Pharmacologic 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 hyperinsulinemic glucose clamp before and after vitamin E supplementation (900 mg/d for 4 mo). In control subjects (placebo-treated vs vitamin E-supplemented subjects, respectively) vitamin E reduced the area under the curve for glucose (344 +/- 21 vs 287 +/- 13 mmol.L-1 x 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 x min-1; P < 0.05) and non-oxidative glucose metabolism (23.4 +/- 0.2 vs 30.8 +/- 0.3 mumol.kg lean body mass-1 x min-1; P < 0.05). In diabetics (placebo-treated vs vitamin E-supplemented subjects, respectively) vitamin E supplementation reduced glucose area under the curve (614 +/- 129 vs 544 +/- 98 mmol.L-1 x min-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 glucose disposal (19.0 +/- 0.7 vs 28.1 +/- 0.4 mumol.kg lean body mass-1 x min-1; P < 0.02), and nonoxidative glucose metabolism (8.5 +/- 0.3 vs 13.9 +/- 0.3 mumol.kg lean body mass-1 x min-1; P < 0.02). Therefore we conclude that administration of pharmacologic doses of vitamin E is a useful tool to reduce oxidative stress and improve insulin action.
Paolisso
G
G
Department of Geriatric Medicine and Metabolic Diseases, First Medical School, University of Naples, Italy.
D'Amore
A
A
Giugliano
D
D
Ceriello
A
A
Varricchio
M
M
D'Onofrio
F
F
D001774:Blood Chemical Analysis; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism; D004311:Double-Blind Method; D004357:Drug Synergism; D005260:Female; D005978:Glutathione / Q000031:analogs & derivatives / Q000097:blood; D019803:Glutathione Disulfide; D006801:Humans; D007328:Insulin / Q000378:metabolism / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D014810:Vitamin E / Q000008:administration & dosage / Q000378:metabolism / Q000627:therapeutic use*
D001786:Blood Glucose; D007328:Insulin; D014810:Vitamin E; D005978:Glutathione; D019803:Glutathione Disulfide