Article Impact Level: HIGH Data Quality: STRONG Summary of Free Radical Biology and Medicine, S0891584925008068. https://doi.org/10.1016/j.freeradbiomed.2025.07.002 Dr. Anni Vanhatalo et al.
Points
- Nitrate-rich beetroot juice supplementation effectively lowered blood pressure in older adults, but this significant cardiovascular benefit was not observed in the younger study participants.
- The composition of the oral microbiome changed differently between young and older adults following a two-week nitrate intervention, highlighting an age-dependent microbial response to dietary changes.
- A decrease in the abundance of the oral bacteria genus Prevotella in older adults was strongly associated with an increase in plasma nitrite concentration.
- The blood pressure reduction in the older cohort correlated with this increase in plasma nitrite, suggesting an enhanced conversion of nitrate to beneficial nitric oxide.
- These findings suggest that the cardiovascular benefits of dietary nitrate in older adults are mediated by positive changes in the oral microbiome, specifically the suppression of certain bacteria.
Summary
A placebo-controlled, double-masked, crossover study investigated the effects of dietary nitrate and antiseptic mouthwash on the oral microbiome, nitric oxide bioavailability, and vascular function, comparing 39 young adults (18–30 years) and 36 older adults (67–79 years). Participants completed three 2-week interventions (placebo, nitrate-rich beetroot juice [BR], antiseptic mouthwash [MW]) separated by 2-week washouts. The study found that ageing modulates responsiveness to nitrate, with oral microbiomes of young and older adults responding differently to the BR intervention (P = 0.01), while remaining unaffected by placebo or mouthwash.
Older adults, who had a higher baseline mean arterial pressure (MAP) than the young (95 ± 9 mmHg vs. 87 ± 7 mmHg, P < 0.001), experienced a significant decrease in brachial MAP after the BR intervention (−4±4 mmHg, P = 0.003), an effect not seen in the young cohort. This reduction in blood pressure correlated with increased plasma nitrite concentration (change in central MAP vs. [NO2−] r = −0.41, P = 0.02). In contrast, flow-mediated dilatation (FMD) was unaffected in older adults, whereas young adults showed a difference in ΔFMD% changes between the MW and BR conditions (P = 0.04).
The increase in plasma nitrite, which contributed to the blood pressure benefit in older adults, was strongly correlated with a decrease in a co-occurring bacterial module dominated by the genus Prevotella. Specifically, strong negative correlations were found between plasma nitrite and P. intermedia (r = −0.72, P = 0.001), P. dentalis (r = −0.88, P < 0.0001), and Crassaminicella sp. SY095 (r = −0.81, P < 0.0001). The findings suggest that dietary nitrate enhances cardiovascular health in older individuals primarily by suppressing specific oral bacteria, thereby increasing nitric oxide bioavailability.
Link to the article: https://www.sciencedirect.com/science/article/pii/S0891584925008068
References Vanhatalo, A., L’Heureux, J. E., Black, M. I., Blackwell, J. R., Aizawa, K., Thompson, C., Williams, D. W., Van Der Giezen, M., Winyard, P. G., & Jones, A. M. (2025). Ageing modifies the oral microbiome, nitric oxide bioavailability and vascular responses to dietary nitrate supplementation. Free Radical Biology and Medicine, S0891584925008068. https://doi.org/10.1016/j.freeradbiomed.2025.07.002
