Effects of α-tocopherol and mixed tocopherol supplementation on markers of oxidative stress and inflammation in type 2 diabetes

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 53; no. 3; pp. 511 - 519
• Main Authors: WU, Jason H. Y, WARD, Natalie C, INDRAWAN, Adeline P, ALMEIDA, Coral-Ann, HODGSON, Jonathan M, PROUDFOOT, Julie M, PUDDEY, Ian B, CROFT, Kevin D
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for Clinical Chemistry 01.03.2007
• Subjects: alpha-Tocopherol - analysis; alpha-Tocopherol - therapeutic use; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Biomarkers - analysis; Diabetes Mellitus, Type 2 - diet therapy; Diabetes Mellitus, Type 2 - metabolism; Dietary Supplements; Double-Blind Method; Female; Fundamental and applied biological sciences. Psychology; Humans; Inflammation - diet therapy; Inflammation - metabolism; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Oxidative Stress; Tocopherols - analysis; Tocopherols - therapeutic use; Vitamins - analysis; Vitamins - therapeutic use; Endocrinopathy; Type 2 diabetes; Oxidative stress; Vitamin; Biological marker; Metabolic diseases; Biological indicator; α-Tocopherol; Biochemistry; Inflammation; Antioxidant; Mixed; Clinical biology; Supplementation; Molecular biology; Tocopherol
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/clinchem.2006.076992

Vitamin E isomers may protect against atherosclerosis. The aim of this study was to compare the effects of supplementation with either alpha-tocopherol (alphaT) or mixed tocopherols rich in gamma-tocopherol (gammaT) on markers of oxidative stress and inflammation in patients with type 2 diabetes. In a double-blind, placebo-controlled trial, 55 patients with type 2 diabetes were randomly assigned to receive (500 mg/day) (a) alphaT, (b) mixed tocopherols, or (c) placebo for 6 weeks. Cellular tocopherols, plasma and urine F(2)-isoprostanes, erythrocyte antioxidant enzyme activities, plasma inflammatory markers, and ex vivo assessment of eicosanoid synthesis were analyzed pre- and postsupplementation. Neutrophil alphaT and gammaT increased (both P <0.001) with mixed tocopherol supplementation, whereas alphaT (P <0.001) increased and gammaT decreased (P <0.005) after alphaT supplementation. Both alphaT and mixed tocopherol supplementation resulted in reduced plasma F(2)-isoprostanes (P <0.001 and P = 0.001, respectively) but did not affect 24-h urinary F(2)-isoprostanes or erythrocyte antioxidant enzyme activities. Neither alphaT nor mixed tocopherol supplementation affected plasma C-reactive protein, interleukin 6, tumor necrosis factor-alpha, or monocyte chemoattractant protein-1. Stimulated neutrophil leukotriene B(4) production decreased significantly in the mixed tocopherol group (P = 0.02) but not in the alphaT group (P = 0.15). 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 alphaT or mixed tocopherols rich in gammaT is unlikely to confer further benefits in reducing inflammation.