Dental disease is a wake-up call that your diet is harming your body, concludes Dr. Philippe P. Hujoel. He reviewed the two hypotheses about whether or not dental disease is a warning that we are headed toward chronic system illness. After examining all the evidence, he concludes that it is.

"The five-alarm fire bell of a tooth ache is difficult to ignore," Dr. Hujoel told me. He is professor of dental public health sciences at the University of Washington School of Dentistry in Seattle.

But we do tend to ignore it.

He lays the blame squarely at the feet of Ancel Keys and his believers. Dr. Keys promulgated the lipid hypothesis and focused on excess fat intake as the primary cause of systemic chronic non-communicable diseases -- like diabetes. For Dr. Keys a healthy diet consisted of increasing our intake of "fermentable carbohydrates."

I asked Dr. Hujoel what he meant by fermentable in this context. "Non-fermentable carbohydrates are fibers," he replied. So fermentable carbohydrates are what we usually call available or net carbs.

As a result of the tireless efforts that Dr. Keys made, the medical establishment has come to regard dental diseases as local dietary side effects. The authorities came to view dental diseases as local infections that dentists could treat with fluorides, sealants, oral hygiene, antimicrobials, and dental fillings.

But now clinical trials are putting the opposing dietary hypothesis to the test and are beginning to prove the link between dental and systemic diseases. Dental problems in the short term may in fact portend potentially serious chronic diseases in the long term.

Two physicians, Thomas Cleave and John Yudkin, were the two leading protagonists of the counterargument. Dr. Cleave hypothesized that fermentable carbohydrates such as white flour and white or brown sugar caused many Western diseases, including both dental diseases and diabetes. Dr. Yudkin wrote that sugar causes both dental and chronic non-communicable diseases.

The Journal of Dental Research just published Dr. Hujoel's review of the evidence for and against the dietary link between dental disease and chronic diseases. He calls his review "Dietary Carbohydrates and Dental-Systemic Diseases."

Dr. Hujoel says that for years some medical establishments have told us to make fermentable carbohydrates the foundation of our diet. They say that fats are evil. They assume that we could prevent many systemic chronic diseases by eating a diet high in carbohydrates. Unfortunately, that diet is bad for our dental health and we end up with cavities and gum disease.

But Dr. Hujoel asks whether fermentable carbohydrates are also bad for our systemic health. He explores the close connection between our biology that causes dental problems and those that spike our blood glucose levels. Eating fermentable carbohydrates is now accepted as initiating dental disease.

"Eating these same foods," he says, "is also associated with spikes in blood sugar levels. There is fascinating evidence that suggests that the higher the glycemic level of a food, the more it will drop the acidity of dental plaque and the higher it will raise blood sugar. So, possibly, dental decay may really be a marker for the chronic high-glycemic diets that lead to both dental decay and chronic systemic diseases."