If morning breath is not enough of an incentive to brush your teeth, this might be: Gum disease and tooth loss may shrink your brain.
Researchers in Japan found that gum disease and tooth loss were associated with shrinkage in the hippocampus, an area of the brain involved in memory and often damaged in patients with Alzheimer's.
Nearly half of all adults over 30 in the U.S. show some signs of gum disease, with 9 percent having signs of severe gum disease, according to the Centers for Disease Control and Prevention. Meanwhile, Alzheimer's is the sixth-leading cause of death among U.S. adults.
But how can our oral health affect our brains?
"Previous studies have shown that chronic peripheral inflammation may increase the risk of dementia and progress hippocampal atrophy, aka brain shrinkage," study author Satoshi Yamaguchi, who is at Tohoku University, told Newsweek.
"Periodontal disease [gum disease] is chronic inflammation in the oral cavity and may have adverse effects on the hippocampus through inflammation," he continued. "It has also been suggested that the [microbes causing gum disease] may invade the brain and damage nerve tissue."
As for tooth loss, Yamaguchi said missing teeth could reduce chewing stimulation, which has been shown to cause brain shrinkage.
However, Yamaguchi was keen to stress that the study itself does not prove there is a causal relationship between gum disease and brain shrinkage. "This study only showed that the number of teeth and periodontal disease were associated with the rate of hippocampal atrophy," he said.
The link between tooth loss and brain health may also be affected by other factors. "Because the number of teeth tends to decrease with age, the association between fewer teeth and increased hippocampal atrophy rate may be confounded by age," Yamaguchi said.
The study, published Wednesday in the journal Neurology, looked exclusively at participants over 55 in a fairly small sample size of 172 individuals.
"We need to confirm the generalizability of our findings by studying a larger and more diverse group of individuals," Yamaguchi said. "Then intervention studies are needed to confirm the causal relationship and to elucidate the mechanism" underlying these associations.
Despite these limitations, the study provides convincing evidence that maintaining good oral hygiene could protect us from brain disease later in life. "It may be better to extract teeth with severe, difficult-to-treat periodontal disease and replace them with appropriate dentures than to keep the teeth at all costs," Yamaguchi said.
He added that gum disease is a "silent disease" and can become severe without pain. "In addition, there are no clear criteria for deciding whether to extract a tooth with periodontal disease. It is important to see a trusted dentist regularly," he said.
Uncommon Knowledge
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
