Intervention Research at Copenhagen University Hospital, Denmark, covered trials encompassing more than 232,600 participants.

It found no overall increase in death rates when all the trials were considered. But when the trials were divided into classes using the researchers' own criteria, they found an increased risk of mortality associated with beta carotene, vitamin A and vitamin E supplements. No increased risk was found for two other antioxidants, vitamin C and selenium.

"Our findings contradict the findings of observational studies claiming that antioxidants improve health," the researchers wrote. They hypothesized that eliminating free radicals might interfere with a natural defense mechanism and possibly increase the risk of death.

A representative of the supplements industry was not impressed with the study, however.

The mortality risk finding was unwarranted and the study badly flawed, said Andrew Shao, vice president for science and regulatory affairs at the Council for Responsible Nutrition, a trade association representing the dietary supplement industry.