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

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.