Medically reviewed by Anna Goldman, MD.

A new study suggests that brushing your teeth twice per day could improve your blood sugar control.

The surprising report, authored by researchers from the MedStar Diabetes Institute and the American Dental Association, was published in Diabetes Spectrum and highlighted at the recent annual conference of the Association of Diabetes Care & Education Specialists (ADCES). The authors conducted a new review of previous work on the connections between oral hygiene and glycemic control.

The researchers identified 11 studies in the existing medical literature that explored the connection between oral hygiene and blood sugar levels of adults with type 2 diabetes. These studies consistently showed that adults who brushed their teeth more often had better glucose control. Frequent brushers had significantly better A1C results, or better fasting and/or post-prandial glucose levels, than those who brushed their teeth less often. (Unsurprisingly, the studies also showed that more frequent tooth brushing resulted in better oral health.)

“The available data,” the authors conclude, “suggest that improved engagement in toothbrushing behavior may be associated with improved oral health and better glycemic control in people with type 2 diabetes.”

While the results need to be taken with a grain of salt — the review didn’t include any large, robust interventional studies — they actually weren’t entirely unexpected. In fact, there’s quite a lot of evidence tying oral health and diabetes control.

It’s possible that an unhealthy oral environment can cause a subtle but real decline in blood sugar control. This can lead to a vicious cycle as uncontrolled diabetes tends to cause chronic inflammation, negatively impacting immune cell function and exacerbating periodontal issues. In the mouth, you can help your body’s fight against inflammation by cleaning regularly, which may indirectly benefit glycemic control. This is most evident in the case of gum disease (periodontitis), a serious infection of the gums:

A 2018 study in The Lancet conducted an experiment on adults with both type 2 diabetes and periodontal disease. Patients who were randomly assigned to receive an intensive intervention to correct gum disease — including thorough cleaning and regular dental visits — had an A1C 0.5 percent lower than those receiving conventional care. The authors suggested that gum disease treatment and “routine oral health assessment … could be important for effective management of type 2 diabetes.”
The International Diabetes Federation and the European Federation of Periodontology have co-authored a consensus statement on the “bidirectional relationship” between diabetes and gum disease, citing evidence that enhanced gum care leads to blood sugar improvements.
A 2021 article explains that “systemic inflammation” due to gum disease can directly cause blood sugar increases.

There may be other complex factors at play — oral health is often considered a window to your overall health and has surprising connections to brain and heart health, according to Everyday Health. And, as the National Institutes of Health points out, oral health problems can be frustrating and painful, making it more difficult to stick to a healthy diabetes management plan.

It’s also possible that the effect is indirect. Maybe brushing teeth twice a day simply puts people in the right mindset to engage in other healthy habits — like eating healthy meals, exercising, or monitoring blood sugar levels.

The American Diabetes Association recommends that people with diabetes see a dentist at least twice per year. Ideally, your dentist should be “aware of the needs of people with diabetes,” and you should keep them well informed about your health (including your A1C level) and the medications you use.

We know that glucose control and oral hygiene influence each other in the opposite direction, too. Oral health problems are extremely common in diabetes, for a variety of reasons:

Hyperglycemia actually raises the sugar content of saliva, making the mouth of a person with diabetes more hospitable to bacteria.
Sugary saliva speeds tooth decay, just like sugary foods.
Diabetes can inhibit the immune system, slowing down the response to infections.
High blood sugars also reduce salivary flow, leading to dry mouth and an increase in harmful oral bacteria.

Blood sugar control really matters for oral health. In a 2022 study, researchers found that children with type 1 diabetes with good metabolic control had lower rates of cavities, plaque, gingivitis, and other measures of oral health — even though they didn’t brush their teeth or visit the dentist any more frequently than children with “poor” metabolic control.

Takeaways

We know that proper diabetes management is good for oral health, but it’s possible that the opposite is also true: Taking care of your teeth might be good for your blood sugar levels.

Scientists are only beginning to understand why tooth brushing and good oral hygiene might be helpful for blood sugar control. Maybe good oral hygiene can actually reduce chronic inflammation, lowering glucose levels. Or maybe it just puts people in the right frame of mind to tackle their diabetes management. Either way, health experts agree that taking care of your gums and teeth is a sneakily important part of overall health, especially if you have diabetes.

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