Yesterday, I wrote about research that debunked the notion that garlic supplements could lower LDL cholesterol. Today it's more bad news for the supplement industry with a report of a meta-analysis study that examines the effects of antioxidants on mortality.

A range of different vitamins and minerals have been identified as having antioxidant properties, including vitamins A and C, beta carotene and selenium. Although a well-balanced diet with plenty of fresh fruit and vegetables contains ample amounts of these antioxidants, an army of talking heads and 'experts' make their living by promoting the use of supplementary antioxidants at ever-increasing doses as cure-alls against cancer, aging, and any number of other ailments. Even Linus Pauling, noted Nobel Laureate, spent the latter years of his career claiming that vitamin C was a panacea for just about every complaint he could think of.

However, a new meta-analysis of existing studies published in JAMA regarding the use of antioxidant supplements shows that far from prolonging longevity, beta carotene, vitamin A, and vitamin E usage were associated with increased mortality. Dr Bjelakovic and his team at Copenhagen University Hospital identified 68 different trials, encompassing 232,606 patients in total. These were sorted into high-bias risk and low-bias risk, based on the quality of the methods employed.

When all of these trials were pooled there was no significant finding, but when the 47 low-bias trials were examined, there was a five percent increased risk of mortality. Individually, beta carotene increased risk of mortality by seven percent, vitamin A increased risk of mortality by 16 percent, and vitamin E increased risk of mortality by four percent.

Although this is contrary to common sense, the authors suggest a reason for this finding. Although antioxidant production is associated with a number of diseases, many physiologic processes also involve free radical generation. They propose that "eliminating free radicals from our organism, we interfere with some essential defensive mechanisms like apoptosis, phagocytosis, and detoxification." As ever, the best advice would seem to be to make sure you get those five portions of fresh fruit and vegetables a day, and lay off the pills.