The bacteria living on your tongue might have something to do with how quickly you process information.
That unexpected possibility is emerging from research involving 60 healthy adults in the United Kingdom and Belgium. Scientists found that people with more of a certain type of tongue bacteria tended to respond faster during some tests of thinking and attention.
The findings, published October 5, 2026, in the journal PLOS One, suggest that the mouth and brain may be connected in ways researchers are only beginning to understand.
The study doesn’t prove that these bacteria make people think faster. However, it offers another reason for scientists to investigate how the tiny organisms living in our mouths interact with the rest of the body.
Your Tongue Is Home to More Than You Might Expect
Most people associate mouth bacteria with bad breath, cavities, or gum problems. But the mouth also contains microorganisms that participate in normal processes inside the body.
Researchers wanted to understand whether differences in these bacterial communities might be connected to how well people perform certain mental tasks.
They recruited 30 adults from Exeter, England, and 30 from Brussels, Belgium.
Each location included 15 younger adults and 15 older adults. Average ages across the younger groups ranged from approximately 23 to 26, while those in the older groups ranged from 62 to 71.
Participants provided tongue samples and completed 10 tests designed to measure different thinking skills, including recognizing information and responding to visual tasks.
One type of bacteria stood out.
People with higher levels of Prevotella histicola tended to respond faster during certain tests.
In the British group, the connection appeared during a task involving matching abstract shapes or patterns. In Belgium, it appeared during a task involving learning visual objects.
The connection wasn’t identical across both groups, which means researchers still need to establish how consistent the finding really is.
Still, the results suggest that differences in the bacteria living on our tongues may be linked to differences in how quickly we respond to information.
The Beetroot Connection Makes the Discovery More Interesting
One possible explanation involves something as ordinary as eating vegetables.
Foods such as beetroot and leafy greens contain natural compounds called nitrates.
After we eat these foods, some of the nitrate enters our saliva, where certain mouth bacteria help change it into nitrites. The body can then use that to produce nitric oxide, which helps blood vessels relax and supports blood circulation.
This matters because the brain depends on a steady supply of blood to function properly.
Scientists are investigating whether mouth bacteria might influence some aspects of brain performance through this process.
Previous research has already shown that oral bacteria play a role in how the body handles nitrates.
In one small experiment involving 19 healthy volunteers, researchers found that using a chlorhexidine antiseptic mouthwash for seven days reduced the mouth’s production of a nitrate-related substance by approximately 90%.
Participants also experienced small increases in blood pressure.
The findings showed that some mouth bacteria have a measurable role in blood-vessel health.
However, the experiment didn’t examine thinking or memory, so it couldn’t establish a brain benefit.
Does This Mean Eating Beetroot Could Make You Think Faster?
Not necessarily.
Although beetroot and other nitrate-rich foods are involved in the process researchers are investigating, studies haven’t consistently shown that consuming more nitrate improves thinking.
A review of 13 studies involving 297 adults found no clear overall improvement in cognitive performance from nitrate or nitrite supplements.
Another experiment, published in 2021, followed 30 adults between ages 70 and 80. After 10 days of nitrate supplementation, researchers observed changes in oral bacterial communities and fewer errors during sustained-attention testing.
However, participants didn’t demonstrate improvements in choice-reaction time, short-term memory, or performance on a Stroop test, which measures aspects of attention and cognitive control.
In 2024, another experiment involving 60 Swedish adolescents found that a high-nitrate breakfast affected measurements of oxygenation in the brain’s prefrontal region. Yet working-memory performance didn’t improve significantly compared with the other breakfast conditions.
These findings suggest that the relationship between food, mouth bacteria, and brain performance is more complicated than simply eating more of one vegetable.
Related: The Surprising Superfoods That Boost Energy and Mood
Other Mouth Bacteria May Play Different Roles
The researchers didn’t find the same connection with every type of bacteria.
Save this article
Enter your email address and we'll send it straight to your inbox.
Another species, Haemophilus parainfluenzae, showed conflicting results.
In Belgium, higher levels were linked to faster responses during an emotion-recognition test. In the British group, however, higher levels were associated with slower responses on that type of test.
Researchers also found that having a wider variety of bacteria in the mouth wasn’t consistently linked to better thinking.
These differences are important because they challenge the idea that mouth bacteria can simply be divided into helpful and harmful groups.
The effect of a particular species may depend on other microorganisms, a person’s health, or the mental task being measured.
With only 30 participants at each research location, larger studies will be needed to determine which findings hold up.
What Does This Mean for Your Brain as You Age?
Scientists have been investigating the relationship between oral health and cognitive decline for several years.
In 2025, researchers examined mouth bacteria in 115 adults, including people with mild cognitive impairment. They found connections between certain bacteria and performance on selected thinking tests.
However, neither that study nor the newer investigation established that mouth bacteria cause cognitive decline or protect against dementia.
The studies also didn’t demonstrate that increasing or removing a particular species would improve memory.
Responding quickly to a test isn’t necessarily the same as having better memory, stronger everyday thinking skills, or a lower risk of developing dementia.
The recent findings provide clues for future research rather than answers about preventing age-related brain changes.
Why Taking Care of Your Mouth Still Matters
Even without a proven connection to faster thinking, oral health deserves attention.
According to the Centers for Disease Control and Prevention, approximately 42% of American adults aged 30 and older had periodontitis, a serious form of gum disease, in data collected between 2009 and 2014.
Among adults aged 65 and older, the estimate was approximately 60%. Those numbers highlight how common gum problems are, particularly among older Americans.
However, they don’t mean gum disease causes dementia or that improving dental hygiene will make someone think faster.
The American Dental Association continues to recommend brushing twice daily with fluoride toothpaste and cleaning between teeth every day. The new findings aren’t a reason to stop using mouthwash, especially if a dentist has recommended or prescribed it.
Researchers haven’t demonstrated that avoiding mouthwash improves brain function, and different products serve different purposes.
Could a Simple Tongue Test Reveal Something About Brain Health Someday?
Researchers are interested in whether studying the bacteria inside the mouth could eventually provide useful information about changes in brain function.
However, we’re not at the point where a tongue swab can predict memory problems, measure brain aging, or determine someone’s risk of dementia.
The latest study involved just 60 healthy adults, and some of its findings differed between the two countries.
Scientists still need larger investigations to determine whether the connections are reliable and whether changing mouth bacteria would make any meaningful difference.
For now, the discovery highlights an intriguing possibility: The microorganisms living on our tongues may be connected to processes happening far beyond the mouth.
Would you change your daily oral-care routine if future research proved it could also benefit your brain?
