Dietary docosahexaenoic acid enhances ferric nitrilotriacetate-induced oxidative damage in mice but not when additional alpha-tocopherol is supplemented

Weaning mice were fed a diet supplemented with beef tallow (BT) or BT plus docosahexaenoic acid (DHA) containing 100 mg alpha-tocopherol/kg (alpha-Toc 100) or 500 mg alpha-tocopherol/kg (alpha-Toc500) for 4 wk to modify membra ne fatty acid unsaturation, and then were administered ferric nitrilotriace tate (Fe-NTA). The mortality caused by Fe-NTA was higher in the group fed t he DHA (alpha-Toc100) diet than in the BT diet groups but the DHA (alpha-To c500) diet suppressed this increase. Serum and kidney alpha-tocopherol cont ents were slightly influenced by the dietary fatty acids but not significan tly. These results indicate that the increased unsaturation of tissue lipid s enhances oxidative damage induced by Fe-NTA in mice fed DHA (alpha-Toc100 ) but not when additional alpha-tocopherol is supplemented. The apparent di screpancy between the observed enhancement by dietary DHA of oxidative dama ge and the beneficial effects of dietary DHA on the so-called free radical diseases is discussed in terms of strong bolus oxidative stress and moderat e chronic oxidative stress.