Alzheimer’s might be linked to gum disease bacteria, scientists say

In case you needed more reason to floss, scientists say a growing body of research indicates that Alzheimer’s disease might be linked to Porphyromonas gingivalis, a strain of bacteria that’s also known for causing chronic gum disease, New Scientist reports.

Scientists know structures called amyloid plaques are often found in the brains of people who died with Alzheimer’s disease, but so far efforts to curb formation of those plaques haven’t done much to stop the disease. Now some scientists think the proteins that form those plaques might actually be part of the brain’s defense against bacteria, including P. gingivalis.

Recent studies in rodents have found the bacteria do infect regions of the brain affected by Alzheimer’s, that gum infections can worsen symptoms in mice genetically engineered to get Alzheimer’s, and that gum infections can seemingly lead to brain inflammation and amyloid plaques in previously healthy mice.

Researchers at Cortexyme, a San Francisco pharmaceutical company, are looking into a potential drug to block the gum bacteria’s apparent effects in the brain. An early study found the compound appeared to be safe and seemed to have a positive effect on Alzheimer’s patients, the company says.

Assuming the hypothesis is right, it’s still not quite clear when and how the bacteria migrate from the gums to the brain and start doing damage, since far more people have gum disease than Alzheimer’s.

It’s possible that news of the possible link will lead to people spending more time on their dental health than they currently do, though: One study found less than one third of Americans floss daily. And while reports a few years ago pointed out that there hasn’t been a particularly rigorous study showing the benefits of flossing, most dentists still recommend the practice as a way to keep teeth clean, and it’s hard to argue that removing decaying food from around teeth could be a bad idea.