Some previous studies have suggested that antioxidant vitamins could delay the progression of atherosclerosis and thereby offer protection against cardiovascular disease. However no such benefit has been shown in large randomised trials.
Marc S Penn from the Cleveland Clinic Foundation, USA, and colleagues analysed seven randomised trials of treatment with vitamin E and eight trials of treatment with beta carotene (a source of vitamin A). All the trials included over 1000 participants, and follow-up ranged from one to twelve years.
Vitamin E was not beneficial in reducing death from cardiovascular causes, all-cause mortality, or in reducing the incidence of stroke compared with people given control treatment.
Beta carotene led to a small (0.4%) but statistically significant increase in all-cause mortality and a 0.3% increase in cardiovascular death.
Marc S Penn comments: "Given the results of this meta-analysis, the use of vitamin supplements containing beta carotene and vitamin A, beta carotene's biologically active metabolite, should be actively discouraged because this family of agents is associated with a small but significant excess of all-cause mortality and cardiovascular death. We recommend that clinical studies of beta carotene should be discontinued because of its risks. When used as secondary prevention, vitamin E did not reduce the risk of cardiovascular endpoints. Furthermore, given our results and the lack of mechanistic data supporting efficacy of vitamin E as a potent antioxidant in vivo, we do not support the continued use of vitamin E treatment and discourage the inclusion of vitamin E in future primary and secondary prevention trials in patients at high risk of coronary artery disease."
Contact: Alicia Sokol, Department of Public & Media Relations, Cleveland Clinic Foundation, W14, 9500 Euclid Avenue, Cleveland, OH 44195, USA,
T)216-445-9661,
F) 216-445-3040,
E) sokola@ccf.org
The Lancet