The importance of dietary antioxidants on plasma antioxidant capacity and lipid peroxidation in vivo in middle-aged men

Abstract

Background: High intake of foods rich in antioxidants is associated with a reduced risk of several diseases, including coronary heart disease and some cancers. Objective: To study associations between dietary antioxidants and antioxidant-rich food items and antioxidant capacity (AOC), as well as lipid peroxidation in vivo. Design: A total of 86 men, with a mean age of 60 years, who were part of a larger population-based study in Sweden, participated. Fourteen 24 h recalls were collected by telephone, evenly distributed during 1 year. AOC was measured in plasma using an enhanced chemiluminescence assay and biomarkers of non-enzymic in vivo lipid peroxidation were determined by measuring F2-isoprostanes (8-iso-prostaglandin F2a) in plasma. Results: Higher intakes of ascorbic acid, tocopherols and b-carotene, and of the combined intake of different antioxidant-rich foods, were related to a higher plasma AOC. The levels of F2-isoprostanes were related neither to dieta ry intake of antioxidants nor to antioxidant-rich foods. Conclusions: Individuals with a higher intake of several different antioxidant-rich foods and of dietary antioxidants had a higher plasma AOC than those with the lowest intake, supporting the importance of a balanced diet rich in various antioxidants. Moreover, the results indicate that non-enzymic lipid peroxidation in vivo, measured as F2-isoprostanes in plasma, is not easily affected by the diet. Keywords: antioxidant status; diet; food habits; isoprostanes; oxidative stress