Limited evidence. Direction: Benefit.
C LimitedShort-term only
Rubric condition met: Meta-analyses of RCTs with a consistent direction and high heterogeneity (I2 = 98.2% in the 2026 analysis), but every pooled estimate mixes healthy adults with older or higher-risk adults and none reports a healthy-only estimate, so the grade is capped at C
A meta-analysis of 12 RCTs (246 adults, 1.5 hours to 28 days) found improved vascular function (SMD 0.36), smaller in older people and those with greater cardiometabolic risk. Two further meta-analyses found higher flow-mediated dilation (0.59% and 1.48%), the second with very high heterogeneity, and a dose-response analysis found 0.30% more per mmol of nitrate in the medium term. These analyses pooled healthy adults with older and higher-risk adults and gave no estimate for healthy adults alone. Trials were short and few.
| Study | Year | Design | Participants | Result |
|---|---|---|---|---|
| Lara 2016 | 2016 | meta-analysis | 246 | result not recorded |
| Jackson 2018 | 2018 | systematic review | not recorded | result not recorded |
| Norouzzadeh 2025 | 2025 | meta-analysis | 1823 | result not recorded |
| Celik 2026 | 2026 | meta-analysis | not recorded | result not recorded |
Celik B, Muriuki E, Kuhnle GGC. The Impact of Inorganic Nitrate on Endothelial Function: A Systematic Review of Randomized Controlled Trials and Meta-analysis Nutr Rev, 2026. PMID 40679494
Lara J, Ashor AW, Oggioni C. Effects of inorganic nitrate and beetroot supplementation on endothelial function: a systematic review and meta-analysis Eur J Nutr, 2016. PMID 25764393
Norouzzadeh M, Hasan Rashedi M, Ghaemi S. Plasma nitrate, dietary nitrate, blood pressure, and vascular health biomarkers: a GRADE-Assessed systematic review and dose-response meta-analysis of randomized controlled trials Nutr J, 2025. PMID 40128734
Jackson JK, Patterson AJ, MacDonald-Wicks LK. The role of inorganic nitrate and nitrite in cardiovascular disease risk factors: a systematic review and meta-analysis of human evidence Nutr Rev, 2018. PMID 29506204
Search (): (nitrate[ti] OR beetroot[ti]) AND ("flow-mediated"[tiab] OR "endothelial function"[tiab] OR "arterial stiffness"[tiab]) AND (meta-analysis[pt] OR systematic review[pt])
