Beetroot juice improves in overweight and slightly obese men postprandial endothelial function after consumption of a mixed meal

Abstract

Background: Through effects on nitric oxide (NO) bioavailability, endothelial function is improved after the intake of beetroot juice-which is rich in inorganic nitrate-, but decreased after the intake of a meal.

Objective: The objective of this study was to examine if beetroot juice could counteract the impairment of endothelial function associated with the ingestion of a mixed meal.

Methods: Twenty healthy overweight and slightly obese men with a BMI between 28 and 35 kg/m(2) received in random order a mixed meal providing 56.6 g of fat with beetroot juice or a control drink. The beetroot juice (140 mL) provided approximately 500 mg dietary nitrate. Flow-mediated dilation (FMD) of the brachial artery was measured before and 2 h after meal consumption. Blood was sampled at regular intervals.

Results: Postprandial changes in serum triacylglycerol (TAG) (P = 0.69), plasma glucose (P = 0.84) and insulin (P = 0.67) concentrations were comparable between the meals. After consumption of beetroot juice, the postprandial impairment in FMD following a standardized mixed meal was improved (P = 0.030) compared with the control drink (-0.37 ± 2.92% versus -1.56 ± 2.90%). Following beetroot juice consumption, plasma concentrations of the circulating NO pool were higher at T60, T120, and T240 (P < 0.001 at all time points).

Conclusion: In healthy overweight and slightly obese men a single dose of beetroot juice attenuates the postprandial impairment of FMD following a mixed meal, possibly through increases in plasma NO concentrations.

Keywords: Beetroot juice; Endothelial dysfunction; Flow-mediated dilation; Inorganic nitrate; Postprandial lipemia.