Oral Bacteria Levels May Help Detect Alzheimer’s Risk Early: Study

New Delhi: Amid a global rise in Alzheimer’s disease cases, researchers have discovered that bacterial composition in the mouth and on the tongue may indicate brain function decline and the risk of neurodegenerative diseases.

A study by the University of Exeter in the UK, published in PNAS Nexus, highlights the role of oral bacteria in cognitive health. While some bacteria were found to enhance memory and attention, others were associated with a higher likelihood of developing Alzheimer’s disease.

According to the researchers, harmful bacteria may impact brain health by directly entering the bloodstream and causing damage. Additionally, an imbalance between beneficial and harmful bacteria could interfere with the conversion of dietary nitrate—found in vegetable-rich diets—into nitric oxide, a chemical essential for brain communication and memory formation.

Lead author Dr. Joanna L’Heureux from the University of Exeter Medical School emphasized the importance of routine bacterial testing during dental checkups to identify early signs of cognitive decline. “Our findings suggest that some bacteria might be detrimental to brain health as people age,” she noted.

The study involved 110 participants over the age of 50, recruited from an online brain health tracking study. Researchers analyzed mouth rinse samples to examine bacterial populations and their correlation with cognitive performance.

The results revealed that individuals with higher levels of Neisseria and Haemophilus bacteria demonstrated better memory, attention, and cognitive flexibility. These individuals also had higher levels of nitrite in their saliva, which is linked to better brain function.

Conversely, increased levels of Porphyromonas bacteria were more prevalent among individuals with memory issues. Another bacterial group, Prevotella, was associated with lower nitrite levels, which could indicate poorer brain health. Notably, this bacteria was more common in individuals carrying the Alzheimer’s risk gene, APOE4.

Professor Anne Corbett, also from the University of Exeter Medical School, suggested that these findings could pave the way for preventative strategies against dementia. She pointed to potential interventions such as dietary modifications, probiotics, improved oral hygiene, and targeted treatments.

This study reinforces the growing evidence linking oral health to brain health, underscoring the need for better dental care as a preventative measure against neurodegenerative diseases like Alzheimer’s.