Lipid peroxidation and antioxidant supplementation in old age

An age-related rise in blood lipid peroxides measured by the thiobarbituric acid (TBA) method has been reported in several studies. Our study was designed to investigate whether this could be attributed to antioxidant deficiencies in aged individuals. We therefore measured the TBA-value of young and old women and related this to vitamin E and selenium status and the fatty acid composition, triglyceride and cholesterol content of platelet-poor plasma. A significant difference (p less than 0.001) between young and old women in the plasma TBA-value and the plasma lipid parameters was found. Old women had a lower selenium status than the young women (p less than 0.01), but their vitamin E status was fully adequate. Only the lipid parameters correlated significantly (p less than 0.001) with the TBA-value. In a 3-month placebo-controlled supplementation trial with vitamin E and selenium, the plasma TBA-value of the old women did not change. This study shows that the TBA-value of plasma is primarily determined by the fatty acid content and is not influenced by antioxidant supplementation in healthy individuals. The question of the sensitivity of the TBA-test is discussed.