Contraction-induced muscle damage is unaffected by vitamin E supplementation

BEATON, L. L, D. A. ALLAN, M. A. TARNOPOLSKY, P. M. TIIDUS. and S. M. PHILLIPS. Contraction-induced muscle damage is unaffected by vitamin E supplementation. Med. Sci. Sports Exerc., Vol. 34. No. 5, pp. 798-805, 2002. Purpose: Vitamin E supplementation may confer a protective effect against eccentrically biased exercise-induced muscle damage through stabilization of the cell membrane and possibly via inhibition of free radical formation. Evidence supporting a protective role of vitamin E after contraction-induced muscle injury in humans is, however, inconsistent. The present study sought to determine the effect of vitamin E supplementation on indices of exercise-induced muscle damage and the postexercise inflammatory response after performance of repeated eccentric muscle contractions. Methods: Young healthy men performed a bout of 240 maximal isokinetic eccentric muscle contractions (0.52 rad.s(-1)) after being supplemented for 30 d with either vitamin E (N = 9: 1200 IU.d(-1)) or placebo (N = 7: safflower oil). Results: Measurements of torque (isometric and concentric) decreased (P < 0.05) below preexercise values immediately post- and at 48 h post-exercise. Biopsies taken 24 It postexercise showed a significant increase in the amount of extensive Z-band disruption (P < 0.01); however. neither the torque deficit nor the extent of Z-band disruption were affected by vitamin E. Exercise resulted in increased macrophage cell infiltration (P = 0.05) into muscle, which was also unaffected by vitamin E. Serum CK also increased as a result of the exercise (P < 0.05) with no effect of vitamin E. Conclusion: We conclude that vitamin E supplementation (30 d at 1200 IU.d(-1)), which resulted in a 2.8-fold higher serum vitamin E concentration (P < 0.01), had no affect on indices of contraction-induced Muscle damage nor inflammation (macrophage infiltration) as a result of eccentrically biased muscle contractions.