Could the Way You Chew Food Affect Your Dementia Risk?

Losing teeth may affect more than a person’s ability to eat comfortably. Growing research suggests that tooth loss is associated with a higher risk of cognitive decline and dementia. But scientists are still trying to understand why.

A 2026 meta-analysis of 21 longitudinal studies involving about 35.7 million people found that tooth loss was associated with a higher risk of dementia and mild cognitive impairment, with the risk increasing as more teeth were lost. It may not be oral disease alone that matters; the loss of chewing ability itself could also play a role.

Still, these findings do not establish a clear cause-and-effect relationship. “The relationship may work in several ways. The location of the missing teeth may also matter,” says Mill Etienne, vice chancellor and professor of neurology and medicine at New York Medical College.

“Loss of the back teeth, which do most of the chewing, may matter more than the total number of teeth. Chewing ability itself, as opposed to tooth count, is measured less often, so its separate contribution is less certain,” he says.

Several other factors may also influence the relationship between tooth loss and dementia, says Jordan Weiss, an assistant professor in the Division of Precision Medicine and Optimal Aging Institute at NYU Grossman School of Medicine. Years of smoking, diabetes, vascular disease, and limited access to dental care can affect oral health. Some of these factors also influence brain health. Education, income, and access to health care may further shape both.

Early cognitive changes can complicate the picture, too. Someone who begins experiencing memory or thinking difficulties may find it harder to maintain oral hygiene or seek dental treatment, Weiss says.

Chewing does more than break down food. It activates sensory pathways and engages several areas of the brain.

“Chewing has a significant effect on blood flow,” says Steven Chance, a former associate professor of neuroscience at the University of Oxford and founder and chief scientific officer of Oxford Brain Diagnostics, a University of Oxford spinout. “Reduced chewing may reduce blood flow, and because blood flow supports brain activity, that activity may be reduced, too.”

(Chewing gum has a mysterious effect on the brain.)

Some brain-imaging studies have found differences in brain structure among older adults with fewer teeth or poorer chewing ability. A recent review in the Journal of Oral Rehabilitation examined eight MRI studies of adults aged 60 and older. Five of six analyses found that poorer chewing ability or greater tooth loss was associated with smaller volumes in the hippocampus, a brain region involved in learning and memory, and nearby areas. In one study, every 10 fewer teeth was associated with about 2.2 percent lower volume in both hippocampi.

A separate expert review in Archives of Oral Biology explores possible biological explanations for this relationship. It discusses evidence that reduced chewing, especially after the loss of back teeth, may affect hippocampal activity and neurogenesis, the formation of new neurons. Chewing may also influence levels of brain-derived neurotrophic factor (BDNF), a protein that supports neuron growth and survival. Much of the evidence, however, comes from animal studies, and further research in humans is needed.

Other researchers have begun testing whether changes in chewing habits can affect cognitive performance. In a 2026 randomized trial involving 50 older adults, participants encouraged to chew more frequently during meals showed improvements in memory after one month compared with those who maintained their habits. Researchers also observed changes in blood oxygenation in the prefrontal cortex, a brain region involved in working memory and executive function.

Problems with chewing and dental health can also limit the foods and flavors people enjoy and make social activities, such as eating with others, more difficult. These changes may reinforce one another, Chance says, with reduced stimulation potentially affecting how the brain processes information.

Research has begun to examine whether restoring chewing function might also benefit the brain. A three-year cohort study, published in Frontiers in Oral Health, followed older adults with tooth loss. Those who used dental prostheses to replace missing teeth had a 9 percent lower risk of overall functional decline and a 13 percent lower risk of decline in intellectual activities, such as reading newspapers or books and keeping up with health-related news.

(These surprising early symptoms may be linked to Alzheimer's.)

Replacing missing teeth can restore some of the chewing function that is lost, though dentures and implants work differently from natural teeth. Natural teeth have a periodontal ligament, says Niels Oestervemb, a Diplomate of the American Board of Oral Implant Dentistry and founder of Winchester Dental Implant & Sedation Center in Virginia. He describes it as “a bunch of elastic fibers that hold the tooth.” Every time a person bites, these fibers are stressed, allowing them to sense how hard they are biting. This sensory feedback helps the brain coordinate chewing and adjust the force needed to break down different foods.

“Implants don't have the periodontal ligament, but when you bite on them, they actually transfer the force to the bone. That's why you can still get some feedback with implants,” he says. “If you look at natural teeth and implants, they'll be very close to each other in terms of bite force. But if you look at a complete denture, you're probably looking at about a fifth of the bite force.”

“It is reasonable to hypothesize that restoring chewing function earlier might help preserve sensory stimulation and nutrition,” says Etienne. “However, we do not have convincing evidence that replacing teeth immediately produces better long-term cognitive outcomes than replacing them years later. This remains an important research question.”