Looking for yet another reason to take care of those gums and pearly whites?

More research linking gum disease with Alzheimer’s disease will have you running to your bathroom for your toothbrush and dental floss in no time flat.

What’s the story behind this correlation? Let’s dig further into this surprising topic…

Like other parts of your body, the mouth is home to harmful bacteria that promote inflammation, as well as healthy, protective bacteria. The harmful bacteria can lead to gum disease.

Gum disease, or more specifically periodontal disease, is a huge concern for older people. In fact, the Centers for Disease Control (CDC) reports that 70 percent of Americans 65 and older have chronic gum disease.1

That’s very concerning because the latest study published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring by the New York University Dentistry School, found that bacteria which cause gingivitis (AKA gum disease) can travel from the mouth to the brain.2 (These results confirm the findings of numerous other studies.3)

How Does Gum Disease Start? 

According to the CDC, bacteria in the mouth infect tissue surrounding the tooth, causing inflammation, and opening the door to periodontal disease.

When bacteria stay on the teeth long enough, they form a film called plaque, which eventually hardens to tartar. This tartar build-up can spread below the gum line, which makes the teeth harder to clean.

When this occurs, all the fancy toothbrushes and floss can’t do much. At this point, only a dental health professional can remove the tartar and stop the periodontal disease process.

Oral Bacteria Trigger Alzheimer’s Disease 

In the study, researchers sought to prove the dental-mental wellness connection by taking both gum swabs and spinal tap samples from 48 cognitively healthy volunteers over 65 years of age.

First, they analyzed the DNA in gum swabs. Then, they performed a lumbar puncture to obtain cerebrospinal fluid and to determine levels of amyloid beta and tau proteins, which are both linked to the development of Alzheimer’s disease.

What did they find? Interestingly, the results showed that those with higher levels of healthy oral bacteria were more likely to have reduced amyloid levels in their spinal fluid. The investigators suggest that because high levels of healthy bacteria help maintain bacterial balance and decrease inflammation, they may help guard against Alzheimer’s.

On the flip side, researchers found that folks who have an abundance of harmful bacteria on their gum tissues may be at greater risk for dementia. The risk factor is that they are more apt to have a protein marker for Alzheimer’s disease, known as amyloid beta, in their cerebrospinal fluid (CSF).

“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 lead author Dr. Angela Kamer.4

She added, evidence of amyloid beta protein in the brain was associated with increased harmful bacteria and decreased beneficial bacteria.

Understanding Amyloid and Tau Proteins 

Amyloid beta lumps together to form plaques. Some experts believe that amyloid is the first protein deposited in the brain as Alzheimer’s develops. On the other hand, tau builds up in nerve cells and forms tangles and has also been linked to the development of Alzheimer’s disease. The evidence for tau is more impressive than the evidence for amyloid.

Senior study author Dr. Mony de Leon admits there’s still much more to learn about the origins of this disease.

“The mechanisms by which levels of brain amyloid accumulate and are associated with Alzheimer’s pathology are complex and only partially understood,” Dr. de Leon said.

He noted that amyloid changes are often observed decades before tau pathology or Alzheimer’s symptoms are detected.

“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,” Dr. Kramer said.

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

It’s important to note that this isn’t the first study to explore the dental-mental connection.

A 2019 National Institutes of Health study published in the Journal of Alzheimer’s Disease shows that the bacteria that causes gingivitis, the earliest form of periodontal disease, is also connected to several forms of dementia.5

The analysis revealed that older adults with signs of gum disease and mouth infections at the beginning of the study were more likely to develop Alzheimer’s during the study period. In fact, among those 65 years or older, both Alzheimer’s diagnoses and deaths were associated with the presence of antibodies that work against the oral bacterium P. gingivalis, a cause of gingivitis.

But what happens if one undergoes deep cleaning to remove stubborn deposits of plaque and tartar from under the gumline? Can this prevent Alzheimer’s? The authors report that they can’t say for sure and additional long-term study is warranted.

My Takeaway 

When it comes to the potential onset of Alzheimer’s disease there are plenty of things that are out of our control. On the other hand, dental hygiene is a modifiable risk factor for dementia. In other words, you can do something about it, and you should!

Along with regular dental appointments, brushing, flossing and a germ-killing mouthwash should all be part of your repertoire for good dental and mental health.


  1. https://www.cdc.gov/oralhealth/conditions/periodontal-disease.html 
  2. https://doi.org/10.1002/dad2.12172 
  3. https://advances.sciencemag.org/content/5/1/eaau3333 
  4. https://www.nyu.edu/about/news-publications/news/2021/april/gum-bacteria-alzheimers.html 
  5. https://www.nia.nih.gov/news/large-study-links-gum-disease-dementia 

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