Effects of supplementation with a combination of antioxidant vitamins and trace elements, at nutritional doses, on biochemical indicators and markers of the antioxidant system in adult subjects

Objective: To test the impact of supplementation with nutritional doses of antioxidant nutrients on biochemical indicators of vitamin and trace element levels. Design: A randomized double-blind trial was performed comparing two groups receiving daily either a combination of vitamins (bera-carotene, 6 mg; vitamin C, 120 mg; and vitamin E, 30 mg) and trace elements (zinc, 20 mg; and selenium, 100 mu g); or a placebo. Subjects: 401 subjects (166 males aged 45 to 60 years and 235 females aged 35 to 60 years). Measure of outcome: Biological markers of vitamin and trace element status and free radical parameters were measured initially, 3 months, and 6 months after supplemention. Results: Mean serum concentrations of alpha-tocopherol, vitamin C, beta-carotene, zinc and selenium increased significantly after 3 months of supplementation in the group receiving multivitamins associated with minerals. At baseline, 18.2% of the men and 5.1% of the women had low concentrations of serum vitamin C (<20 mu mol/l); 2.4% of the men and 17% of the women presented low concentrations of serum retinol (<1.4 mu mol/l); 18.7% of men and 10% of women had serum beta-carotene <0.30 mu/mol/l. None of the study subjects had serum alpha-tocopherol concentrations below the limit cut-off point (<9.3 mu mol/l). Low serum zinc concentrations (<10.7 mu mol/l) were found in 15.1% of men and 23.8% of women. Low serum selenium concentrations (<0.75 mu mol/l) were found in 6% of men and 6.4% of women. A significant increase in plasma and red cell GPx activity was observed in groups receiving supplementation. No modifications were observed after 6 months of supplementation for malondyaldehyde. Conclusion: This study demonstrates the efficacy of an intake of antioxidant vitamins and trace elements, given at nutritional doses, on biochemical indicators of vitamin and trace elements status.