Changes in meal composition and duration affect postprandial endothelial function in healthy humans

Abstract

Background: Endothelial function, measured by flow-mediated dilatation (FMD), predicts cardiovascular events, and is impaired postprandially. Objective: To evaluate the effects of changes in composition or duration of ingestion of a meal, which slows gastric emptying and/or small intestinal nutrient exposure, on postprandial endothelial function. Design: 12 healthy subjects (6 male, 6 female; 33 ± 6 years) were each studied on 3 occasions, in a randomised, crossover design. After an overnight fast, subjects consumed a (13)C-octanoic acid labeled mashed potato meal ('meal 1'), or 'meal 1' mixed with 9 g guar ('meal 2') within 10 min, or 'meal 1' divided into 12 equal portions over 60 min ('meal 3'). Brachial artery FMD was measured every 30 min for 120 min. Blood glucose, serum insulin, and gastric emptying (breath test), were evaluated for 240 min. Data are means ± SEM. Results: Compared to 'meal 1', 'meal 2' was associated with slower gastric emptying (half-emptying time 285 ± 27 vs. 208 ± 15 min, P < 0.05), lower postprandial blood glucose and insulin (P < 0.001 for both), and a delayed, but more sustained, suppression of FMD (P < 0.001). After 'meal 3', both glycemic increment and reduction in FMD were less than after 'meal 2' (P < 0.05 for both). The decrement in FMD was directly related to the increment in blood glucose (r = 0.46, P = 0.02). Conclusions: In health, postprandial FMD is influenced by perturbation of gastric emptying and the duration of meal consumption, which also impact on glycemia.