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There is little evidence that antioxidant supplements help prevent cancer. A review of research on selenium, beta carotene, and vitamins A, C and E found that apart from selenium there was no protection against gastrointestinal cancer. Selenium needs further study. The vitamin and mineral supplement industry is huge. As I've said before, we Australians have very expensive urine! Among the most popular supplements are antioxidants, invitingly marketed as mopping up all those nasty free radicals causing heart disease and cancer. There's no doubt that free radicals - damaging forms of oxygen - are linked to those diseases. What there is doubt about is whether swallowing antioxidant pills makes any difference. They don't for heart disease; the jury's still out on vitamin E and dementia; beta carotene probably increases the risk of lung cancer in smokers; and now there's been a review of the evidence on cancer of the gastrointestinal system - essentially from the throat to the anus including the pancreas and liver on the way. The news isn't good. In 14 trials involving about 170,000 men and women with an average age of 55, taking selenium, beta carotene, and vitamins A, C and E in combination or separately, the results showed that apart from selenium there was no protection against gastrointestinal cancer, and if anything the chances of dying may have been higher. The better quality the trial, the less likely it was to show an effect. Selenium was the exception but it needs more study to be sure.
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