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

BACKGROUND & AIMS: 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 (NO), provided as beetroot juice (BJ), on blood pressure (BP) and endothelial function in overweight and obese older participants.

METHODS AND RESULTS

Sixty-two overweight or obese older participants (60-75 years) were randomized to the following interventions: (1) high NO (2) medium NO, (3) low NO, 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.

RESULTS

This pilot study showed that medium and low doses of NO were more effective in lowering resting-clinic SBP (P = 0.04 and, P = 0.03, respectively) than was PL. The lower doses of NO also resulted in significant increases in microvascular perfusion (medium, P = 0.02; low, P = 0.002) relative to baseline values.

CONCLUSION

These findings indicate that supplementation with medium and low, but not high, doses of NO for 13 weeks had positive effects on BP and endothelial function in older overweight and obese adults. These findings require confirmation in larger studies.