Emerging research suggests that the bacteria living on the tongue and gums may influence brain health and cognitive decline. Scientists are uncovering surprising connections between the oral microbiome the ecosystem of bacteria in the mouth and how the brain functions as people age. Some bacteria may support memory and thinking skills, while others could serve as early warning signs of brain function decline.
This raises the possibility that diet and treatments that alter oral bacteria could help preserve brain health.
A recent study analyzed saliva samples from 115 adults over the age of 50. Among them, 52% had healthy brain function, while the remaining 48% showed early signs of cognitive decline. The study identified specific bacteria that were associated with better brain function. People with higher levels of Neisseria and Haemophilus bacteria performed better on cognitive tests, including memory, attention, and complex tasks.
Additionally, those with these bacteria had higher levels of nitrite in their mouths. Nitrite is produced when bacteria break down nitrate, which is found naturally in a vegetable-rich diet. This compound can be further converted into nitric oxide, which enhances circulation and blood flow to the brain. These findings suggest that consuming nitrate-rich foods, such as leafy greens like spinach and arugula, may promote the growth of beneficial bacteria and improve brain health.
Researchers are now exploring whether nitrate-rich beetroot juice can further enhance brain function in older adults by influencing bacteria in the mouth.
Conversely, other bacteria may contribute to cognitive decline. The study identified two groups of bacteria that were more common in people with memory problems. One, called Porphyromonas, is frequently linked to gum disease and was found in higher levels among individuals with cognitive impairment. Another group, Prevotella, was associated with lower nitrite levels and poorer brain function. Prevotella was also more prevalent in people who carry the APOE4 gene, a known risk factor for Alzheimer’s disease.
These findings suggest that certain bacteria may play a harmful role in brain aging. This also raises the possibility that routine dental checkups could include tests for specific bacteria as an early warning system for cognitive decline.
If some bacteria support brain health while others contribute to deterioration, then altering the balance of bacteria in the mouth could be a potential strategy for preventing dementia. Encouraging the growth of beneficial bacteria like Neisseria while reducing harmful ones such as Prevotella and Porphyromonas might help maintain brain function as people age. This could be achieved through dietary changes, probiotics, improved oral hygiene, or even targeted treatments designed to reshape the oral microbiome.
While research on the relationship between oral bacteria and brain health is still in its early stages, these findings provide strong support for further investigation. If future studies confirm the role of the oral microbiome in maintaining cognitive function, monitoring and modifying mouth bacteria could become an important strategy for detecting and potentially delaying dementia.
In the meantime, the best approach is to maintain good oral hygiene, visit the dentist regularly, and consume nitrate-rich foods like leafy greens to nourish beneficial bacteria in the mouth.
