You’ve heard that poor oral health can be linked to heart disease. But researchers have recently found the same oral bacteria that invades arteries also can be linked to dementia and Alzheimer’s disease.

The link between our mouths and our bloodstream is a lot closer than we might imagine. Cuts in our mouths from eating or brushing can ferry microbes into the blood system and throughout our bodies. Invasive dental procedures and surgeries that require intubation are even bigger culprits of introducing germs into the bloodstream.

Researchers from the United Kingdom found bacteria in the brains of patients who had Alzheimer’s disease and dementia. When this particular strain of bacteria enters the brain, it can trigger a release of immune system chemicals that can kill neurons.

The death of these neurons could lead to symptoms of dementia, such as confusion and poor memory.

Dementia is not the only danger from mouth bacteria. Ann Progulske [Pro-gull-ski]–Fox, Ph.D., a researcher at the University of Florida College of Dentistry, established the link between gum disease and heart disease when she found two kinds of oral bacteria in the artery plaque of people with heart disease.

The theory is that dental bacteria get into the bloodstream, then take up residence in arterial walls. But scientists suggested that the bacterial fragments found in arterial walls were from bacteria killed by the immune system. Progulske-Fox grew live bacteria from bacteria found in a person’s artery, proving that the bacteria had been living inside the artery walls.

Not all strains of mouth bacteria can do this, but at least two have been identified. So keep your mouth clean for a healthy heart as well as a healthy mind.