Effects of -Tocopherol and Mixed Tocopherol Supplementation on Markers of Oxidative Stress and Inflammation in Type 2 Diabetes

Background: Vitamin E isomers may protect against atherosclerosis. The aim of this study was to compare the effects of supplementation with either -tocopherol ( T) or mixed tocopherols rich in -tocopherol ( T) on markers of oxidative stress and inflammation in patients with type 2 diabetes. Methods: In a double-blind, placebo-controlled trial, 55 patients with type 2 diabetes were randomly assigned to receive (500 mg/day) (a) T, (b) mixed tocopherols, or (c) placebo for 6 weeks. Cellular tocopherols, plasma and urine F2-isoprostanes, erythrocyte antioxidant enzyme activities, plasma inflammatory markers, and ex vivo assessment of eicosanoid synthesis were analyzed preand postsupplementation. Results: Neutrophil T and T increased (both P <0.001) with mixed tocopherol supplementation, whereas T (P <0.001) increased and T decreased (P <0.005) after T supplementation. Both T and mixed tocopherol supplementation resulted in reduced plasma F2-isoprostanes (P <0.001 and P 0.001, respectively) but did not affect 24-h urinary F2-isoprostanes or erythrocyte antioxidant enzyme activities. Neither T nor mixed tocopherol supplementation affected plasma C-reactive protein, interleukin 6, tumor necrosis factor, or monocyte chemoattractant protein-1. Stimulated neutrophil leukotriene B4 production decreased significantly in the mixed tocopherol group (P 0.02) but not in the T group (P 0.15). Conclusions: The ability of tocopherols to reduce systemic oxidative stress suggests potential benefits of vitamin E supplementation in patients with type 2 diabetes. In populations with well-controlled type 2 diabetes, supplementation with either T or mixed tocopherols rich in T is unlikely to confer further benefits in reducing inflammation. © 2007 American Association for Clinical Chemistry