Periodontal Disease Linked to Alzheimer’s Biomarker, Study Finds

New research out of NYU College of Dentistry and Weill Cornell Medicine “adds to the growing evidence of a connection between periodontal disease and Alzheimer’s” disease, Science Daily reports. The findings show the importance of the oral microbiome and may offer clues for preventing Alzheimer’s.

Researchers found that adults who have more harmful than healthy bacteria in their gums are more likely to have evidence for amyloid beta, a key biomarker for Alzheimer’s, in their cerebrospinal fluid (CSF). Amyloid beta is one of two characteristic proteins for Alzheimer’s in the brain. The other, tau, was not associated with an imbalance in oral bacteria.

The study, “Periodontal dysbiosis associates with reduced CSF A 42 in cognitively normal elderly” by Kamer et al., was published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.

“To our knowledge, this is the first study showing an association between the imbalanced bacterial community found under the gumline and a CSF biomarker of Alzheimer’s disease in cognitively normal older adults,” said Angela R. Kamer, the lead author on the study.

The study involved 48 healthy adults ages 65 and over. The researchers collected bacterial samples from under the gumline and CSF samples via a lumbar puncture to measure levels of amyloid beta and tau. The researchers then analyzed the bacterial samples to quantify “bad” bacteria — those known to be harmful to oral health — and “good bacteria” — those that are positive for oral health.

An imbalance in bacteria, with more harmful than good, was linked with an increased likelihood to have more amyloid beta in the brain. The reason, researchers speculated, could be that healthy oral bacteria may be protective against Alzheimer’s, in addition to maintaining bacterial balance in the mouth and decreasing inflammation.

“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,” said Kamer. “These findings suggest that multiple oral bacteria are involved in the expression of amyloid lesions.”

The researchers are planning to conduct a follow-up study to determine if improving gum health through deep oral cleanings could modify levels of beta amyloid in the brain and prevent Alzheimer’s disease.

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