Muscle uptake of vitamin E and its association with muscle fiber type

The effect of 800 IU vitamin E (dl-α-tocopheryl acetate) supplementation for 30 days on α- and γ-tocopherol concentrations in gastrocnemius muscle and the relation between vitamin E concentrations and the distribution of Type I and II fibers was investigated in nine healthy adults (21 to 44 years). The plasma concentration of α-tocopherol increased by 300% (65.2 ± 7.7 versus 21.8 ± 2.3 μmol/L) and γ-tocopherol decreased by 74% (1.3 ± 0.1 vs. 3.2 ± 0.6 μmol/L) within 15 days of supplementation and was maintained at this plateau with continuous supplementation. Muscle biopsies taken before and after supplementation showed a significant 53% increase of α-tocopherol (37.3 ± 12.1 versus 37.6 ± 7.0 nmol/g) and a 37% decrease of γ-tocopherol (7.8 ± 1.1 versus 12.5 ± 1.1 nmol/g). There was a significant correlation between plasma and muscle concentrations of α- and γ-tocopherol (r = 0.71, P = 0.001 and r = 0.59, P = 0.009 respectively). Muscle α-tocopherol, but not γ-tocopherol, was inversely correlated with body mass index (r = -0.69, P = 0.008). The percentage of Type I fibers was inversely correlated with plasma concentrations of α-tocopherol (r = -0.69, P < 0.05), but this correlation with muscle concentrations of α-tocopherol was weak. It appears that individuals with a higher percentage of Type I fibers may utilize more α-tocopherol, perhaps to prevent oxidative damage from contractile activity.

Duke Scholars

Author William Joseph Evans Medicine, Geriatrics