A new study suggests that something as simple as beetroot juice could help older adults lower their blood pressure by reshaping the bacteria in their mouths.
The findings, published in Free Radical Biology and Medicine, show that dietary nitrate found in beetroot triggers shifts in the oral microbiome that improve nitric oxide pathways, a key factor in cardiovascular health.
Researchers conducted a placebo-controlled, double-masked crossover trial with 39 young adults aged 18–30 and 36 older adults aged 67–79. Participants drank either nitrate-rich beetroot juice, a nitrate-free placebo juice, or used antiseptic mouthwash across separate two-week periods, with washout breaks in between.
The study found a clear contrast between younger and older adults. Older adults, who began with higher blood pressure readings, experienced a significant reduction in mean arterial pressure of about 4 mmHg on average when consuming nitrate-rich beetroot juice. Younger adults, however, showed no meaningful change.
Blood pressure improvement in the older group was tied to changes in oral bacteria. Specifically, beetroot juice consumption was associated with a decrease in a Prevotella-dominated bacterial group.
This shift was strongly linked to higher plasma nitrite levels and lower blood pressure. In contrast, increases in nitrate-reducing bacteria like Neisseria and Rothia were also observed, with older adults showing a greater response than the younger participants.
The mouthwash treatment highlighted how sensitive this process is to oral bacteria. Antiseptic mouthwash reduced microbial diversity and, in younger participants, even impaired vascular function. By disrupting the microbiome, it blocked the normal conversion of dietary nitrate to nitrite, interfering with nitric oxide production.
Nitric oxide is a vital signaling molecule that helps blood vessels relax and maintain healthy blood pressure. The body’s natural ability to produce it declines with age, which is one reason older adults face higher risks of hypertension and heart disease. The study points to dietary nitrate as a natural “backup” system for restoring this pathway.
Researchers emphasized that the blood pressure benefits were not linked to changes in arterial stiffness or endothelial function. Instead, they were driven by the microbiome shifts and nitrite availability. The findings suggest that nutrition, combined with maintaining oral bacterial balance, could offer a simple and safe way to support cardiovascular health as people age.
The research highlights how oral bacteria play a bigger role in overall health than once thought. For seniors, regularly drinking beetroot juice may offer a simple way to support heart health and reduce blood pressure.