Effets biologiques des anti-oxydants : les données de l’étude SU.VI.MAX

The SU.VI.MAX study is a double blind, randomised, placebo-controlled trial testing, for 8 years, the effect of a combination of antioxidant vitamins and minerals, at doses considered to be nutritional (120 mg vitamin C, 30 mg vitamin E, 6mg beta-carotene, 100 lg selenium and 20 mg zinc) in reducing cancer and ischaemic vascular disease incidence in a general population (12,741 middleaged). After 7.5 years, low-dose antioxidant supplementation had no effect on vascular disease incidence. This dose lowered, however, total cancer incidence in men, but not in women. With regard to contradictory results of observational and interventional studies published for the last decades, we can consider that the effect of antioxidant on cancer may depend on the doses (nutritional versus pharmacological), baseline antioxidant status (different between gender and/or nutritional status) and health status of subjects (healthy versus cancer high-risk subjects). Antioxidant supplementation may have a beneficial effect on cancer incidence only in healthy subjects who are not exposed to cancer risk, and with a particularly low baseline status. Finally, antioxidants as well as free radicals appear to be ambiguous nutrients with a wide range of benefits and toxicity. High doses of antioxidant supplements may be deleterious in high-risk subjects without any clinical symptoms in whom the initial phase of cancer development has already started.