We found no evidence to support antioxidant supplements for primary or secondary prevention. Beta-carotene and vitamin E seem to increase mortality, and so may higher doses of vitamin A. Antioxidant supplements need to be considered as medicinal products and should undergo sufficient evaluation before marketing.
Incidence of cancers, ischemic cardiovascular diseases and mortality during 5-year follow-up after stopping antioxidant vitamins and minerals supplements: a postintervention follow-up in the SU.VI.MAX Study.
The Supplementation in Vitamins and Mineral Antioxidants Study was a double-blind, placebo-controlled, randomized trial, in which 12,741 French adults (7,713 women aged 35-60 years and 5,028 men aged 45-60 years) received a combination of ascorbic acid (120 mg), vitamin E (30 mg), beta-carotene (6 mg), selenium (100 microg) and zinc (20 mg), or placebo daily for a median follow-up time of 7.5 years [October 1994 to September 2002]. Antioxidant supplementation decreased total cancer incidence and total mortality in men. Postintervention follow-up assessment of total cancer incidence, ischemic cardiovascular disease incidence and total mortality was carried out for 5 years [September 1, 2002, to September 1, 2007]. No late effect of antioxidant supplementation was revealed 5 years after ending the intervention neither on ischemic cardiovascular disease incidence and mortality in both genders nor on cancer incidence in women. Regarding duration of intervention effects in men, the reduced risk of total cancer incidence and total mortality was no longer evident after the 5-year postintervention follow-up. During the postsupplementation period, the relative risk (RR) for total cancer incidence (n = 126) was 0.98 (95% confidence interval [CI], 0.75-1.27) among antioxidant recipients compared to nonrecipients. For total mortality (n = 90), the RR was 0.98 (95% CI, 0.75-1.26) for men receiving antioxidants compared to nonrecipients. In conclusion, beneficial effects of antioxidant supplementation in men disappeared during postintervention follow-up.