Drugs Xagena
Previous research on animal and physiological models suggest that antioxidant supplements have beneficial effects that may prolong life. Some observational studies also suggest that antioxidant supplements may prolong life, whereas other observational studies demonstrate neutral or harmful effects. Randomised trials have largely been neutral.
A systematic review has included 67 randomised clinical trials. In total, 232,550 participants were randomised to antioxidant supplements ( Beta-carotene, Vitamin A, Vitamin C, Vitamin E, and Selenium ) versus placebo or no intervention.
Twenty-one trials included 164,439 healthy participants. Forty-six trials included 68111 participants with various diseases ( including gastrointestinal, cardiovascular, neurological, ocular, dermatological, rheumatoid, renal, endocrinological, or unspecified diseases ).
Overall, the antioxidant supplements did not seem to reduce mortality. A total of 17880 of 136,023 participants ( 13.1% ) randomised to antioxidant supplements and 10136 of 96527 participants ( 10.5% ) randomised to placebo or no intervention died.
In the analyses of the trials with low risk of bias, Beta-carotene, Vitamin A, and Vitamin E significantly increased mortality.
There were no significant differences between the effects of antioxidant supplements in healthy participants ( primary prevention trials ) or participants with various diseases ( secondary prevention trials ).
Randomised trials with adequate bias control found no significant effect of vitamin C.
In some of our analyses, Selenium seems to reduce mortality.
The current evidence does not support the use of antioxidant supplements in the general population or in patients with certain diseases.
The combined evidence suggests that additional research on antioxidant supplements is needed.
The evidence on vitamin C and selenium was not conclusive.
The present review does not assess antioxidant supplements for treatment of specific diseases ( tertiary prevention ), antioxidant supplements for patients with demonstrated specific needs of antioxidants, or the effects of antioxidants contained in fruits or vegetables.
Source: The Cochrane Database of Systematic Reviews, 2008
XagenaMedicine_2008
