Մասնակից:Anahit.19/Ավազարկղ
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High doses of some antioxidants may have harmful long-term effects. The beta-Carotene and Retinol Efficacy Trial (CARET) study of lung cancer patients found that smokers given supplements containing beta-carotene and vitamin A had increased rates of lung cancer.[1] Subsequent studies confirmed these adverse effects.[2] These harmful effects may also be seen in non-smokers, as one meta-analysis including data from approximately 230,000 patients showed that β-carotene, vitamin A or vitamin E supplementation is associated with increased mortality, but saw no significant effect from vitamin C.[3] No health risk was seen when all the randomized controlled studies were examined together, but an increase in mortality was detected when only high-quality and low-bias risk trials were examined separately.[4] As the majority of these low-bias trials dealt with either elderly people, or people with disease, these results may not apply to the general population.[5] This meta-analysis was later repeated and extended by the same authors, confirming the previous results.[4] These two publications are consistent with some previous meta-analyses that also suggested that vitamin E supplementation increased mortality,[6] and that antioxidant supplements increased the risk of colon cancer.[7] Beta-carotene may also increase lung cancer.[7][8] Overall, the large number of clinical trials carried out on antioxidant supplements suggest that either these products have no effect on health, or that they cause a small increase in mortality in elderly or vulnerable populations.[9][10][3]