Increased serum and low-density-lipoprotein antioxidant potential after antioxidant supplementation in endurance...

We studied the effect of antioxidant supplementation on acute exercise-induced lipid peroxidation and antioxidant potential measured in serum and low-density-lipoprotein (LDL) samples. Eight endurance athletes repeated a 31-km running exercise twice with an interval of 4 wk. During the 4 wk before the runs, the subjects took in a single-blind randomized order either a combination of antioxidant supplements (the antioxidant trial; 294 mg vitamin E, 1000 mg vitamin C, and 60 mg ubiquinone daily) or placebo (the placebo trial). Venous blood samples were taken before and immediately after the 31-km run in both trials. Antioxidant supplementation raised the LDL antioxidant potential (TRAP) (40% and 30%, P = 0.0031), serum TRAP (9% and 10%, P = 0.0037), and serum alpha-tocopherol concentration (by 59% and 66%, P = 0.0004) in both pre- and postexercise samples, respectively. The supplementation did not, however, affect the concentration of LDL diene conjugation (DC) or of serum DC. Physical exercise increased serum DC (by 18% and 10%, P = 0.0004) but not LDL-DC, and the quantity of the increment of serum DC was not affected by antioxidant intervention. The major cause for the increased LDL-TRAP and serum TRAP after antioxidant supplementation is apparently the elevation of the serum alpha-tocopherol concentration.