Low‐fat milk protects against postprandial vascular endothelial dysfunction in adults with metabolic syndrome

Abstract

Vascular endothelial dysfunction (VED) is common in metabolic syndrome (MetS), likely due to greater oxidative stress. We hypothesized that low‐fat milk would protect against postprandial VED by limiting oxidative stress responses that decrease nitric oxide (NO) bioavailability. Adults with MetS (n = 19, 28±2 y) completed a randomized cross‐over study that examined the ingestion of low‐fat milk (475 mL) or an isocaloric volume of rice milk on brachial artery flow‐mediated dilation (FMD), plasma glucose, malondialdehyde (MDA), arginine (ARG), and asymmetric dimethylarginine (ADMA) during a 3 h postprandial period. Postprandial FMD was unaffected by low‐fat milk, but decreased at 30–60 min (P<0.01) following rice milk. Glucose and MDA increased to a greater extent (P<0.001) in the rice milk trial, and MDA AUC0–3 h was related (P<0.01) to glucose AUC0–3 h (r = 0.75), and inversely related to FMD AUC0–3 h (r = −0.59). Plasma ARG decreased in the rice milk trial and increased in the low‐fat milk trial whereas ADMA/ARG increased by only rice milk. ADMA/ARG AUC0–3 h was related (P<0.05) to MDA AUC0–3 h (r = 0.55), and inversely related to FMD AUC0–3 h (r = −0.52). These findings suggest that low‐fat milk is an effective dietary strategy to protect against postprandial VED in MetS individuals by preventing hyperglycemia‐mediated lipid peroxidation that decreases NO bioavailability. Supported by Dairy Research Initiative.