Beetroot juice changed oral bacteria in older adults, lowering blood pressure. The results highlight dietary nitrate as a potential tool for healthier aging.
The ability of nitrate-rich beetroot juice to lower blood pressure in older adults may be linked to measurable shifts in the community of bacteria living in the mouth, according to the largest study carried out to date on this topic.
The investigation, led by researchers at the University of Exeter and published in Free Radical Biology and Medicine, compared how younger and older participants responded to the juice. Earlier studies have already established that diets high in nitrate can help reduce blood pressure, an effect that plays an important role in lowering the likelihood of cardiovascular disease.
Nitrate’s role in the body
Nitrate plays an essential role in the body and is regularly consumed through vegetables as part of a healthy diet. In the study, older adults who drank a concentrated beetroot juice “shot” twice daily for two weeks experienced a drop in blood pressure. This effect, however, was not observed in the younger participants.
Funded by a BBSRC Industrial Partnership Award, the research suggests that the reduction in blood pressure may be linked to changes in oral bacteria. The findings indicate that beetroot juice suppressed certain harmful microbes in the mouth, helping to restore a healthier balance. When the balance tips toward harmful bacteria, the body’s ability to convert dietary nitrate (common in vegetables) into nitric oxide is reduced. Nitric oxide is vital for maintaining flexible, healthy blood vessels and plays a central role in blood pressure regulation.
Dietary recommendations for older adults
Study author Professor Anni Vanhatalo, of the University of Exeter, said: “We know that a nitrate-rich diet has health benefits, and older people produce less of their own nitric oxide as they age. They also tend to have higher blood pressure, which can be linked to cardiovascular complications like heart attack and stroke. Encouraging older adults to consume more nitrate-rich vegetables could have significant long-term health benefits. The good news is that if you don’t like beetroot, there are many nitrate-rich alternatives like spinach, rocket, fennel, celery, and kale.”
The research enrolled 39 participants under the age of 30 and 36 individuals in their 60s and 70s through the NIHR Exeter Clinical Research Facility, with additional support from the Exeter Clinical Trials Unit. Both age groups completed two separate two-week phases: one where they consumed nitrate-rich beetroot juice daily and another where they received a placebo version with the nitrate removed. Between these phases, each group observed a two-week “wash out” period to reset their systems. To evaluate the effects, the researchers used bacterial gene sequencing to identify which microbes were present in the participants’ mouths before and after each treatment phase.
Different effects by age group
In both groups, the make-up of the oral microbiome changed significantly after drinking the nitrate-rich beetroot juice, but these changes differed between the younger and older age groups.
The older age group experienced a notable decrease in the mouth bacteria Prevotella after drinking the nitrate rich juice, and an increase in the growth of bacteria known to benefit health such as Neisseria. The older group had higher average blood pressure at the start of the study, which fell after taking the nitrate-rich beetroot juice, but not after taking the placebo supplement.
Co-author Professor Andy Jones, of the University of Exeter, said: “This study shows that nitrate-rich foods alter the oral microbiome in a way that could result in less inflammation, as well as a lowering of blood pressure in older people. This paves the way for larger studies to explore the influence of lifestyle factors and biological sex in how people respond to dietary nitrate supplementation.”
Dr Lee Beniston FRSB, Associate Director for Industry Partnerships and Collaborative Research and Development at BBSRC, said: “This research is a great example of how bioscience can help us better understand the complex links between diet, the microbiome and healthy aging. By uncovering how dietary nitrate affects oral bacteria and blood pressure in older adults, the study opens up new opportunities for improving vascular health through nutrition. BBSRC is proud to have supported this innovative partnership between academic researchers and industry to advance knowledge with real-world benefits.”
Reference: “Ageing modifies the oral microbiome, nitric oxide bioavailability and vascular responses to dietary nitrate supplementation” by Anni Vanhatalo, Joanna E. L’Heureux, Matthew I. Black, Jamie R. Blackwell, Kuni Aizawa, Christopher Thompson, David W. Williams, Mark van der Giezen, Paul G. Winyard and Andrew M. Jones, 3 July 2025, Free Radical Biology and Medicine.
DOI: 10.1016/j.freeradbiomed.2025.07.002
Funded by a BBSRC Industrial Partnership Award
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