PROTECTIVE EFFECT OF VITAMIN-E ON EXERCISE-INDUCED OXIDATIVE DAMAGE IN YOUNG AND OLDER ADULTS

The protective effect of vitamin E supplementation on exercise-induced oxidative damage was tested in 21 male volunteers. Nine young (22-29 yr) and 12 older (55-74 yr) sedentary male subjects participated in a double-blind protocol and received either 800 IU dl-alpha-tocopherol o r a placebo daily. After 48 days, vitamin E supplementation significan tly increased alpha-tocopherol in plasma and skeletal muscle. Subjects then performed a bout of eccentric exercise at 75% of their maximum h eart rate by running down an inclined treadmill for 45 min. All vitami n E-supplemented subjects excreted less (P < 0.05) urinary thiobarbitu ric acid adducts after the exercise bout than placebo subjects at 12 d ays postexercise (35 and 18% above baseline in young and old supplemen ted groups, respectively, vs. 60 and 80% in young and old placebo grou ps, respectively). After exercise, the initial difference in alpha-toc opherol concentration of muscle between young placebo and vitamin E-su pplemented groups was diminished and muscle lipid conjugated dienes te nded to increase (P = 0.09) in placebo subjects. Placebo subjects had a significant decrease in major fatty acids of muscle biopsy taken imm ediately after exercise. When normalized for the hemoconcentration eff ects of exercise, the plasma concentration of vitamins E and C and uri c acid showed no significant change. The alterations in fatty acid com position, vitamin E, and lipid conjugated dienes in muscle and in urin ary lipid peroxides in controls after eccentric exercise are consisten t with the concept that vitamin E provides protection against exercise -induced oxidative injury.