A team of New York-based researchers analyzed national data on more than 2,500 people age 50 and up. Here’s what they discovered: Diabetics—including those with type 1 and type 2 diabetes—were missing an average of nearly 10 teeth at the time of oral examination compared to non-diabetics, who were short fewer than seven teeth. And that’s not all: Diabetics were also twice as likely to suffer from edentulism, a complete absence of teeth; twenty-eight percent of diabetes sufferers were toothless, compared to just 14% of those without diabetes.  More from Prevention: 7 Weird Things Your Teeth Are Trying to Tell You The study authors say there may be several ways to explain the connection between diabetes and tooth loss. One theory is that hyperglycemia—or high blood sugar—disrupts the delivery of nutrients and removal of waste products from the tissue in the gums. Over time, that leads to periodontal disease and, eventually, to tooth loss. While those who have poorly controlled diabetes are most likely to experience tooth decay, even well-managed diabetics are more likely to suffer from periodontal disease.  What should diabetics do to protect themselves? Apart from brushing twice a day and flossing regularly, some diabetics may need to visit their dentist four times a year for a professional tooth and gum cleaning, says study co-author Jayanth Kumar, DDS, MPH, of the New York State Department of Health’s bureau of dental health. Gum disease starts when bacteria on your teeth harden into tartar, and only your dentist can clear that tartar away. Avoid sugary snacks, which are well-known tooth decayers, and reach for crunchy foods like apples, celery, and carrots that will actually clean your chompers as your chew. For more good food choices—and not-so-good ones—see 25 Foods Dentists Won’t Eat.