New research proves it to be true to an even greater extent: Gum disease can inhibit the body’s ability to fight off amyloid plaques—clumps of misfolded proteins that clog up the brain in Alzheimer’s disease patients, according to a new study out of Massachusetts.

Researchers studied mice with gum disease, and found that bacteria from their mouths made their way to the brains via lesions between their teeth and gums. The bacteria overstimulated the brain’s microglial cells, a type of white blood cell that would usually “digest” the plaques that lead to Alzheimer’s.

The cells “basically became obese” and “could no longer digest plaque formations,” dentist Dr. Alpdogan Kantarci said in a news release about the study. Kantarci is a senior staff member at the oral health-focused Forsyth Institute and senior author on the study, published this week in the Journal of Neuroinflammation.

Scientists aren’t fully sure what causes the cell death and tissue loss that occurs in the brains of Alzheimer’s disease patients. But they believe it involves the buildup of amyloid plaques and “tau tangles”—another type of protein clump—as the brain loses its ability to properly rid itself of such debris.

The study demonstrates the importance of controlling gum disease—especially given its ability to cause inflammation in the brain and trigger neurodegeneration, Kantarci emphasized.

“The mouth is part of the body, and if you don’t take care of oral inflammation and infection, you cannot really prevent systemic diseases like Alzheimer’s in a reproducible way,” he said.

How to prevent gum disease

Gum disease occurs when someone fails to brush and floss properly, allowing plaque—a film of bacteria, in this case—to accumulate and harden on teeth. This can lead to gums that are swollen, red, and bleed easily—and, eventually, to painful chewing and the need to remove teeth, according to the U.S. National Institutes of Health (NIH).

Research suggests that gum disease can impact health in other parts of the body as well. A 2020 study published in the journal Cancer Prevention Research found that people with gum disease and tooth loss had a greater chance of developing colon cancer. And those with gum disease have double or triple the risk of having a heart attack, stroke, or other cardiovascular event, according to Harvard Medical School.

When it comes to gum disease, signs to look for include the following, according to NIH:

• Red, swollen, tender, or bleeding gums
• Gums that pull away from the teeth, making them appear longer
• Loose or sensitive teeth
• Pain while chewing
• Persistent bad breath

To keep gums and teeth healthy, the NIH recommends the following:

• Brush teeth twice daily with fluoride toothpaste
• Regularly floss between teeth
• Visit the dentist regularly
• Don’t smoke, or quit smoking if you do

Signs of Alzheimer’s disease

Those who are concerned they or a loved one might have Alzheimer’s or another form of dementia should talk to their doctor, who may recommend they see another specialist, like a neuropsychologist or a neurologist.

Warning signs of the condition, according to the AARP, include:

• Difficulty performing daily tasks like keeping track of bills and following a recipe while cooking
• Repetition, such as asking the same question over and over and telling the same story multiple times
• Struggling to find the right word
• Getting lost
• Personality changes, such as becoming more anxious, confused, afraid, or paranoid
• Confusion about time and place, especially if someone can’t remember where they are or how they got there
• Misplacing items in unusual areas
• Trouble with hygiene
• Trouble with handling money
• Sudden loss of things one is usually interested in, including family, friends, work, and social events
• Forgetting old memories