Antioxidant supplementation and exercise-induced oxidative stress in the 60-year-old as measured by antipyrine hydroxylates

Abstract

The effects of 12 weeks of antioxidant supplementation on exercise-induced oxidative stress were investigated in older adults (60 (SE 1) YEARS; BMI 26 (se 1) kg/m 2 ). Subjects were randomly divided in two groups: supplementation ( n 11) with 100 mg dl-α-tocopheryl acetate, 200 mg ascorbic acid, and 2 mg β-carotene, and placebo ( n 9). Before and after the 12 week supplementation period, subjects cycled for 45 min at submaximal intensity (50 % maximal workload capacity). Antipyrine was used as marker for oxidative stress. Antipyrine reacts quickly with hydroxyl radicals to form para - and ortho -hydroxyantipyrine. The latter metabolite is not formed in man through the mono-oxygenase pathway of cytochrome P450. Daily supplementation significantly increased plasma concentrations of α-tocopherol and β-carotene in the supplemented group (Δ 14·4 (se 3·2) and 0·4 (se 0·1) μmol/l; P <0·001 and P <0·01). No significant differences, within and between groups, were observed in the exercise-induced increase in the ratios para - and ortho -hydroxyantipyrine to antipyrine. In addition, supplementation did not affect the exercise-induced increase in thiobarbituric acid reactive substances in plasma. In conclusion, in 60-year-old subjects antioxidant supplementation had no effect on the exercise-induced increase in oxidative stress as measured by free radical products of antipyrine.