Plasma antioxidant status and LDL oxidizability in healthy men after dietary supplementation with mixture of antioxidant nutrients

The oxidation of low-density lipoprotein (LDL) in the vascular wall has been postulated to play an important role in the development of atherosclerosis. Antioxidants can increase the resistance of LDL to oxidation and hence reduce its atherogenicity. The present study was undertaken to assess how a modest dietary supplementation with a mixture of antioxidant nutrients changes antioxidant status and LDL oxidizability in healthy volunteers. Forty-eight healthy men (mean age 45 years) participated in this placebo-controlled, randomised trial and were treated with placebo or mixture of antioxidants (100 mg vitamin E, 100 mg vitamin C, 6 mg beta-carotene and 50 mug of selenium per day) for 3 months. Plasma lipids, total antioxidant capacity, vitamin and malondialdehyde (MDA) levels and indices of LDL oxidizability (lag time and maximal rate of oxidation) were measured before and after supplementation. Plasma lipid, alpha-tocopherol and uric acid levels did not change significantly after supplementation, while ascorbic acid levels and total antioxidant capacity of plasma significantly increased. Beneficial effects of supplementation were observed with decreased plasma MDA levels and a prolonged lag time in LDL oxidation. In conclusion, a modest dietary supplementation with a mixture of antioxidant nutrients favourably affected plasma antioxidant status and MDA levels, and increased the resistance of LDL to oxidation in healthy volunteers.