PHARMACOLOGICAL DOSES OF VITAMIN-E IMPROVE INSULIN ACTION IN HEALTHY-SUBJECTS AND NON-INSULIN-DEPENDENT DIABETIC-PATIENTS

Ten control (healthy) subjects and 15 non-insulin-dependent diabetics underwent an oral glucose-tolerance test and a euglycemic hyperinsulin emic glucose clamp before and after vitamin E supplementation (900 mg/ d for 4 mo). In control subjects (placebo-treated vs vitamin E-supplem ented subjects, respectively) vitamin E reduced the area under the cur ve for glucose (344 +/- 21 vs 287 +/- 13 mmol . L-1 . min-1; P < 0.05) and increased total body glucose disposal (39.0 +/- 0.3 vs 47.6 +/- 0 .4 mumol . kg lean body mass-1 . min-1; P < 0.05) and non-oxidative gl ucose metabolism (23.4 +/- 0.2 vs 30.8 +/- 0.3 mumol . kg lean body ma ss-1 . min-1; P < 0.05). In diabetics (placebo-treated vs vitamin E-su pplemented subjects, respectively) vitamin E supplementation reduced g lucose area under the curve (614 +/- 129 vs 544 +/- 98 mmol . L-1 . mi n-1; P < 0.03) and increased glucose disappearance (19.4 +/- 0.4 vs 26 .4 +/- 0.7 mumol . kg lean body mass-1 . min-1; P < 0.03), total gluco se disposal (19.0 +/- 0.7 vs 28.1 +/- 0.4 mumol . kg lean body mass-1 . min-1; P < 0.02), and nonoxidative glucose metabolism (8.5 +/- 0.3 v s 13.9 +/- 0.3 mumol . kg lean body mass-1 . min-1; P < 0.02). Therefo re we conclude that administration of pharmacologic doses of vitamin E is a useful tool to reduce oxidative stress and improve insulin actio n.