Moderate doses of dietary nitrate elicit greater effects on blood pressure and endothelial function than a high dose: A 13-week pilot study

Abstract

Background & aimsFew studies have explored the prolonged effects of dietary nitrate on vascular health. This pilot study tested the effects of prolonged consumption (13 weeks) of a range of doses of dietary nitrate (NO3−), provided as beetroot juice (BJ), on blood pressure (BP) and endothelial function in overweight and obese older participants. Methods and resultsSixty-two overweight or obese older participants (60–75 years) were randomized to the following interventions: (1) high NO3− (2) medium NO3−, (3) low NO3−, or (4) placebo. Resting clinic and home BP were measured pre- and post-intervention. Laser Doppler iontophoresis was used to quantify changes in endothelial-dependent and independent microvascular blood flow. ResultsThis pilot study showed that medium and low doses of NO3− were more effective in lowering resting-clinic SBP (P = 0.04 and, P = 0.03, respectively) than was PL. The lower doses of NO3− also resulted in significant increases in microvascular perfusion (medium, P = 0.02; low, P = 0.002) relative to baseline values. ConclusionThese findings indicate that supplementation with medium and low, but not high, doses of NO3− for 13 weeks had positive effects on BP and endothelial function in older overweight and obese adults. These findings require confirmation in larger studies.