Effects of inorganic nitrate and beetroot supplementation on endothelial function: a systematic review and meta-analysis

Eur J Nutr. 2016 Mar;55(2):451-459. doi: 10.1007/s00394-015-0872-7. Epub 2015 Mar 13.


Background: Diets rich in inorganic nitrate are associated with lower blood pressure, an effect that may be mediated by an improvement of endothelial function (EF). Therefore, a systematic review and meta-analysis of randomised controlled trials (RCTs) were conducted to examine the effects of inorganic nitrate and beetroot supplementation on measures of EF.

Methods: MEDLINE, EMBASE and Scopus databases were searched from inception until November 2014. Specific inclusion criteria were as follows: (1) RCTs; (2) trials comparing inorganic nitrate or beetroot supplementation with placebo control groups; and (3) trials reporting effects of these interventions on outcomes of vascular function. Random-effect models were used to assess the pooled effect sizes showed as standardised mean differences (SMD).

Results: Nine crossover trials and three parallel trials met our inclusion criteria. The trials were conducted between 2008 and 2014 and included a total of 246 participants with 10-64 participants per study. The duration of each intervention ranged from 1.5 h to 28 days. Inorganic nitrate and beetroot consumption was associated with an improvement in vascular function (SMD 0.36; 95 % CI 0.16, 0.56; P < 0.001). The effect on EF was significantly associated with the dose of inorganic nitrate (β = 0.04, SE = 0.01, P < 0.001), age (β = -0.01, SE = 0.004, P = 0.02), baseline BMI (β = -0.04, SE = 0.02, P = 0.05) and systolic BP (β = -0.01, SE = 0.005, P = 0.02).

Conclusions: Inorganic nitrate and beetroot supplementation was associated with beneficial effects on EF. These effects appear to be reduced in older subjects and in subjects with greater cardiometabolic risk.

Keywords: Beetroot; Cardiovascular risk; Endothelial function; Flow-mediated dilation; Inorganic nitrate; Meta-analysis.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Beta vulgaris / chemistry*
  • Blood Pressure / drug effects
  • Body Mass Index
  • Cardiovascular Diseases / prevention & control
  • Dietary Supplements*
  • Endothelium / drug effects*
  • Endothelium / metabolism
  • Humans
  • Metabolic Syndrome / prevention & control
  • Nitrates / administration & dosage*
  • Plant Roots / chemistry*
  • Randomized Controlled Trials as Topic
  • Risk Factors
  • Treatment Outcome


  • Nitrates