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“Beet juice may help lower blood pressure, but new research shows that its effectiveness depends on your age and the bacteria living in your mouth.” Scientists have found that the microbes living on the tongue are essential for converting the dietary nitrate in beets into nitric oxide—a compound that supports healthy blood flow, heart function, and physical performance. However, the benefits of this conversion vary significantly between younger and older adults, revealing a previously unrecognized connection between age, the oral microbiome, and vascular health.
Beet Juice Study Reveals Age-Linked Differences in Blood Pressure and Oral Microbiome Response
Researchers at the University of Exeter explored how dietary nitrate interacts with the oral microbiome and whether age influences its effectiveness. They began by analyzing a larger group of 75 participants aged either 18–30 or 67–79, then selected a focused subgroup of 26 (13 aged 18–22 and 13 aged 70–79) for in-depth crossover testing. This group drank nitrate-rich beet juice so scientists could study its impact on blood pressure and oral bacteria across different ages. “Many people praise beets as a nutrient-packed superfood for managing high blood pressure, but this study reveals that age can significantly influence their vascular benefits.”
But what role does the mouth play in all of this? Unlike many nutrients that are digested and absorbed in the gut, nitrate—found in vegetables like beets, spinach, arugula, and lettuce—follows a different path. Once consumed, nitrate enters the bloodstream, and about 25% is redirected to the salivary glands. From there, it mixes with saliva and is processed by bacteria living on the tongue, which convert it into nitrite. This nitrite is then swallowed and transformed into nitric oxide as it moves through low-oxygen areas of the digestive tract.
Nitric oxide, the end product of this process, is a gas that plays a vital role in regulating blood flow, lowering blood pressure, supporting immune function, and enhancing brain activity. It also helps blood vessels relax and expand, easing cardiovascular strain and improving circulation. Additionally, it boosts the efficiency of oxygen use in muscles during physical activity. While the body can produce nitric oxide on its own, this production declines with age, stress, and illness—making dietary nitrate sources like beets increasingly valuable as we get older.
Crucially, the first step of this process converting nitrate into nitrite relies on the oral microbiome.
Triple-Trial Experiment Tests How Beet Juice and Oral Bacteria Influence Vascular Health
In the study, 26 healthy volunteers completed three separate 10-day trials: one with nitrate-rich beet juice, one with nitrate-depleted beet juice (placebo), and one with nitrate-rich juice combined with antiseptic mouthwash, which disrupts oral bacteria. Before and after each phase, researchers collected blood samples, tongue swabs, and vascular health data to track the impact.
The researchers discovered that, after consuming beet juice, the older participants experienced a notable drop in both their 24-hour systolic and diastolic blood pressure. In addition, their tongue microbiome shifted: levels of nitrate-reducing bacteria such as Veillonella increased, while Actinomyces and Neisseria declined. “Although Actinomyces doesn’t usually metabolize nitrate, Neisseria does—indicating that these microbial shifts may reflect broader age-related adaptations or compensatory responses within the oral microbiome
In the younger group, researchers found that beet juice had no meaningful effect on blood pressure, and the changes in tongue bacteria didn’t favor an increase in nitrate-processing microbes. Although both younger and older participants showed higher levels of nitrate and nitrite in their blood, as well as elevated exhaled nitric oxide—indicating successful absorption—the actual health effects differed significantly between the age groups.
Mouthwash Disrupts Nitrate Processing, Nullifying Beet Juice Benefits in Older Adults
In the control group, where participants used antiseptic mouthwash to disrupt the oral microbiome, the older adults’ blood pressure remained unchanged from baseline—similar to the younger group. Their nitric oxide levels also dropped, implying that eliminating the tongue’s bacteria interfered with the body’s ability to process and utilize dietary nitrate effectively.
As expected, the placebo group, which consumed nitrate-depleted beet juice, showed no changes in blood pressure or oral microbiota composition.
“This study demonstrates that nitrate-rich foods can reshape the oral microbiome in ways that may reduce inflammation and lower blood pressure in older adults,” said co-author Andy Jones, a professor at the University of Exeter. “It opens the door for larger studies to examine how factors like lifestyle and sex may affect people’s responses to dietary nitrate.”
“Though the researchers conducted a short-term study with a small sample size and basic health measures like oral swabs and blood pressure readings, they uncovered new evidence that oral bacteria play a crucial, previously overlooked role in regulating key biological processes throughout the body.”
Findings Suggest Aging Mouths May Adapt by Hosting More Nitrate-Responsive Bacteria
The study also offers fresh insight into how the oral microbiome evolves with age. “For instance, as we age and rely more on our diet to support heart health, our mouths may naturally increase the presence of nitrate-responsive bacteria to help meet those demands.”
“We already know that diets rich in nitrate offer health benefits, and that older adults naturally produce less nitric oxide as they age,” said study author Anni Vanhatalo, a professor at the University of Exeter. “They’re also more likely to have higher blood pressure, which raises the risk of cardiovascular problems like heart attacks and strokes. Encouraging seniors to eat more nitrate-rich vegetables could bring substantial long-term health advantages.”
The study also highlights the importance of further research into age-related changes in the oral microbiome and supports the development of age-targeted interventions that leverage its potential—a system still largely unexplored, much like the gut microbiome. Interestingly, the microbial network in older adults that responded most significantly to dietary nitrate (referred to as MM6O) included bacterial species associated with chronic inflammation and immune dysfunction. Managing this group could have implications for conditions such as age-related cognitive decline and reduced infection resistance.
“This study is a strong example of how bioscience can illuminate the intricate relationships between nutrition, the microbiome, and healthy aging,” said Lee Beniston of the UK’s Biotechnology and Biological Sciences Research Council. “By showing how dietary nitrate influences oral bacteria and blood pressure in older adults, it paves the way for new nutritional strategies to support vascular health.”
Read the original article on: New Atlas
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