Background: Abnormalities during the postprandial state contribute to the development of atherosclerosis. Reportedly, postprandial hyperglycemia, hypertriglyceridemia, and hyperlipacidemia independently cause postprandial cytokine activation. However, it is not clear which dietary composition preferentially affects postprandial endothelial function in healthy subjects.

Objective: We aimed to examine the associations of dietary composition and postprandial endothelial function in healthy subjects.

Design: The effects of a single ingestion of a high-carbohydrate meal (300 kcal, 100% carbohydrate), a high-fat meal (30 g fat/m2, 35% fat), or a standard test meal (478 kcal; 16.4% protein, 32.7% fat, 50.4% carbohydrate) on postprandial plasma concentrations of adiponectin and forearm blood flow (FBF) during reactive hyperemia were studied in healthy subjects.

Results: The peak FBF response and the total reactive hyperemic flow (flow debt repayment; FDR), indexes of resistance artery endothelial function, were unchanged after ingestion of a high-carbohydrate and standard test meal but decreased 120 and 240 min after a high-fat meal. After a high-fat meal, decreases in peak FBF and FDR were well correlated with an increase in plasma free fatty acid (FFA) concentrations but not with the other biochemical variables, including triacylglycerol, insulin, glucose, total cholesterol, HDL cholesterol, and adiponectin.

Conclusions: Postprandial endothelial function was impaired only after the high-fat diet and not after the high-carbohydrate or standard test meal in healthy subjects. Because such endothelial dysfunction after a high-fat meal was closely correlated with FFA concentrations, postprandial state could be hazardous, mostly through acute hyperlipacidemia in healthy subjects.