The Study
Ageing modifies the oral microbiome, nitric oxide bioavailability and vascular responses to dietary nitrate supplementation.
This study gave people special beetroot juice and mouthwash to see what happened to their blood pressure and mouth bacteria. It found that older people’s blood pressure went down after the juice, and their mouth bacteria changed in a way that matched the drop. But it didn’t prove the bacteria caused the drop—it just showed they changed together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Your mouth has tiny bacteria that turn nitrate from beetroot into nitric oxide, which helps relax blood vessels. But some bad bacteria in older people’s mouths make ammonia instead — and beetroot juice kills those bad bugs.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 576 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1A 4 mmHg drop in blood pressure is clinically meaningful — it’s similar to the effect of some blood pressure medications and reduces heart disease risk.
- 2In older adults (67–79), drinking beetroot juice daily for 2 weeks lowered blood pressure by 4 mmHg and raised nitrite levels.
- 3In young adults (18–30), nitrite went up but blood pressure didn’t drop.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Free radical biology & medicine
Year
2025
Authors
A. Vanhatalo, Joanna E L'Heureux, Matthew I. Black, Jamie R. Blackwell, Kuni Aizawa, Christopher Thompson, David W. Williams, Mark van der Giezen, P. Winyard, Andrew M. Jones
Related Content
Claims (7)
Nitrate from food is converted to nitrite by bacteria in the mouth, and that nitrite is then turned into nitric oxide in the bloodstream.
In healthy young adults aged 18–30, consuming dietary nitrate increases plasma nitrite but does not lower blood pressure, because their blood vessels already maintain optimal nitric oxide levels and do not respond further to additional nitrate.
Using Listerine® mouthwash for two weeks does not change blood nitrite levels or blood pressure in healthy young or older adults, even though it reduces the variety of bacteria in the mouth of young adults, showing that the mouthwash does not broadly affect bacteria that convert nitrate to nitrite.
In healthy older adults, dietary nitrate leads to a measurable decrease in specific oral bacteria that produce ammonia and a corresponding increase in plasma nitrite and lower blood pressure, compared to healthy young adults.
In healthy older adults with high blood pressure, drinking nitrate-rich beetroot juice daily for two weeks lowers central arterial pressure by about 4 mmHg due to increased plasma nitrite and reduced activity of oral bacteria that produce ammonia from nitrate, which increases nitric oxide availability and improves blood vessel function.
Drinking beetroot juice with all nitrate removed still raises nitrate levels in the blood of young and older adults, showing that other compounds in beetroot juice affect how the body handles nitrate.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.