Premium
γ‐tocopherol supplementation improves postprandial vascular endothelial function in lean and obese men
Author(s) -
Mah Eunice,
Diaz Manuel Matos,
Kawiecki Diana,
Volek Jeff S,
Bruno Richard
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.729.10
Subject(s) - postprandial , oxygen radical absorbance capacity , medicine , endocrinology , ferric reducing ability of plasma , crossover study , endothelial dysfunction , antioxidant , insulin , antioxidant capacity , oxidative stress , chemistry , biochemistry , placebo , alternative medicine , pathology
Acute hyperglycemia is associated with oxidative stress and impaired vascular endothelial function (VEF). Thus, we hypothesized that postprandial hyperglycemia would impair VEF by affecting plasma antioxidants. In a randomized, crossover study, lean and obese men (n=8/group) followed their usual diet or were provided γ‐tocopherol (γ‐T)‐rich capsules (500 mg/d, 5 d) prior to a fasting 75 g oral glucose challenge. Flow‐mediated dilation (FMD), plasma glucose, insulin, and antioxidant capacity were measured before and during the 3 h postprandial period. Insulin resistance (HOMA) was greater in obese (6.7±3.5) than lean men (3.9±2.0, p<0.05) and unaffected during the study. Postprandial FMD area under the curve (AUC) of obese men was 32% lower (p=0.02) than lean men. FMD AUC was 31% (p=0.006) higher in all men post‐γ ‐T supplementation relative to the control trial. Baseline oxygen radical absorbance capacity (ORAC), but not ferric reducing ability of plasma (FRAP), was lower (p=0.039) in obese compared to lean men. Postprandial FRAP, but not ORAC, was higher (p=0.027) with γ‐T supplementation regardless of group. These data suggest that obesity impaired VEF and that γ‐T‐rich vitamin E supplements improve VEF possibly by enhancing antioxidant capacity. Additional study is underway to define the protective effects of γ‐T on VEF. Support provided by a grant from International Life Sciences Institute to RSB. Grant Funding Source International Life Sciences Institute