Moderate doses of dietary nitrate elicit greater effects on blood pressure and endothelial function than a high dose:...

Few 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.

Sixty-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.

This 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.

These 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.