Supplementary selenium influences the response to fatty acid-induced oxidative stress in humans

The mutual influences of wheat selenium (Se) andn-3 polyunsaturated fatty acids(n- 3 PUFA) on plasma Se and indicators of increased oxidative stress were investigated in a randomized, doubleblind study with 31 women (23.5 ±3.4 yr). Groups 1 and 2 ingested 5.4 g n-3 PUFA daily (as ethyl esters), whereas groups 3 and 4 received placebo capsules. Groups 2 and 3 received 3 slices of high Se bread daily, providing 115 Μg Se, in addition to the 77± 26 ug Se in the diet. Groups 1 and 4 received placebo slices. Blood samples were drawn at baseline and at 3 and 6 wk. Serum Se concentrations increased in both groups given Seenriched bread, but significantly less in subjects givenn-3 PUFA (group 2). There were no changes in the plasma ratio α-tocopherol:mg cholesterol or plasma ascorbic acid levels. In group1, plasmaconjugated dienes and thiobarbituric acid-reactive substances (TBARS) rose by 130% (p < 0.005) and 126% (p < 0.005), respectively. Two-way ANOVA showed significant interaction effects of Se andn-3 PUFA on changes in conjugated dienes (p = 0.03) and TBARS (p = 0.015), Se treatment apparently modifying the peroxidative effects ofn-3 PUFA. In subjects receivingn-3 PUFA, changes in conjugated dienes and TBARS were negatively correlated with changes in serum Se. In summary,n-3 PUFA modified the effect of Se supplementation, whereas Se seemed to modify the peroxidative effects ofn-3 PUFA.