A group of people eating food and laughing while the one on the right covers their mouth as they chew their foodShare on Pinterest
Paying attention to oral health may help improve blood sugar control. Jayme Burrows/Stocksy
  • For people with type 2 diabetes, difficulty chewing due to lost or non-functional teeth is associated with higher levels of blood glucose, according to a new study.
  • One possible reason is that an inability to chew properly is linked to obesity.
  • People who have trouble chewing may also gravitate to lower-quality foods that are easy to chew.
  • The study’s co-author suggests that dental work that restores proper chewing may be a good way to return blood glucose to healthier levels in such people.

A new study explores for the first time an association between difficulty chewing and blood glucose levels in people with type 2 diabetes.

People with type 2 diabetes who can chew their food normally have lower blood glucose levels than those whose chewing is impaired due to lost or broken, damaged teeth.

The study analyzed data from 94 people with type 2 diabetes who were patients at a clinic in Istanbul, Turkey. Individuals were assigned to one of two groups.

The first group consisted of people who could chew properly. They had acceptable “occlusal function,” meaning that they had enough teeth to chew properly and that their upper and lower teeth successfully met during chewing.

In the second group were people who could not chew well because they were missing too many teeth to do so.

To assess the participants’ average blood sugar levels, the researchers measured their levels of hemoglobin A1c (HbA1c). HbA1c reflects a person’s average blood glucose over the past 2–3 months.

The study found that the second group’s HbA1c levels were 2% higher than those who could chew effectively.

The HbA1c level for those who had no chewing issues was 7.48. The same figure was 9.42 for those with difficulties chewing.

The study is published in PLOS One.

In type 2 diabetes, the pancreas does not produce enough insulin, and too much glucose remains in the bloodstream, potentially leading to various complications.

Unmanaged type 2 diabetes is linked to an increased risk of stroke and heart attack, nerve damage, kidney disease, vision and hearing problems, skin conditions, dementia, sleep apnea, and slow healing. It is a major cause of “blindness, kidney failure, heart attacks, stroke, and lower limb amputation,” according to the World Health Organization.

In the U.S., the Centers for Disease Control estimates that about one in 10— or 37 million—Americans have diabetes. About 90-95% of them have type 2 diabetes.

Recognized approaches to managing type 2 diabetes include maintaining a healthy weight, regular physical activity, eating a healthy diet, not smoking, and effectively regulating blood pressure.

While oral health is becoming more widely recognized as a player in controlling type 2 diabetes, there has never been an investigation specifically targeting chewing—or mastication—as a factor in type 2 diabetes.

Study co-author Dr. Mehmet A. Eskan is an assistant professor at the University at Buffalo School of Dental Medicine in New York State. In his practice, he works with systemically compromised patients, some of whom have type 2 diabetes. He routinely checks patients’ systemic blood work after treatment.

“I noticed that my patients who presented type 2 diabetes and diminished or lack of chewing function improved their blood glucose levels after regaining full occlusal support, which was usually utilized by implant-supported restoration,” he recalled.

The study was co-written by Dr. Yeter E. Bayram of the Department of Internal Medicine at the Hamidiye Şişli Etfal Education and Research Hospital in Istanbul, Turkey.

Although the difference in HbA1c levels may not seem like much, Dr. Eskan explained why it is significant. He said previous research found that just a 1% increase in A1c concentration was associated with a roughly 40% increase in cardiovascular or ischemic heart disease mortality among diabetic patients.

“Accordingly, our results could indicate having a full chewing function in patients with type 2 diabetes could reduce more than 50% of cardiovascular complications seen in type 2 diabetes,” Dr. Eskan said.

Digestion begins in the mouth as we eat, explained Dr. Sumera Ahmed:

“The first step in ingestion of food is chewing, which breaks down the food particles and reduces the size, increases the surface area-to-volume ratio to facilitate swallowing. This also aids in absorption of nutrients.”

How chewing and hunger are linked

“The act of chewing or mastication sends feedback signals to the hypothalamus satiety center in the brain, resulting in decreased food intake.”
— Dr. Sumera Ahmed

Ahmed also noted that eating further releases incretin hormones, which stimulate a decrease in blood glucose levels, specifically “GLP-1 [and] GIP from the L-cells in the intestines, which slow gastric emptying, stimulate insulin secretion and suppress appetite.”

There are a few reasons experts are now more interested in the quality of oral health related to type 2 diabetes.

Dr. Eskan cited earlier research finding edentulism — a total loss of teeth — is strongly associated with cardiovascular deaths.

He also reported “a tendency to obesity in individuals presenting a lack of chewing function. And chronic gastric inflammation can be promoted by chewing function.”

“Indeed, our preliminary data [for an upcoming study] showed gastric inflammation is higher in the patient, presenting diminished mastication function than the patients having full mastication support,” he said.

Difficulty with chewing may also lead to lower-quality food.

“I think the main reason is that food that is soft and easy to swallow is generally higher in sugar (juices, fruit compotes, sugary yogurts, starchy vegetables), compared to protein and more fibrous foods,” explained endocrinologist Ana Maria Kausel.