The hypotensive impact of nitrate-rich beetroot juice in the elderly may be attributed to distinct alterations in their oral microbiome, as indicated by the largest study of its kind.

Researchers at the University of Exeter conducted a study, published in the journal Free Radical Biology and Medicine, comparing the responses of older persons to those of younger adults. Prior studies have demonstrated that a diet rich in nitrates can lower blood pressure, hence mitigating the risk of cardiovascular disease.

Nitrate is essential for the organism and is ingested as a natural component of a diet abundant in vegetables. Older persons who consumed a concentrated beetroot juice ‘shot’ twice daily for two weeks experienced a reduction in blood pressure, a phenomenon not observed in the younger cohort.

The recent study, supported by a BBSRC Industrial Partnership Award, demonstrates that this result was likely due to the inhibition of potentially detrimental bacteria in the oral cavity. An imbalance between advantageous and detrimental oral bacteria can diminish the conversion of nitrate, prevalent in vegetable-rich diets, to nitric oxide. Nitric oxide is essential for the proper functioning of blood vessels and the regulation of blood pressure.

Professor Anni Vanhatalo, the author of the study from the University of Exeter, stated: “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 enlisted 39 individuals under the age of 30 and 36 individuals in their 60s and 70s via the NIHR Exeter Clinical Research Facility. The trial received support from the Exeter Clinical Trials Unit. Each group had nitrate-rich beetroot juice for two weeks, followed by two weeks of a placebo version devoid of nitrate. Each condition was separated by a two-week “washout” interval for recalibration. To assess the amount of bacteria in the oral cavity before and throughout each condition, the researchers used a bacterial gene sequencing approach.

After consuming nitrate-rich beetroot juice, both groups showed notable changes in the composition of their oral microbiota; however, these changes differed across the younger and older cohorts.

After consuming nitrate-rich juice, the older population showed a marked decrease in the oral bacteria Prevotella and an increase in the growth of bacteria that promote health, like Neisseria. When the nitrate-rich beetroot juice was consumed, the older cohort’s high average blood pressure at the start of the research dropped, but not when the placebo supplement was given.

Co-author Professor Andy Jones from the University of Exeter stated: “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, stated:

“This research is a great example of how bioscience can help us better understand the complex links between diet, the microbiome and healthy ageing. 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.”

Original Publication
Authors: 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.
Journal: Free Radical Biology and Medicine
DOI: 10.1016/j.freeradbiomed.2025.07.002
Method of Research: Experimental study
Subject of Research: People
Article Title: Ageing modifies the oral microbiome, nitric oxide bioavailability and vascular responses to dietary nitrate supplementation
Article Publication Date: 23-Jul-2025