Clean teeth could keep Alzheimer's at bay

Staying on top of oral health could prevent neurodegenerative diseases

Anna Sharratt 2 minute read February 7, 2020

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You’ve likely been told by your dentist – and not in a nice way – that you should floss more to prevent gum disease. During regular cleanings, mine likes to patronizingly, and rather aggressively, weave a piece of floss between my teeth, implying I don’t know how to do it myself.

But while you may know that bacteria between your teeth can lead to tooth decay, gum disease and bad breath, new research makes a much more sinister connection. The bacteria that cause gum disease may raise the risk of Alzheimer’s Disease, a serious neurological condition that leads to dementia, problems with memory, cognition and behavior.

Research on this is growing. Scientists in one 2019 study, published in the journal Science Advances, found Porphyromonas gingivali, one pathogen that causes gingivitis and periodontitis, in the brains of Alzheimer’s patients. Researchers believe that this bacterium releases toxic elements that encourage the abnormal growth of tau, a protein that interferes with how neurons function in the brain.

“While the connection between disruptions in the normal healthy oral bacteria and infections in the mouth seem obvious to a lot of us, envisioning a link between microorganisms in the mouth and a neurodegenerative disease such as Alzheimer’s Disease may seem a bit far-fetched,” says Dr. Dilani Senadheera, former assistant professor, Faculty of Dentistry at the University of Toronto and now a research assistant professor at Stony Brook University in New York.

However, she says, there is growing evidence that bacteria implicated in periodontal disease can increase blood levels of C-reactive protein, which causes inflammation in the body.

“It is also possible that the damage to neurons in the brain is caused by the direct invasion of the brain by periodontal pathogens present in dental plaque,” she says. In other words, the bad bacteria might travel.

Researchers are now looking at ways of controlling these bacteria, once they’re established and destructive.

What’s the take-away for the average non-flosser? “Practice regular oral hygiene,” says Dr. Senadheera. And visit a dentist regularly to stay on top of gum disease. She says that catching it when it’s at the gingivitis stage — when your gums are red and irritated — is critical. Waiting until you have bone erosion, excessive bleeding from the gums and tooth loss ­— also known as periodontal disease — is too late.

“People always ignore the mouth,” says Dr. Senadheera. But the implications of these microbes travelling to other areas of the body and inflicting damage are huge.”

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