A review has found that antioxidant supplements such as vitamin E could in fact increase the rate of mortality.

A review of 67 studies on antioxidant supplements has found that they might in fact increase the rate of mortality rather than prolong life expectancy.

Scientists at the Copenhagen University Hospital in Denmark conducted a Cochrane Systematic Review looking at trials involving 230,000 people to see whether so-called antioxidant vitamins prolonged life expectancy. They found, however, that the data failed to support this idea.

Antioxidants are promoted as helping to protect the body from free-radicals, highly reactive molecules capable of causing damage in the brain and other tissues. As well as vitamins A, C and E, they include zinc, ginkgo biloba, grape seed extract and green tea extract.

Goran Bjelakovic, a visiting researcher at the Copenhagen Trial Unit, said: “We could find no evidence to support taking antioxidant supplements to reduce the risk of dying earlier in healthy people or patients with various diseases.

“The findings of our review show that if anything, people in trial groups given the antioxidants beta-carotene, vitamin A, and vitamin E showed increased rates of mortality. There was no indication that vitamin C and selenium may have positive or negative effects. So regarding these antioxidants we need more data from randomised trials.”

The review stated that it did not assess antioxidant supplements for treatment of specific diseases (tertiary prevention), antioxidant supplement for patients with demonstrated specific needs of antioxidants, or the effects of antioxidants contained in fruits or vegetables.

The paper appears in a recent issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organisation that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

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Reference: Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database of Systematic Reviews 2008, Issue 2. Art. No.: CD007176. DOI:10.1002/14651858.CD007176.