Gingivitis & Alzheimer’s: What the Research Shows

Clinical Content Reviewed by Dr. Jay Khorsandi, DDS
Last Modified:

Table of Contents

  1. Alzheimer's & Gingivitis Connection
  2. Can Brushing Prevent Alzheimer's
  3. What Is Gingivitis
  4. Gingivitis Symptoms & Indications
  5. Alzheimer's Disease
  6. The Bottom Line
  7. References

Studies have found a connection between the bacteria caused by gingivitis (gum disease) and the development of Alzheimer’s disease.

Scientists are split between how much this suggests that gingivitis is a factor in whether a person is likely to get Alzheimer’s, but there is broad consensus that this highlights the complex nature of Alzheimer’s as well as the enduring importance of good oral hygiene and regular dental checkups.

The Connection Between Alzheimer’s Disease and Gingivitis

Research has found that the inflammatory molecules produced by gum disease can make their way from infections in the mouth to the brain via the bloodstream. Some lab studies have suggested that this can potentially act as a catalyst for the development of dementia.

Another study found that older adults with the symptoms of gingivitis, as well as other mouth infections, were more likely to develop Alzheimer’s disease than those who had no such oral health problems.

On autopsies of adults ages 65 and up who were diagnosed with Alzheimer’s and who died for reasons related to the condition, doctors found antibodies against oral bacteria, specifically P. gingivalis. Researchers discovered that people who have harmful levels of gum bacteria were also more likely to have a protein marker for Alzheimer’s disease in their cerebrospinal fluid, meaning that there is an association between the imbalanced bacteria levels in the gum and the genetic likelihood for developing Alzheimer’s.

Alzheimer’s disease is marked by two proteins in the brain. The researchers looked at DNA in bacterial samples taken from participants’ gums as well as a lumbar puncture to obtain cerebrospinal fluid to test for the presence of the two proteins.

Can Brushing Prevent Alzheimer’s Disease?

The study concluded that lower levels of harmful bacteria can maintain the necessary balance with healthy bacteria. This can decrease inflammation in the gums, which in turn might protect against the development of Alzheimer’s.

It is not yet known if deep dental cleanings to remove accumulated plaque and tartar from the gums to modify the brain proteins could outright prevent Alzheimer’s disease, but this is an area that scientists are looking at.

Other scientists have urged caution and not to assume that there is a causative link between gum disease and Alzheimer’s. Dementia is a very complex disease, and there is more to its development than simply having bad oral health — as important as oral health is and as much as oral health impacts the rest of the body.

What Is Gingivitis?

Gingivitis is a condition where the gums are inflamed, usually due to an accumulation of bacteria (called plaque) on the surface of the teeth. Gingivitis is a non-destructive disease, but if it is not treated, it can cause periodontitis. This is a full-on form of gum disease where the gums retreat completely from the teeth, which can cause the teeth to fall out.

There are different causes of gingivitis, but the most common is that too much plaque builds up between and around the teeth. When in excess, the plaque causes an automatic immune response that works against the gingival (gum) tissue.

Other causes of gingivitis include changes in hormones, especially during pregnancy, the menstrual cycle, menopause, and even puberty. The gingiva is known to become more sensitive during hormonal changes, and is more susceptible to inflammation.

Cancer, HIV, and diabetes have been connected with a higher degree of gingivitis. Medications can affect oral health, especially those where saliva flow is impeded. Less saliva means plaque has a greater chance of building up.

Smoking has also been positively linked to gum disease. Bad diet, like not having enough vitamin C, contributes to gum disease.

Gingivitis is more common as a person grows older.

Lastly, a family history of gingivitis is also a predictor for the condition. Patients who have at least one parent with the disease will likely get it themselves.

Roughly 70% of adults aged 65 and older have gum disease, including chronic and systemic inflammation.

Gingivitis Symptoms & Indications

Signs and symptoms of gingivitis include:

  • Discolored gums (bright red or purple).

  • Bad breath.

  • Tender gums that are sensitive to touch.

  • Bleeding gums when flossing or brushing.

Mild cases of gingivitis might not have any symptoms, but the condition can still develop into periodontitis. Regular dental visits should help a dentist catch gingivitis even in its asymptomatic form.

Alzheimer’s Disease

Alzheimer’s disease is one of the most common forms of dementia. It is a progressive neurodegenerative condition, where a person’s mental functions decline to the point that their daily life is severely disrupted, and their quality of life is greatly reduced.

Specifically, Alzheimer’s disease affects a person’s memory as well as their ability to learn new information (like a new person’s name), make decisions and judgments, communicate with others, and carry out their daily business.

The condition is largely caused by bacteria and the loss of nerve connections in the brain, specifically the hippocampus, the region of the brain that is critical in the formation of memories. While Alzheimer’s can affect life memories (people’s names and their relationship to the patient), it can also affect basic memories, like how to go to the toilet, how to eat, and how to drive. As the disease progresses, it affects other parts of the brain. In its final stages, it can drastically shrink the size of the brain.

Alzheimer’s first develops as subtle memory loss and personality changes, which might not be immediately noticed or recognized as the onset of dementia. Symptoms tend to appear in the mid-60s, but there are rare forms of Alzheimer’s that develop as early as the mid-30s. Overall, Alzheimer’s is the most common cause of dementia in older adults.

People with Alzheimer’s become more anxious and agitated more easily. Other symptoms include loss of spatial abilities (judging sizes, shapes, and distances) as well as depression and apathy.

There is no cure for Alzheimer’s disease. Treatment options entail medication and lifestyle changes to address symptoms and to make patients as comfortable as possible as the disease progresses.

Even if all these symptoms occur together, it does not necessarily mean that a person has Alzheimer’s disease. A doctor will have to perform a complete examination to return a diagnosis of Alzheimer’s.

The Bottom Line

Neurologists point out that the connection between gingivitis and Alzheimer’s disease highlights how many things can play a factor in the latter. Continued research into the link will potentially provide insight into possible ways to slow the development of Alzheimer’s.

Disclaimer: This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to serve as dental or other professional health advice and is not intended to be used for diagnosis or treatment of any condition or symptom. You should consult a dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.