Increase in oxidation resistance of atherogenic serum lipoproteins following antioxidant supplementation: a randomized double-blind placebo-controlled clinical trial

Abstract

Objective: To test the effect of supplementation of diet with ascorbic acid, selenium, alpha-tocopherol and beta-carotene on the oxidation resistance of very low (VLDL) + low density lipoprotein (LDL).

Design: A randomized placebo-controlled double-masked clinical trial.

Setting: In healthy men aged 30-58 years smoking regularly 15-40 cigarettes/day.

Subjects: Forty subjects recruited from the general population, who all completed the study.

Intervention: 400 mg of slow release ascorbic acid, 100 micrograms of organic selenium, 200 mg of D-alpha-tocopheryl acetate and 30 mg of beta-carotene daily or placebo, 20 men in each group for 3 months.

Main outcome measures: The oxidation resistance of VLDL + LDL measured by inducing oxidation with copper chloride and, separately, with a combination of haemin and H2O2.

Results: In plasma, alpha-tocopherol increased by 72%, beta-carotene by 209%, ascorbate by 45% and selenium by 20% in the supplemented men. The lag time to oxidation increased by 27% [95% confidence interval (CI) 18-35%, P < 0.001] after copper and by 29% (95% CI 12-46%, P = 0.002) after haemin plus H2O2 in the supplemented group as compared to the placebo group by t-tests. The respective net changes in the maximal oxidation velocity were a reduction of 10% (95% CI 1-21%, P = 0.037) after copper and a reduction of 15% (95% CI-1 to 30%, P = 0.070) after haemin and H2O2.

Conclusions: These findings provide further confirmation for the notion that the supplementation of diet with antioxidative vitamins and selenium increases the oxidation resistance of atherogenic lipoproteins in human plasma.