People with gum disease may have an increased risk of dementia, according to a new study.
Scientists took samples of cerebrospinal fluid – which surrounds the brain and spinal cord – and performed bacterial smears on the gums of volunteers.
It revealed that people with poor oral health also have higher amyloid beta levels, a dangerous protein found in the brains of Alzheimer’s patients.
Gum disease is a common condition that has several causes: poor oral hygiene, stress, age and smoking, all factors that increase a person’s risk.
The best way to prevent and treat gum disease, according to the NHS, is a good cleaning regimen, including brushing your teeth twice a day for two minutes, using a good quality toothpaste, flossing, and regular visits to the dentist.
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Gum disease is a common condition that has several causes: poor oral hygiene, stress, age and smoking, all factors that increase a person’s risk. People with the condition may be more at risk for dementia, a study claims
Beta amyloid proteins clump together in the brain to form plaques surrounding nerve cells, inhibiting brain function and causing cognitive decline.
But while there is a firm link between the protein and dementia, exactly how beta-amyloid causes the disease remains only partially understood.
A leading theory is that pro-inflammatory diseases, such as gum disease, prevent the body from flushing amyloid from the brain.
To study the link, American scientists took gum swabs and cerebrospinal fluid samples from 48 healthy volunteers, all over the age of 65.
People in this age group are at increased risk for both dementia and gum disease, with 70 percent of those over 65 suffering from the oral condition.


Scientists took samples of cerebrospinal fluid – which surrounds the brain and spinal cord – and performed bacterial smears on healthy volunteers. It revealed that people with poor oral health also have higher levels of amyloid beta, a protein found in the brains of Alzheimer’s patients.
The bacteria balance for all 48 people was compared to the levels of beta-amyloid and tau, another protein known to be present in dementia patients.
Scientists determined the level of ‘good’ bacteria, such as Corynebacterium and Actinomyces, and compared this to the presence of ‘bad’ bacteria, including Prevotella and Porphyromonas.
Data shows that individuals with more good bacteria than bad bacteria in their gums had lower amyloid levels in their cerebrospinal fluid, indicating that they are less at risk for dementia.
“ To our knowledge, this is the first study to show an association between the imbalanced bacterial community beneath the gum and a cerebrospinal fluid biomarker of Alzheimer’s disease in cognitively normal older adults, ” said Dr. Angela Kamer of New York University College of Dentistry and the lead author of the study.
‘The mouth is home to harmful bacteria that promote inflammation as well as healthy, protective bacteria.
“We found that having evidence for amyloid in the brain was associated with more harmful and decreased beneficial bacteria.”
The researchers speculate that having plenty of healthy bacteria in a person’s mouth can help fight inflammation and protect against Alzheimer’s.
“Our results demonstrate the importance of the overall oral microbiome – not just the role of ‘bad’ bacteria, but also ‘good’ bacteria – in modulating amyloid levels,” said Dr. Kamer.
“These findings suggest that multiple oral bacteria are involved in the expression of amyloid lesions.”
Researchers found no evidence of tau proteins in the samples taken from the participants, even if a person had high amyloid levels.
As a result, they cannot say whether tau lesions will develop in people with high amyloid levels or whether they will in fact continue to develop Alzheimer’s disease.
The researchers are now setting up a clinical trial to investigate whether improving gum health with a thorough cleaning can alter brain amyloid and prevent Alzheimer’s disease.
The study is published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring.