In a systematic review and meta-analysis, the use of beta-carotene, vitamin A, and vitamin E, either alone or combined, was associated with an increased risk of all-cause mortality.
In a systematic review and meta-analysis published in the Journal of the American Medical Association (JAMA), the use of beta-carotene, vitamin A, and vitamin E, either alone or combined, was associated with an increased risk of all-cause mortality.
The authors stated that many people take antioxidant supplements in an effort to improve their health, but that there are no scientific data to determine the effects of the supplements.
This study involved 232,606 participants included in 68 randomized trials that compared various antioxidant supplements either alone or in combination (beta-carotene [n=25], vitamin A [n=16], vitamin C [n=34], vitamin E [n=55], and selenium [n=21]) with placebo or no therapy. Data were selected from a search of The Cochrane Library, MEDLINE, EMBASE, and the Science Citation Index Expanded. The primary objective of the analysis was to determine the effect of antioxidant supplements on all-cause mortality.
The authors stated that further research into the effects of antioxidant supplements is needed, especially to determine the effects of selenium and vitamin C.
SOURCE Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: Systematic review and meta-analysis. JAMA. 2007;297:842–857.