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Supplementation of a γ-tocopherol-rich mixture of tocopherols in healthy men protects against vascular endothelial dysfunction induced by postprandial hyperglycemia
- Source :
-
Journal of Nutritional Biochemistry . Jan2013, Vol. 24 Issue 1, p196-203. 8p. - Publication Year :
- 2013
-
Abstract
- Abstract: Postprandial hyperglycemia induces oxidative stress responses, impairs vascular endothelial function (VEF) and increases the risk of cardiovascular disease. We hypothesized that the antioxidant and anti-inflammatory activities of a γ-tocopherol-rich mixture of tocopherols (γ-TmT) would protect against vascular dysfunction that is otherwise caused by postprandial hyperglycemia by decreasing oxidative stress and proinflammatory responses, and improving nitric oxide (NO•) homeostasis. In a randomized, crossover study, healthy men (n=15; 21.8±0.8 years) completed a fasting oral glucose challenge (75 g) with or without prior supplementation of γ-TmT (5 days). Brachial artery flow-mediated dilation (FMD), plasma glucose, insulin, antioxidants, malondialdehyde (MDA), inflammatory proteins, arginine and asymmetric dimethylarginine (ADMA) were measured at regular intervals during a 3-h postprandial period. Supplementation of γ-TmT increased (P<.05) plasma γ-T by threefold and γ-carboxyethyl-hydroxychroman by more than ninefold without affecting α-T, glucose, arginine or ADMA. Baseline FMD, MDA, arginine and ADMA were unaffected by γ-TmT (P>.05). Postprandial FMD decreased 30%–44% (P<.05) following glucose ingestion, but was maintained with γ-TmT. Supplementation of γ-TmT also attenuated postprandial increases in MDA that occurred following glucose ingestion. Plasma arginine decreased (P<.05) in both trials to a similar extent regardless of γ-TmT supplementation. However, the ratio of ADMA/arginine increased time-dependently in both trials (P<.05), but to a lesser extent following γ-TmT supplementation (P<.05). Inflammatory proteins were unaffected by glucose ingestion or γ-TmT. Collectively, these findings support that short-term supplementation of γ-TmT maintains VEF during postprandial hyperglycemia possibly by attenuating lipid peroxidation and disruptions in NO• homeostasis, independent of inflammation. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 09552863
- Volume :
- 24
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Journal of Nutritional Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 83870053
- Full Text :
- https://doi.org/10.1016/j.jnutbio.2012.04.015