Having teeth so jacked up that you eventually lose them presents issues of aesthetics and nutrition. A new study from Hiroshima University suggests that it might also be a brain problem, as molars pulled in aging mice led to memory loss and measurable brain changes, even when their diets stayed nutritionally adequate.
Researchers followed a strain of mice prone to age-related cognitive decline for six months after removing their upper molars. To test whether memory issues were caused by poor nutrition, the scientists fed some mice a normal-protein diet and others a protein-restricted one. This was to mimick what can happen when elderly people avoid hard-to-chew foods like meat and fish.
The researchers found that tooth loss predicted memory problems regardless of protein intake.
Scientists Found a Link Between Tooth Loss and Memory Loss in Mice
A Barnes Maze is a standard method of testing spatial memory in mice. Picture a circle with up to 20 holes along the edge. Beneath one of the holes is an “escape box” that the mouse can nestle within.
The researchers ran mice through the maze and found that the mice without teeth struggled to remember where the escape box was, wandering longer and more erratically than mice with all their teeth intact. Body weight was stable across all groups, ruling out starvation or just general poor health, suggesting that whatever was going on, again, it had nothing to do with diet.
Toothless mice showed higher levels of molecular markers linked to programmed cell death in the hippocampus, the brain’s memory center, along with increased inflammation and fewer cells identified as neurons in key memory regions.
The study, published in Archives of Oral Biology, doesn’t claim that missing some teeth directly leads to dementia. These were mice, not people, and the sample sizes were small. But the findings are yet another example and a growing field of evidence showing that oral health and brain health are tightly linked.
As the researchers of this particular study suggest, which matches what other research teams around the world are finding independently, gum disease and tooth loss involve chronic inflammation, which could ripple out toward the brain.
That’s just one theory. Another suggests that the sensory input of chewing sends signals through nerves and into regions of our brain involved in learning and memory. Remove teeth, and those signals disappear.
If future human studies start finding a similar link, then your trips to the dentist might not just be brightening your smile and keeping your breath from perpetually smelling like death, but it might be keeping your memory intact.
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