Tongue microbiome may be associated with cognitive performance in aging
Scientists examined whether oral bacteria involved in converting dietary nitrate to nitrite are linked to cognitive function. In a study of younger and older adults in Exeter and Brussels, participants completed memory, processing speed, and focus tests, and provided tongue swabs plus blood and saliva samples. The findings suggest an association between tongue microbial composition and how well the brain performs cognitive tasks as people age.
Researchers compared 30 participants in Exeter and 30 in Brussels—half younger, half older—using ten cognitive tasks plus tongue, blood, and saliva samples. DNA sequencing identified oral bacteria, and results were matched to memory, speed, and focus scores.
Higher Prevotella histicola appeared alongside quicker reactions in both nations. Haemophilus parainfluenzae showed country-specific and task-specific patterns. Seventeen species varied by age; Neisseria flavescens was more common in younger adults but not directly tied to test results. Location was the sole significant predictor of microbial differences.
This research may shape how aging populations view oral hygiene, diet, and brain health. Older adults, caregivers, dentists, and clinicians could consider mouth bacteria as one factor among many in cognitive aging. If confirmed, simple tongue sampling might someday complement cognitive screening, though it cannot prove cause or replace established assessments. Public health messaging may emphasize oral care, but individual risk remains complex and influenced by location, age, and other unmeasured factors.