The scary connection between brushing your teeth and dementia

Brushing your teeth regularly just became a direr situation. According to a new study published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring. an abundance of certain oral bacteria may increase one’s risk of experiencing cognitive decline later in life.

The connection between gum bacteria and Alzheimer’s

Subgingival periodontal bacteria describes the line of bacteria attached to the teeth below the gum line. In the new report, the authors were able to establish a strong correlation between its presence and the build-up of amyloid proteins associated with Alzheimer’s in cerebrospinal fluid (CSF) in the brain.

Harmful oral bacteria were identified as Prevotella, Porphyromonas, and Fretibacterium.

“To our knowledge, this is the first report of an association between subgingival periodontal bacteria and CSF biomarkers of AD pathology in cognitively normal elderly people. We found that subgingival periodontal dysbiosis characterized by increases in periodontal‐associated bacteria and decreases in health‐related bacteria associated with reduced CSF Aβ42 but not with CSF P‐tau,” the authors wrote in the paper.

“Our results show the importance of the overall oral microbiome – not only of the role of ‘bad’ bacteria, but also ‘good’ bacteria – in modulating amyloid levels. These findings suggest that multiple oral bacteria are involved in the expression of amyloid lesions.”

The researchers recruited 48 participants over the age of 65, with no prior history of cognitive illness. Each had their CSF levels of amyloid measured alongside bacterial samples taken from under the gums.

“Our sample is quite homogeneous composed of cognitively normal, educated, with good systemic health and oral habits. All medical, neuropsychological, imaging, CSF collection and dental exams were standardized. One trained periodontist performed all periodontal evaluations blind to CSF collection,” the authors added.

Follow-up analysis revealed that participants with higher levels of amyloid deposits in the brain were more likely to evidence a gum bacteria imbalance in their mouths. So it was less about the number of harmful bacteria and more about its disproportion compared to helpful bacteria.

“The mechanisms by which levels of brain amyloid accumulate and are associated with Alzheimer’s pathology are complex and only partially understood,” the authors continued.

“The present study adds support to the understanding that proinflammatory diseases disrupt the clearance of amyloid from the brain, as retention of amyloid in the brain can be estimated from CSF levels.”

It should be noted, that 42% of the sample carried a gene expression linked to the development of AD. Moreover, given the relatively small size of the study sample and the number of variables at play, no causal link could be established.

From the report:

“In conclusion, we showed that measures of periodontal bacterial dysbiosis were associated with lower CSF biomarkers of amyloidosis. Of additional importance, our results point to both pathogenic and healthy bacteria in modulating CSF Aβ42 levels. Periodontal dysbiosis can be changed with treatment, thereby offering hope that Aβ accumulation may be prevented, slowed, or even reversed.”