Gum disease may have ties to Alzheimer’s

Oral bacteria can go through the bloodstream to the brain during chewing, brushing, flossing, and during dental procedures and can potentially lead to degeneration in tissue that appears similar to Alzheimer’s disease. (Credit: iStockphoto)

Oral bacteria from poor dental hygiene have been linked to brain tissue degeneration, a finding that shows a potential association between gum disease and Alzheimer’s disease.

Researchers examined samples from the brains of patients with and without dementia and found lipopolysaccharide, a component of Porphyromonas gingivalis, an oral bacterium, in four out of 10 Alzheimer’s disease brain samples.


It was not found in any samples from the brains of people who did not have Alzheimer’s disease.

“This clearly shows that there is an association between oral bacteria and Alzheimer’s disease, but not causal association,” says LakshmyyaKesavalu, associate professor of periodontology at the University of Florida says.

Oral bacteria can enter the bloodstream during chewing, brushing and flossing, and during dental procedures. The bacteria can enter through the bloodstream to the brain and can potentially lead to degeneration in brain tissue that appears similar to Alzheimer’s disease.

The researchers say the study, published in the Journal of Alzheimer’s Disease, is the first to show a link between the existence of the oral bacterium component lipopolysaccharide and Alzheimer’s disease.


The study follows previous work on mice infected with four major periodontal pathogens. In that unpublished study, researchers found the oral bacterium moved to the brain in the mice as well, further confirming the group’s research on humans.

More common that the cold

Gingivitis is seen in 97 percent of the population and is one of the most common diseases to affect humans, more common than the common cold.

According to the Centers for Disease Control and Prevention, about 64 percent of seniors age 65 and over have moderate or severe periodontal disease. Alzheimer’s disease, according to the Alzheimer’s Association, is the sixth leading cause of death in the United States—affecting more than 5 million Americans.

The brain disease costs the US both money and lives. One in three senior citizens dies from Alzheimer’s or another form of dementia. In 2013 Alzheimer’s is projected to cost the country $203 billion, according to the Alzheimer’s Association.

“Right now, globally about 36 million people are affected by Alzheimer’s disease (according to the World Health Organization) and it may go up to 115 million by 2050,” Kesavalu says.

Although the findings don’t prove that oral bacteria causes Alzheimer’s disease, preventing gum disease is still a good idea.

“People should brush their teeth regularly twice a day. Second, they can floss their teeth regularly so there are no bacteria plaques between teeth, and third, they can visit their dentist for regular cleanings. Fourth, not smoking,” Kesavalu says.

Kesavalu says he next plans to study the causal association between major periodontal bacteria and Alzheimer’s disease in mouse models.

Researchers from the University of Central Lancashire and The Blizzard Institute in the UK contributed to the study.

Source: University of Florida