What your mouth has to do with your risk of dementia

“The more sensational story is whether it goes the other way around and people with poor oral health are more susceptible to dementia, particularly Alzheimer’s disease.”

It is, of course, possible that it goes both ways, he adds.

There are several theories about why poor oral health might increase the risk of dementia.

Bacteria may travel through the bloodstream to the brain, and they (or their byproducts) may cause an inflammatory response. There is, Brodaty explains, “quite a lot of inflammation” in the brains of people with Alzheimer’s disease.

Another theory is that the amyloid beta protein, which is the toxic protein that builds up in the brain in Alzheimer’s disease, may provide some protection against infection. When bacteria like porphyromonas gingivalis (the main pathogen in the gum disease periodontitis, which affects up to 62 per cent of adults) get into the brain, it may provoke more amyloid.

Finally, what we put in our mouths affects our risk of dementia both directly and indirectly.

Smoking, excessive alcohol, cholesterol, obesity, hypertension and diabetes are all among the 14 modifiable risk factors (the others are education, traumatic brain injury, depression, physical inactivity, hearing loss, air pollution, social isolation and loss of sight).

Research suggests that a Mediterranean-style diet rich in specific nutrients may protect the brain through anti-inflammatory and antioxidant properties. This style of diet focuses on fruits, vegetables, whole grains, legumes, fish and other seafood, unsaturated fats such as olive oils, and minimal amounts of red meat, eggs and sweets.

Though the association between our oral and cognitive health is likely multifactorial – dependent on age and genetics, for instance – and needs more research, it is a compelling reminder to care for our mouths and what goes in them.

Currently, more than 55 million people have dementia worldwide and about 10 million new cases are diagnosed each year.

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There is no good evidence that probiotics can improve our oral microbiome, and long-term use of mouthwash may negatively impact the oral microbiome. There is, however, plenty that we can do.

The ADA recommends brushing twice daily with fluoridated toothpaste, flossing daily, eating a diet low in sugar, and having regular dental visits to care for your oral health.

“According to data from the ADA, shockingly, 74 per cent of Australians rarely or never floss, and only 55 per cent brush their teeth twice a day,” says Phoon-Nguyen. “One in four Australians have inflammation of the gums.”

If you have gum disease, such as periodontitis (symptoms include swollen or bleeding gums), Phoon-Nguyen’s advice is not to ignore it, as it can have long-term consequences on your health.

“Other ways you can also protect your oral and systemic health is making sure your medical conditions are managed (such as diabetes or heart conditions) and to stop smoking.”

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