Link Between Tongue Bacteria and Cognitive Test Performance Uncovered by UK and Belgian Researchers

Exploring the Connection Between Tongue Microbes and Cognitive Abilities

According to НВ — Техно: A collaborative study conducted by scientists in the United Kingdom and Belgium has revealed a noteworthy statistical association between the bacterial communities residing on the tongue and cognitive test outcomes among 60 healthy adults. Published in the journal PLOS ONE, the research included equal groups of younger and older participants-15 from each country-with the younger group averaging around 20 years old and the older group ranging from 60 to 70 years. Age emerged as the most influential factor affecting cognitive performance.

Study Design and Key Findings

The investigation assessed multiple cognitive domains such as memory, attention, emotional recognition, and processing speed. Researchers also measured blood pressure and collected samples of blood, saliva, and tongue bacteria. Among the microbial species identified, Prevotella histicola was consistently linked to quicker responses on cognitive assessments across both populations. Conversely, Haemophilus parainfluenzae showed mixed associations: it correlated with better test scores in Belgian participants, but in the UK group, its influence varied depending on the specific cognitive task, showing both faster and slower responses.

Older adults demonstrated slower reaction times and lower scores on cognitive tests compared to younger participants. Differences in the abundance of 17 bacterial species were also observed between the age groups. Notably, older individuals had higher levels of bacteria from the genera Treponema and Tannerella, which have been linked to gum disease. In contrast, younger adults more frequently harbored bacteria capable of converting nitrates to nitrites, although the presence of these bacteria did not necessarily translate to superior cognitive performance.

The research team proposed that tongue bacteria might contribute to the production of nitric oxide, a compound known to dilate blood vessels, potentially influencing brain function. However, the study did not control for lifestyle factors such as diet, physical activity, or sleep, and compared distinct age groups rather than tracking changes within the same individuals over time. As a result, the findings do not establish a direct causal relationship between oral bacteria and cognitive abilities. Larger and more controlled studies are required to confirm these links.

This work sheds light on the intriguing potential role of the oral microbiome in cognitive health, emphasizing that the observed associations are complex and not necessarily cause-and-effect. Age remains the dominant factor shaping cognitive outcomes, suggesting that shifts in bacterial populations are one part of a multifaceted picture. Future research may clarify how specific bacterial species interact with neurological processes and whether targeting the oral microbiota could offer new strategies to enhance cognitive function across the lifespan.

The findings from the UK and Belgian researchers highlight the intricate connections between our microbiome and cognitive health, echoing similar insights from other studies. For instance, a recent investigation by UCLA has uncovered links between the gut microbiome and early signs of brain aging, suggesting that our body's microbial landscape may play a crucial role in mental decline. To explore this fascinating relationship further, you can read more about the gut-brain connection here.