| Endothelial dysfunction has been linked to the pathogenesis of atherosclerotic vascular disease and predicts future cardiovascular events in patients with or without cardiovascular disease. We evaluated the impact of two distinctly different meal challenges and diets on brachial artery reactivity in subjects with elevated risk for cardiovascular disease and type 2 diabetes. Ten subjects (7 females, 3 males, age 44.7 +/- 7.8 years, BMI 34.4 +/- 5.4 kg/m 2, mean +/- SD) who have the metabolic syndrome participated. In a single-blinded, crossover design, each participant underwent two single-meal challenges and two 28-day dietary phases.;The low-carbohydrate (LC) meal was comprised of 12-16% carbohydrate (0.5 g fiber), 58-61% fat [16.5-25.2 g of saturated fatty acids (SFA), 14.5-20.3 g of monounsaturated fatty acids (MUFA), 5.4-7.1 g of polyunsaturated fatty acids (PUFA), and < 1 g of trans fatty acids (TFA)], and 26-28% protein, and the high-carbohydrate, high-fiber meal was comprised of 69-76% carbohydrate (19 g fiber from whole grains), 12-18% fat (1.9-6.4 g of SFA, 3.6-4.0 g of MUFA, 1.9-2.5 g of PUFA, and 1.9 g of TFA), and 13-15% protein.;The low-carbohydrate diet contained 15-20% carbohydrate (8.6-10.85 g/day of fiber), 55-60% fat [38-67 g of saturated fatty acids (SFA), 33-57 g of monounsaturated fatty acids (MUFA), 15.5-37 g of polyunsaturated fatty acids (PUFA), and 3-4.4 g of trans fatty acids (TFA)], and 25-30% protein, and the high-carbohydrate diet contained 55-60% carbohydrate (38-48 g/day of fiber), 20-25% fat (13-21 g of SFA, 21-30 g of MUFA, 13.4-18.7 g of PUFA, and < 2 g of TFA), and 15-20% protein.;Meal and diet order was randomized, followed by a 4-week washout period. Brachial artery flow-mediated dilation (FMD) and response to sublingual glyceryltrinitrate (GTN) were assessed using high-resolution ultrasound and edge detection software to examine endothelial function. A 2 x 2 ANOVA with repeated measures revealed significant changes in the vascular response of the brachial artery to the two acute-meal challenges and to the high-carbohydrate, high-fiber diet. A single high-carbohydrate, high-fiber meal significantly improved flow-mediated dilation (pre 8.90 +/- 4.56%, post 11.59 +/- 4.73%, p = 0.0013); whereas, a low-carbohydrate meal significantly decreased flow-mediated dilation (pre 8.57 +/- 2.74%, post 6.26 +/- 3.43%; p = 0.006). There was a significant increase in flow-mediated dilation observed following the high-carbohydrate, high-fiber diet (pre 8.89 +/- 4.56%, post 11.70 +/- 5.83%, p = 0.02) and a non significant decrease was observed following the low-carbohydrate diet (pre 8.57 +/- 2.74%, post 6.57 +/- 4.92%, p = 0.15). (Abstract shortened by UMI.)... |
