P4.24 DIETARY INORGANIC NITRATE LOWERS CENTRAL BLOOD PRESSURE

Abstract

Background: Dietary inorganic nitrate is reduced to (nitric oxide) NO in the body. Beetroot is a rich source of dietary inorganic nitrate and has been shown to lower brachial blood pressure (BP) by this mechanism. The effect on aortic (central) BP, which may be a better predictor of cardiovascular disease, has not been studied. Objectives: To measure the effect of dietary nitrate in beetroot juice on central BP at both 30 minutes and over a 6 hour period post-beetroot juice consumption. Method: A double-blind, randomised, placebo-controlled crossover trial was performed in nine healthy, normotensive men and women aged between 22 and 45 years. Participants were randomised to receive beetroot juice (6.5–7.3 mmol nitrate) or placebo juice (0.04–0.06 mmol nitrate). Brachial and central BP were measured at baseline, 30 and 60 minutes post-ingestion, and at least hourly for the following 24 hours. Following a washout period, the procedure was repeated within seven days with crossover to the opposite arm of the trial. There were no dietary restrictions during the study. Results: Compared with placebo, beetroot juice lowered central systolic BP at 30 minutes (change in beetroot juice: −2.6±3.4 mmHg vs. change in placebo: 1.8±5.9 mmHg, P=0.045). Beetroot juice also lowered central systolic BP averaged over 6 hours post-ingestion (beetroot: 106±8 mmHg vs. placebo: 111±11 mmHg, P=0.029). Conclusion: Consumption of beetroot juice lowered central BP. Beetroot juice could have a role in CV risk management in the general population, but further research is required to establish its long-term benefits, safety and tolerability.