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.
The Melbourne Atherosclerosis Vitamin E Trial (MAVET): a study of high dose vitamin E in smokers.
Our aim was to evaluate whether vitamin E (500 IU) slowed the progression of carotid atherosclerosis in a population of chronic smokers over 4 years as measured by ultrasound determination of carotid intima-media thickness (IMT) and systemic arterial compliance (SAC).
                The Melbourne Atherosclerosis Vitamin E Trial (MAVET) was a randomized, double-blind, placebo-controlled trial in which 409 male and female smokers aged 55 years and over were randomized to receive 500 IU per day of natural vitamin E or placebo. The primary endpoint was progression of carotid atherosclerosis determined by intima-media thickness of the right common carotid artery. Secondary outcomes were change in systemic arterial compliance and low-density lipoprotein (LDL) oxidative susceptibility over time.
                The mean increase in intima-media thickness over time in the vitamin E group was 0.0041 mm/year faster than placebo (95% confidence interval -0.0021 to 0.0102 mm/year, P = 0.20). Similarly, a non-significant difference between vitamin E and placebo was found for rate of change in systemic arterial compliance (P = 0.11). Vitamin E supplementation did, however, significantly reduce LDL oxidative susceptibility (P < 0.001).
                Vitamin E supplementation is ineffective in reducing the progression of carotid atherosclerosis as measured by intima-media thickness in chronic smokers. This finding extends our knowledge of lack of effectiveness of vitamin E supplementation in populations with high oxidant stress.