Dentists are considering a return to an old theory that dietary carbohydrates first cause dental diseases, then certain systemic chronic diseases, according to a review in the June 1, 2009, Journal of Dental Research.
We’ve known for years that some dental and systemic diseases are associated with each other, both for individuals and populations. For example, gingivitis and periodontal disease are associated with type 2 diabetes and coronary heart disease. The exact nature of that association is not clear. In the 1990s it seemed that infections—chlamydia, for example—might be the unifying link, but this hasn’t been supported by subsequent research.
The aforementioned article is written by Dr. Philippe P. Hujoel, who has been active in dental research for decades and is affiliated with the University of Washington (Seattle). He’s no bomb-throwing, crazed, radical.
That's more like it
The “old theory” to which I referred is the Cleave-Yudkin idea from the 1960s and ’70s that excessive intake of fermentable carbohydrates, in the absence of good dental care, leads both to certain dental diseases—caries (cavities), periodontal disease, certain oral cancers, and leukoplakia—and to some common systemic chronic non-communicable diseases such as coronary heart disease, type 2 diabetes, some cancers, and dementia. In other words, dietary carbohydrates cause both dental and systemic diseases—not all cases of those diseases, of course, but some.
Dr. Hujoel doesn’t define “fermentable” carbohydrates in the article. My American Heritage Dictionary defines fermentation as:
- the anaerobic conversion of sugar to carbon dioxide and alcohol by yeast
- any of a group of chemical reactions induced by living or nonliving ferments that split complex organic compunds into relatively simple substances
As reported in David Mendosa’s blog at MyDiabetesCentral.com, Dr. Hujoel said, “Non-fermentable carbohydrates are fibers.” Dr. Hujoel also shared some personal tidbits there.
In the context of excessive carbohydrate intake, the article frequently mentions sugar, refined carbs, and high-glycemic-index carbs. Dental effects of excessive carb intake can appear within weeks or months, whereas the systemic effects may take decades.
Hujoel compares and contrasts Ancel Keys’ Diet-Heart/Lipid Hypothesis with the Cleave-Yudkin Carbohydrate Theory. In Dr. Hujoel’s view, the latest research data favor the Carbohydrate Theory as an explanation of many cases of the aforementioned dental and systemic chronic diseases. If correct, the theory has important implications for prevention of dental and systemic diseases: namely, dietary carbohydrate restriction.
Juvenile male Homo sapiens on Neolithic diet
Adherents of low-carb diets will love this article; it supports their choices. The standard American diet provides 55% of energy in the form of carbohydrates. Stone Age diets on average provided 35 to 40% of energy as carbs, but rarely as the simple sugars and refined starches that characterize modern Western diets.
I agree with Dr. Hujoel that we need a long-term prospective trial of serious low-carb eating versus the standard American high-carb diet. Take 20,000 people, randomize them to one of the two diets, follow their dental and systemic health over 15-30 years, then compare the two groups. Problem is, I’m not sure it can be done. It’s hard enough for most people to follow a low-carb or paleo diet for four months. And I’m asking for 30 years?!
Dr. Hujoel writes:
Possibly, when it comes to fermentable carbohydrates, teeth would then become to the medical and dental professionals what they have always been for paleoanthropologists: “extremely informative about age, sex, diet, health.”
Dr. Hujoel mentioned a review of six studies that showed a 30% reduction in gingivitis score by following a diet moderately reduced in carbs. He mentions the aphorism: “no carbohydrates, no caries.” Anyone prone to dental caries or ongoing periodontal disease should do further research to see if switching to low-carb eating might improve the situation.
Don’t be surprised if your dentist isn’t very familiar with the concept. Has he ever mentioned it to you?
Steve Parker, M.D.
Reference: Hujoel, P. Dietary carbohydrates and dental-systemic diseases. Journal of Dental Research, 88 (2009): 490-502.
Mendosa, David. Our dental alarm bell. MyDiabetesCentral.com, July 12, 2009.