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

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: supplementa tion (n 11) with 100 mg dl-alpha -tocopheryl acetate, 200 mg ascorbic acid, and 2 mg beta -carotene, and placebo (n 9). Before and after the 12 week s upplementation period, subjects cycled for 45 min at submaximal intensity ( 50 % maximal workload capacity). Antipyrine was used as marker for oxidativ e stress. Antipyrine reacts quickly with hydroxyl radicals to form para- an d ortho-hydroxyantipyrine. The latter metabolite is not formed in man throu gh the mono-oxygenase pathway of cytochrome P450. Daily supplementation sig nificantly increased plasma concentrations of alpha -tocopherol and beta -c arotene in the supplemented group (Delta 14.4 (se 3.2) and 0.4 (se 0.1) mu mol/l; P <0.001 and P <0.01). No significant differences, within and betwee n groups, were observed in the exercise-induced increase in the ratios para - and ortho-hydroxyantipyrine to antipyrine. In addition, supplementation d id not affect the exercise-induced increase in thiobarbituric acid reactive substances in plasma. In conclusion, in 60-year-old subjects antioxidant s upplementation had no effect on the exercise-induced increase in oxidative stress as measured by free radical products of antipyrine.