Vitamin E supplementation restores glutathione and malondialdehyde to normal concentrations in erythrocytes of type 1 diabetic children

OBJECTIVE - This study examined the relationship between cellular glutathio ne and vitamin E concentrations and the effect of vitamin E (alpha-tocopher ol) supplementation on glutathione and lipid peroxidation product concentra tions in the erythrocytes of type 1 diabetic patients. RESEARCH DESIGN AND METHODS - We obtained written informed consent to parti cipate in this study from diabetic patients (n = 29) and their age-matched nondiabetic siblings (n = 21) according to the guidelines of the Institutio nal Review Board on Human Experimentation Diabetic patients were supplement ed with a DL-alpha-tocopherol (vitamin E) capsule (100 IU/ orally) or place bo for 3 months in a double-blind clinical trial. Fasting blood samples wer e collected from each diabetic patient before the start of and after the 3 months of vitamin E or placebo supplementation. Glutathione, malondialdehyd e (which is a product of lipid per oxidation), and alpha-tocopherol were de termined using high-performance liquid chromatography. A total of 5 diabeti c patients were excluded after randomization from the data analyses. Data w ere analyzed statistically using a paired Student's 1 test to compare 12 di abetic patients taking vitamin E with 12 diabetic patients receiving placeb o supplementation and to compare diabetic patients with healthy nondiabetic subjects. RESULTS - Erythrocytes of diabetic patients had 21% higher (P < 0.001) malo ndialdehyde and 15% lower (P < 0.05) glutathione concentrations than health y subjects. Vitamin E in ery- throcytes had a significant correlation with the glutathione concentrations in the erythrocytes (r = 0.46, P < 0.02). Vi tamin E supplementation increased glutathione concentrations by 9% (P < 0.0 1) and lowered concentrations of malondialdehyde by 23% (P < 0.001) and of HbA(1c) by 16% (P < 0.02) in erythrocytes of diabetic patients. No differen ces were evident in these parameters before versus after placebo supplement ation. CONCLUSIONS - Glutathione level is significantly related to vitamin E level , and supplementation with vitamin E (100 IU/day) significantly increases g lutathione and lowers lipid peroxidation and HbA(1c) concentrations in the erythrocytes of type 1 diabetic patients.