Abstract
Background: Vitamin E isomers may protect against atherosclerosis. The aim of this study was to compare the effects of supplementation with either α-tocopherol (αT) or mixed tocopherols rich in γ-tocopherol (γT) 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) αT, (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 pre- and postsupplementation.
Results: Neutrophil αT and γT increased (both P <0.001) with mixed tocopherol supplementation, whereas αT (P <0.001) increased and γT decreased (P <0.005) after αT supplementation. Both αT 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 αT nor mixed tocopherol supplementation affected plasma C-reactive protein, interleukin 6, tumor necrosis factor-α, or monocyte chemoattractant protein-1. Stimulated neutrophil leukotriene B4 production decreased significantly in the mixed tocopherol group (P = 0.02) but not in the αT 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 αT or mixed tocopherols rich in γT is unlikely to confer further benefits in reducing inflammation.
Effect of Dietary Vitamin E, Selenium and Their Combination on Concentration of Selenium, MDA, and Antioxidant Enzyme Activities in Some Tissues of Laying Hens
