Losing teeth in old age may do more than make eating difficult—it could also affect how the brain works. A new study from Hiroshima University in Japan shows that mice who lost their molars experienced memory problems, even though they were still getting enough nutrition.
The research was published in the Archives of Oral Biology and led by Rie Hatakeyama, a postdoctoral researcher at the university’s Graduate School of Biomedical and Health Sciences. She explained that while many older adults lose teeth, it hasn’t been clear whether the tooth loss itself harms brain function.
To investigate this, the team studied older male mice that are known to age quickly. They split the mice into four groups: one group had a normal diet and kept their teeth, another had a low-protein diet but kept their teeth, a third group had their molars removed but ate a normal diet, and the last group had both tooth loss and a low-protein diet.
Six months later, the researchers tested the mice’s memory using behavioral tests and examined their brain tissue. The most important finding was that mice who lost their molars performed worse on memory tests—even if they were eating a healthy, protein-rich diet. This means the act of chewing may help keep the brain healthy.
The scientists found more signs of inflammation and cell death in the brains of mice that lost their teeth. They focused on the hippocampus, a part of the brain that is key for memory and learning. The areas most affected were the CA1 and dentate gyrus.
These are regions that help form and store memories. Losing teeth caused damage in these areas, while the low-protein diet mainly affected a different part of the hippocampus, called the CA3, which helps with recognizing patterns.
The researchers also looked at specific markers of cell death. They found that tooth loss alone increased these markers, suggesting that the brain was moving toward more cell death and less survival. The low-protein diet had a much smaller effect.
This study shows that it’s not just about what we eat, but how we eat. Chewing seems to stimulate the brain in ways that protect memory and mental sharpness. It supports earlier research linking poor oral health with problems like memory loss and dementia.
The lead researcher, Rie Hatakeyama, said she was surprised that something happening in the mouth could have such a strong effect on the brain. She believes that keeping the ability to chew—even with the help of dentures or other dental treatments—could help prevent mental decline in older adults.
Her team plans to do more studies to understand exactly how chewing helps the brain. They want to look at changes in brain activity, chemicals that send signals in the brain, and the growth of new brain cells. Their ultimate goal is to show that restoring the ability to chew can help older people keep their minds sharp.
This research sends a clear message: take care of your teeth, because they may be more important to your brain than you think.
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
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