Could daily beetroot juice lower blood pressure in people with hypertension?

Details

A single dose of dietary inorganic nitrate is known to acutely lower blood pressure in healthy volunteers with normal blood pressure through conversion to nitric oxide, a blood-vessel dilator. The researchers assessed whether dietary nitrate could provide sustained blood pressure lowering in patients with hypertension.

In a randomized, double-blind, placebo-controlled clinical trial, 68 patients received either 250 mL of nitrate-containing beetroot juice or 250 mL of nitrate-free beetroot juice daily for four weeks, after a two-week run-in and before a two-week washout. Participants were aged 18–85 years, and randomization was stratified between those who had not previously received drug treatment (n=34) and those receiving treatment (n=34). The primary endpoint was change in clinic, ambulatory and home blood pressure compared with placebo.

Daily dietary nitrate was associated with lower blood pressure measured by all three methods. The mean clinic blood pressure reduction was 7.7/2.4 mm Hg, with 95% confidence intervals of 3.6–11.8/0.0–4.9 and P<0.001 and P=0.050, respectively. The 24-hour ambulatory reduction was 7.7/5.2 mm Hg, with 95% confidence intervals of 4.1–11.2/2.7–7.7 and P<0.001 for both. Home blood pressure fell by 8.1/3.8 mm Hg, with 95% confidence intervals of 3.8–12.4/0.7–6.9 and P<0.001 and P<0.01, respectively; there was no evidence of tachyphylaxis over the four-week intervention.

After dietary nitrate consumption, endothelial function improved by approximately 20% (P<0.001), and arterial stiffness decreased by 0.59 m/s (0.24–0.93; P<0.01); neither changed after placebo. The intervention was well tolerated. The authors described this as the first evidence of durable blood pressure reduction from dietary nitrate supplementation in a relevant patient group. They suggested dietary nitrate could have a role as an affordable, readily available adjunctive treatment for hypertension. The study was funded by the British Heart Foundation. The trial was registered at http://www.clinicaltrials.gov under NCT01405898.