Not so preventative: Antioxidant vitamins may still be good for you, but the evidence linking them to cancer protection is waning.
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SYDNEY: Vitamins C and E do not appear to reduce the risk of cancer, according to two large new studies refute earlier work suggesting that antioxidants have a protective effect.
"Neither vitamin E nor vitamin C supplementation reduced the risk of prostate or total cancer," says one of the reports, which are both to appear in January in the Journal of the American Medical Association (JAMA).
"These data provide no support for the use of these supplements in the prevention of cancer in middle-aged and older men," it says.
Disappointing news
The findings are disappointing news for many millions of people around the world who take vitamin supplements in the hope of warding off illness - and also for drug companies who make vast profits from selling them.
The research appears to debunk earlier observational studies that linked use of vitamins E and C with reduced risk of certain forms of cancers, including cancer of the prostate.
In the mid-1990s several trials seemed to suggest that antioxidants such as selenium, Vitamin E and beta carotene could significantly reduce the incidence of prostate cancer, commented Peter Gann a pathologist at the University of Illinois in Chicago, in an accompanying JAMA editorial.
"Now, 12 years later, comes the disappointing news that two major trials conceived during the wave of hope found that neither selenium nor vitamin E supplementation, alone or in combination, produced any reductions in prostate cancer or cancer of any type," said Gann who was not involved in the research.
SELECT study
Some 15,000 men aged 50 and older participated in the first study, led by J. Michael Gaziano of Harvard Medical School in Cambridge, Massachusetts. The trial included an eight-year follow-up period, but neither vitamin E or C appeared to appreciably reduce their cancer risk.
The second study, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) was led by Scott M. Lippman at the University of Texas M. D. Anderson Cancer Centre in Houston.
It found that vitamin E or selenium supplements, whether taken alone or in combination, appear not to reduce the risk of prostate cancer, which is the second leading cause of cancer death in the United States.
SELECT researchers studied the supplements' effects over seven years on some 35,533 men, aged 50 years or older.
"It may be time to give up the idea that the protective influence of diet on prostate cancer risk can be emulated by isolated dietary molecules given alone or in combination to middle-aged and older men," said Gann.
The authors of the research said that further "large-scale, randomised trials" must be conducted on the use of vitamin supplements and cancer.
Until that next generation of trials, "physicians should not recommend selenium or vitamin E or any other antioxidant supplements to their patients for preventing prostate cancer," said Gann.
With AFP.
