No Dentist Ever Told Me, “No Carbs, No Cavities”

But it’s true to a great extent. And the worst carbohydrates for your teeth seem to be sugars.

173 Years of U.S. Sugar Consumption

(Thanks to Dr. Stephan Guyenet and Jeremy Landen for this sugar consumption graph.)

MNT on September 16, 2014, published an article about the very prominent role of sugars as a cause of cavities, aka dental caries. This idea deserves much wider circulation.

I’ve written before about the carbohydrate connection to dental health and chronic systemic disease. Furthermore, sugar-sweetened beverages are linked to 200,000 yearly worldwide deaths

Investigators at University College London and the London School of Hygiene & Tropical Medicine think the World Health Organization’s recommendation of a maximum of 10% total daily calories from “free sugar” should be reduced to 3%, with 5% (25 grams) as a fall-back position.

Six teaspoons of granulated table sugar (sucrose) is 25 grams. That should be enough daily sugar for anyone, right? But it’s incredibly easy to exceed that limit due to subtly hidden sugars in multiple foods, especially commercially prepared foods that you wouldn’t expect contain sugar. Chances are, for instance, that you have in your house store-bought sausage, salad dressings, and various condiments with added sugars such as high fructose corn syrup. Sugar’s a flavor enhancer.

tooth structure, paleo diet, caries, enamel

Cross-section of a tooth

The aforementioned “free sugar” as defined as any monosaccharides and disaccharides that a consumer, cook, or food manufacturer adds to foods. In the U.S., we just call these “added sugars” instead of free sugars. From the MNT article, “Sugars that are naturally present in honey, syrup, and fruit juices are also classed as free sugars.” Sugar in the whole fruit you eat is not counted as free or added sugar.

The London researchers found that—in children at least—moving from consuming almost no sugar to 5% of total daily calories doubled the rate of tooth decay. This rose with every incremental increase in sugar intake.

From the MNT article:

“Tooth decay is a serious problem worldwide and reducing sugar intake makes a huge difference,” says study author Aubrey Sheiham, of the Department of Epidemiology & Public Health at University College London. “Data from Japan were particularly revealing, as the population had no access to sugar during or shortly after the Second World War. We found that decay was hugely reduced during this time, but then increased as they began to import sugar again.”

I’m convinced. How about you?

Steve Parker, M.D.


Filed under Sugar

11 responses to “No Dentist Ever Told Me, “No Carbs, No Cavities”

  1. Do you expect anyone to sabotage there own profession’s growth?

    • I’d like to think it’s more akin to physicians thinking that dietary saturated fat and cholesterol cause heart attacks. Many professionals just never take a close look at what they’re taught in school. Most lack the time, some lack curiosity.

  2. Nick

    I know from experience (ever since I started experimenting with a carb free diet a number of years ago) that no carbs (no starch, no sugar, no vegetables, no sugars from milk and so forth) inevitably equals clean, smooth teeth. If you want teeth with a nasty layer of whatever it is on it, the worst is not plain sugar or sugar in fruits (not by far), but starch (potatoes, spaghetti, bread, cake a.s.f.). So maybe when judging the effect on teeth, researchers should distinguish between products in more detail.

  3. Excellent post! It is not true about dentists not telling people though. I was married to one and I assure you it has been part of the nagging from dentists to their clients for well over fifty years.

  4. Jim Jozwiak

    My favorite dentist of all time was the late Dr. William Currie. He honed his skills as a military man during world war 2. First, he didn’t come on as a health scold; rather he treated the patient as a co-conspirator in the tooth game.
    He quickly zoned in on what topics of conversation would interest the patient and always managed to find some amazing incident to relate.
    Now suppose it is time for him to insert the needle into your gums to anesthetize the mouth. He’s been palming the hypodermic and saying interesting things so you don’t suspect what is coming. Now, suddenly he directs your attention to some crazy thing as he inserts the needle. You don’t feel a thing or even realize what is happening.
    Once I realized how skillful he was, I studied how he did his tricks, and never have been satisfied with any of the subsequent dentists, who were uniformly awful, albeit skillful restorationists. So when the last one told me to eat a low-fat diet, I remained quiet and marvelled at the stupidity.

  5. Though diet is thought to be the primary source of tooth decay, but whatever the diet, it should probably include fluoridated water. By itself, it is reported to reduce the occurrence of cavities by at least 25% and up to 40%-65% in certain populations.

  6. Jim Jozwiak

    I got the man’s name wrong. He was Dr. William R. Curry DMD.

  7. Informative post! But maybe it’s not true for the idea of dentist didn’t tell because it’s their duty to do so. They should to. But you do make a clear point.