Dietary nitrate lowers ambulatory blood pressure in treated, uncontrolled hypertension: a 7d, double-blind, randomized, placebo-controlled, crossover trial

Abstract

Dietary nitrate has been shown to increase nitrate/nitrite levels and decrease blood pressure (BP) in multiple populations. There are few reports among hypertensives and these reports have provided conflicting evidence. We aimed to assess the effect of daily nitrate compared to placebo in subjects with uncontrolled hypertension.

On day 0, hypertensives wore an ambulatory BP monitor (ABPM) for 24h and blood was taken. Subjects were then randomized to 7d nitrate-rich beetroot juice (12.9mmol nitrate) followed by 7d nitrate-depleted beetroot juice (0.5mmol nitrate) or vice versa. ABPM and blood was assessed before and after both conditions.

20 subjects with treated yet uncontrolled hypertension entered and completed the trial (mean age = 62.5y, mean BMI = 30.7kg/m2). Baseline BP was 137/80 ± 7/7mmHg. Dietary nitrate was well tolerated and resulted in significantly increased plasma nitrite (p=0.0004) and decreased 24h SBP and DBP compared to placebo (-8mmHg; p =0.012 and -4mmHg; p=0.018 respectively).

Our results support the existing data suggesting an anti-hypertensive effect of dietary nitrate in treated yet uncontrolled hypertensives. Targeted dietary strategies appear promising contributors to BP control.