A simple daily habit involving beetroot juice may help older adults improve their blood pressure, according to a new study from the University of Exeter.
Researchers discovered that drinking nitrate-rich beetroot juice twice a day for two weeks lowered blood pressure in older adults and also changed the types of bacteria living in their mouths.
The findings, published in the journal Free Radical Biology and Medicine, suggest that the tiny microbes inside the mouth may play a much bigger role in heart health than scientists once realized.
High blood pressure, also called hypertension, affects millions of people around the world. It increases the risk of heart attacks, strokes, kidney disease, and other serious health problems. Blood pressure often rises naturally with age because blood vessels become stiffer and less flexible over time.
Doctors usually recommend exercise, healthy eating, and medications to control blood pressure. However, scientists are increasingly studying how nutrition and the body’s microbiome may also influence cardiovascular health.
The microbiome refers to the huge community of bacteria and other microbes living inside the body. Most people think about gut bacteria, but the mouth also contains many important microbes that affect health.
The new study focused on nitrate, a natural compound found in vegetables. Beetroot contains especially high amounts of nitrate, but spinach, kale, celery, fennel, and arugula are also rich sources.
When people eat nitrate-rich foods, certain mouth bacteria help convert nitrate into compounds that allow the body to make nitric oxide. Nitric oxide is very important because it helps blood vessels relax and widen, improving blood flow and lowering blood pressure.
Scientists already knew nitric oxide production tends to decrease with age. This reduction may partly explain why older adults are more likely to develop hypertension and cardiovascular disease.
Researchers wanted to see whether beetroot juice could influence the mouth microbiome in ways that improve nitric oxide production and blood vessel function.
The study included 39 adults younger than 30 years old and 36 adults in their 60s and 70s. Participants completed two separate testing periods lasting two weeks each.
During one phase, participants drank nitrate-rich beetroot juice every day. During the other phase, they drank a placebo version of the juice that looked and tasted similar but had the nitrate removed.
A two-week break separated the two phases to allow the body to return to normal before starting the second drink.
Researchers collected mouth samples and used bacterial gene sequencing to examine changes in oral bacteria before and after each phase.
The results showed that beetroot juice changed the oral microbiome in both younger and older adults, but the effects were especially important in the older group.
Among older participants, beetroot juice reduced levels of Prevotella, a type of bacteria researchers considered potentially harmful in this context. At the same time, the juice increased levels of Neisseria, bacteria associated with healthier nitric oxide production.
Most importantly, older adults experienced lower blood pressure after drinking the nitrate-rich beetroot juice. This improvement did not occur after drinking the placebo juice.
Younger adults did not show the same blood pressure benefit, likely because they already had healthier blood pressure and better natural nitric oxide production.
Professor Anni Vanhatalo from the University of Exeter explained that older adults naturally produce less nitric oxide as they age, which may make them more responsive to nitrate-rich foods.
She noted that increasing intake of nitrate-rich vegetables may offer important long-term cardiovascular benefits for older adults.
The findings suggest that beetroot juice works not only because of its nutrients but also because it changes the balance of bacteria inside the mouth.
The study also supports a growing body of research linking oral bacteria to heart health. Scientists now believe the mouth may be one of the key control centers for how the body processes nitrate.
Follow-up research has produced similar findings. One 2025 study involving older adults with treated high blood pressure found that nitrate-rich beetroot juice increased beneficial mouth bacteria such as Neisseria while decreasing other bacteria.
Another 2026 pilot study found that antiseptic mouthwash disrupted nitrate processing and reduced nitric oxide production. Researchers believe some antibacterial mouth rinses may accidentally harm the beneficial bacteria needed for healthy blood vessel function.
Animal research has also shown that mouth rinses supporting nitrate-processing bacteria may help lower blood pressure compared with strong antiseptic treatments.
Together, these studies suggest that oral bacteria may strongly influence how well nitrate-rich foods work in the body.
The researchers emphasized that beetroot juice is not meant to replace blood pressure medications or medical treatment. However, nitrate-rich vegetables may become an important addition to heart-healthy lifestyles, especially for older adults.
The findings also highlight how personalized nutrition may become more important in the future. Two people may eat the same foods but experience different benefits depending on the types of bacteria living in their mouths.
The researchers believe larger studies are now needed to understand how age, sex, diet, oral hygiene, medications, and microbiome differences influence responses to nitrate-rich foods.
Reviewing the findings carefully, the study appears strong because it used a placebo-controlled crossover design, meaning participants served as their own comparisons during different phases.
The use of bacterial gene sequencing also gave researchers a detailed view of how the oral microbiome changed. However, the study was still relatively small and lasted only two weeks, so it cannot prove long-term effects.
In addition, blood pressure improvements were mainly seen in older adults, meaning the results may not apply equally to younger people.
Still, the research provides important new evidence that oral bacteria may play a major role in healthy aging and blood pressure control, and it supports growing interest in nutrition-based approaches to cardiovascular health.
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