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Death by vitamins
Thursday, 1 March 2007
Agençe France-Presse
Certain vitamins have no health benefits and actually increase the risk of death, say Danish researchers.
WASHINGTON: Taking vitamins A, E and other antioxidant supplements may increase the risk of death and carries no clear health benefits as claimed by vitamin makers.
In a blow to the healthy image often associated with dietary supplements, a wide-ranging Danish-led review of 47 clinical trials, involving 180,938 patients, concluded that vitamins A, E and beta carotene are in fact linked to a rise of five per cent in the risk of mortality.
The findings, based on electronic databases and bibliographies, were published in today's edition of the Journal of the American Medical Association.
"Beta carotene, vitamin A, and vitamin E given singly or combined with other antioxidant supplements significantly increase mortality," wrote the authors, led by Goran Bjelakovic of the Centre for Clinical Intervention Research at Copenhagen University Hospital. "Our findings contradict the findings of observational studies, claiming that antioxodiants improve health."
The study also found that there was no evidence vitamin C may increase longevity and added: "We lack evidence to refute a potential negative effect of vitamin C on survival."
With an estimated 10 to 20 per cent of the adult population in North America and Europe - 80 to 160 million people - taking antioxidant supplements, "the public health consequences may be substantial," the authors wrote.
The U.S. market for antioxidant supplements was estimated at more than five billion dollars (A$6.3 billion) in 2006. The authors deplored the intense marketing that touts the alleged health benefits of antioxidant supplements and offered possible explanations as to why the products can have a negative effect.
"By eliminating free radicals from our [body], we interfere with some essential defensive mechanisms," read the study. The antioxidant supplements are synthetic and not subject to the same toxicity studies as other pharmaceutical agents.
"Better understanding of mechanisms and actions of antioxidants in relation to a potential disease is needed," the researchers concluded.
The makers of vitamins and other dietary supplements are not required to register their products with the U.S. government's Food and Drug Administration that regulates medicine and food products, but the FDA can order the withdrawal of products on the market that are found to pose a risk to public health.