The effects of lipoic acid and α-tocopherol supplementation on the lipid profile and insulin sensitivity of patients with type 2 diabetes mellitus: a randomized, double-blind, placebo-controlled trial.

Antioxidants probably play an important role in the etiology of type 2 diabetes (DM2). This study evaluated the effects of supplementation with lipoic acid (LA) and α-tocopherol on the lipid profile and insulin sensitivity of DM2 patients. A randomized, double-blind, placebo-controlled trial involving 102 DM2 patients divided into four groups to receive daily supplementation for 4 months with: 600 mg LA (n = 26); 800 mg α-tocopherol (n = 25); 800 mg α-tocopherol + 600 mg LA (n = 25); placebo (n = 26). Plasma α-tocopherol, lipid profile, glucose, insulin, and the HOMA index were determined before and after supplementation. Differences within and between groups were compared by ANOVA using Bonferroni correction. Student's t-test was used to compare means of two independent variables. The vitamin E/total cholesterol ratio improved significantly in patients supplemented with vitamin E+LA and vitamin E alone (p ≤ 0.001). There were improvements of the lipid fractions in the groups receiving LA and vitamin E alone or in combination, and on the HOMA index in the LA group, but not significant. The results suggest that LA and vitamin E supplementation alone or in combination did not affect the lipid profile or insulin sensitivity of DM2 patients.