Growing up, I was always told that oral health related directly to regular health. But now, a study from researchers at the NYU College of Dentistry and Weill Cornell Medicine has explained how important oral health actually is. According to Medical XPress, researchers determined that an unhealthy balance of gum bacteria – more harmful bacteria than healthy bacteria – was linked to Alzheimer’s disease. In fact, patients with this imbalance were more likely to have less amyloid beta in their cerebrospinal fluid (CSF), suggesting greater neural accumulation. Since amyloid beta is considered a biomarker for Alzheimer’s, it is incredibly important to understand how and why this dysbiosis could cause this. Check out the full findings published in Alzheimer’s & Dementia: Diagnosis, Assessment, & Disease Monitoring. 

Gum Bacteria Research

Altogether, past research has linked the relationship between periodontal disease and Alzheimer’s disease. According to this recent article, periodontal disease affects an estimated 70% of people older than 65. In terms of the periodontal landscape, the article explains:

Up to 700 species colonize the subgingival biofilm; among them, several known periodontal bacterial species are enriched in [periodontal disease], including: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella spp, Porphyromonas endodontalis, and Fretibacterium fastidiosum. Other bacteria are enriched in periodontal health including species belonging to Rothia, Corynebacterium, Veillonella, Actinomyces, Streptococcus, and Capnocytophaga. Periodontal bacterial dysbiosis is often expressed as the balance between PerioD‐associated and health‐associated bacteria

The imbalance of gum bacteria occurs when the disease-associated and health-associated bacteria exist on different levels. This study, perhaps the first of its kind, suggests that too many harmful gum bacteria are associated with the development of amyloid beta in the brain.

The Study

Altogether, Alzheimer’s disease is typically characterized by the accumulation of amyloid beta, which forms plaques, and tau, which causes neurofibrillary tangles. Researchers believe that some of the inflammation and health-related issues associated with an imbalance of gum bacteria could prevent amyloid from being removed from the brain and body.

To determine this, researchers evaluated 48 healthy participants. All participants were 65 years old or older. During the study, researchers collected gum bacterial samples and also cerebrospinal fluid (via a lumbar puncture) to evaluate how the oral bacteria influenced or related to protein levels in CSF. Alzheimer’s disease causes high amounts of tau and low amounts of amyloid beta in CSF. Both of these relate to higher brain amyloid or neurofibrillary tangle levels.

After an evaluation of the samples, researchers discovered:

• Those with more harmful gum bacteria than healthy were more likely to have the biomarker signature of Alzheimer’s disease.
• Higher levels of healthy gum bacteria could lower inflammation, modulate amyloid levels, and confer protection.
• No connection seems to exist between healthy or harmful gum bacteria and tau expression.

In the future, researchers would like to explore whether deep and thorough periodontal cleanings could play a role in Alzheimer’s prevention.

Alzheimer’s Disease (AD)

Alzheimer’s disease is a progressive neurological disorder characterized by brain cell death and degeneration. It is also the most common cause of dementia, accounting for up to 80% of cases. Researchers believe that a combination of lifestyle and environmental factors, as well as genetics, causes Alzheimer’s disease. The risk also increases with age. Additional risk factors include past head trauma, a family history of Alzheimer’s disease, poor sleeping or exercise patterns, and being female. Typically, Alzheimer’s disease occurs in stages, with each stage growing progressively more severe. Signs and symptoms include:

• Memory loss
• Difficulty carrying out everyday tasks
• Confusion and/or disorientation
• Difficulty speaking, swallowing, or walking
• Changes in personality or behavior, such as aggression or depression
• Malnutrition and dehydration
• Frequent falls or fractures