Supplements 'may damage health'

PEOPLE who buy antioxidant supplements such as grapeseed extract and effervescent vitamin C in the hope of avoiding a heart attack, cancer and other killer diseases may be wasting their money and even risking their health, according to experts.

In the 1990s, scientists began to suspect the main reason that eating lots of fruit and vegetables seemed to protect against such diseases was that they contain high levels of antioxidants such as flavonoids in red wine and beta carotene in carrots.

According to laboratory experiments, these were able to mop up free radicals, harmful by-products of breathing which have been linked to a number of life-threatening conditions.

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However, several experts, including pioneers of the early work on free radicals, now believe antioxidants behave in a radically different way in the body compared with the test tube, and many supplements on the market may do nothing at all, according to a report in New Scientist magazine.

There is even some tentative evidence that such supplements could be harmful to health.

Alan Crozier, professor of plant biochemistry and human nutrition at Glasgow University, said the situation was more complex than previously thought.

"If you are on an unhealthy diet, just taking vitamin A and C is not really going to do much good. I think people [who buy supplements] are wasting their money. They want something to spend their money on and it might make them live longer.

"In the vast majority of instances, there is no real evidence for which ones help and which ones don't. Nothing beats a healthy diet," he said. Professor Crozier added that antioxidants in high doses could be harmful.

"If you take lots of supplements, they act as pro-oxidants rather than antioxidants," he said.

Professor Barry Halliwell, of the National University of Singapore's biochemistry department, who pioneered research on free radicals and disease, said there had appeared to be a case for antioxidant supplements.

"Scientists assumed these antioxidants were protective and that taking them as supplements or in fortified foods should decrease oxidative damage and diminish disease," he said.

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Since then a number of trials failed to show any beneficial effects from taking supplements, suggesting that there is something else about fruit and vegetables that provides protection.

Prof Halliwell believes antioxidants in supplements might be digested too quickly, while in their natural state - in fibrous fruit and vegetables - they may stay in the digestive tract long enough to be beneficial. He advised people not to "start taking high-dose supplements or heavily [antioxidant] fortified foods, until we know more" and instead "stick to flavonoid-rich foods, red wine in moderation, tea, fruits and vegetables".

In the 1990s, scientists from the US National Cancer Institute began a six-year trial of beta carotene involving 18,000 people at high risk of getting lung cancer.

But four years later, they scrapped the study when figures showed those who were given the supplement had a 17 per cent higher death rate than those who were not.

Prof Halliwell added that healthy people also did not appear to benefit from taking regular doses of vitamin C.

"People are still trying to defend it, but you don't get an effect on free radical damage unless you start with people with a vitamin deficiency. I think it is a lost cause," he said.

No-one at Holland & Barrett, one of the biggest sellers of supplements on the high street, was available for comment.