Warning on vitamin E cancer link
11 Oct 2011
Vitamin E can significantly increase the risk of men developing prostate cancer, a major study has shown.
The finding prompted a warning to men to be wary of vitamins and other health supplements.
Researchers made the discovery after attempting to confirm earlier reports that vitamin E and the mineral selenium could help prevent prostate cancer.
Instead they found that, in the case of vitamin E, the opposite was true.
Over several years of follow-up studies it became clear that vitamin E in moderate doses raised the risk of prostate cancer by more than would be expected by chance.
Compared with a “dummy” placebo, taking 400 international units (IU) of the vitamin a day increased the rate of prostate cancer detection by 17%.
The harmful effects appeared to continue long after men stopped taking the supplement, the study showed.
The findings were reported by US researchers led by Dr Eric Klein from the Cleveland Clinic in Chicago.
Writing in the Journal of the American Medical Association, they said: “Given that more than 50% of individuals 60 years or older are taking supplements containing vitamin E, and that 23% of them are taking at least 400 IU/d despite a recommended dietary allowance of only 22.4 IU for adult men, the implications of our observations are substantial.”
They added: “The lack of benefit from dietary supplementation with vitamin E or other agents with respect to preventing common health conditions and cancers or improving overall survival, and their potential harm, underscore the need for consumers to be sceptical of health claims of unregulated over-the-counter products in the absence of strong evidence of benefit demonstrated in clinical trials.”