Gum Disease-Causing Bacteria Linked To Higher Alzheimer's Disease Risk

The same bacteria causing gum disease has been linked to Alzheimer’s disease risk in a new study.

Also known as periodontitis and periodontal disease, gum disease happens because of a bacterial infection within the soft tissues in the mouth. Previous research linked periodontitis to kidney disease, diabetes, and even cardiovascular issues.

A new mouse study done by researchers from Tufts University has found a correlation between gum disease and Alzheimer’s disease through the bacteria Fusobacterium nucleatum (F. nucleatum).

With their findings published in the journal Frontiers in Aging Neuroscience, the team wanted to identify and characterize the association between periodontal disease induced by bacteria with Alzheimer’s disease.

Based on past research, F. nucleatum is not only commonly involved with periodontal disease but is also linked to colon cancer and oral cancer.

The researchers wondered how the bacteria commonly found in the mouth could exacerbate symptoms of a neurological condition like Alzheimer’s disease. Dr. Jake Jinkun Chen, a professor of periodontology and director of the Division of Oral Biology at Tufts University School of Dental Medicine and the study's lead author, said it can do two things.

“One, (it) generates inflammation both locally and systemically, which will affect the Alzheimer’s disease phenotype, as Alzheimer’s itself is an inflammatory disease. Two, it migrates and penetrates to the brain to colonize there and secrete pathological molecules to exacerbate the symptoms and signs of Alzheimer’s disease,” he explained.

To better understand this, Dr. Chen and his team used laboratory-cultured cells to show that the presence of F. nucleatum caused abnormal growth of microglial cells, which help remove any infection from the brain to keep the nervous system functioning. On top of the abnormal growth, the presence of the bacteria also led to an inflammatory response, which plays a role in the development of Alzheimer’s.

According to Dr. Chen, their research was crucial because the team targeted an “enormous health problem.”

A significant percentage of the adult population currently suffers from the periodontal disease worldwide, while Alzheimer’s is the most common type of dementia, with more than 55 million living with it globally, according to Alzheimer’s Disease International.

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