Something for Cavity-Fighters to Chew On

The concept of dental decay as an infectious disease can be difficult to grasp. That a substance derived from a birch tree and found in chewing gum might reduce the chances of moms passing this infectious tooth destroyer to preschoolers may sound even more bizarre.

Yet that was the finding of a Finnish study published earlier this year in the Journal of Dental Research that found that 5-year-olds of gum-chewing mothers had 70% less tooth decay than non-chewing mums.

How is this so? The explanation involves the bacteria S. mutans, a ubiquitous resident of the mouth that, when combined with sugar and bits of stray food, produces the sticky, acid-producing plaque that clings to and erodes the tooth’s enamel coating, creating cavities and decay.

When mothers chewed gum, it stopped S. mutans in its tracks. The levels of the bacteria in their mouths declined, making them less likely to pass it on to their children through usual parental contact--kissing, food-sharing and using their mouths to clean pacifiers before popping them back in their babies’ mouths.

But it was not just any chewing gum that was working its magic in these moms, nor were the benefits restricted to young children, according to the study led by Eva Soderling, a researcher at Turku University in Finland. The specific gum ingredient responsible for reducing transmission of S. mutans is called xylitol, a sweet-tasting compound present in yellow plums, cherries and strawberries. Industrial sources of this bulk sweetener come from birch trees grown in the United States and Europe, where scientists at the World Health Organization have long appreciated its decay-fighting benefits.

These benefits are now receiving more widespread recognition. Catherine Hayes, assistant professor at the Harvard University School of Dental Medicine, recently reviewed the protective effects of xylitol for a dental conference in Bethesda, Md. After a review of the available data, Hayes concluded that dentists and the public should be made aware of the potential decay-fighting properties of xylitol gum.

According to Hayes, the gum’s effect goes “beyond other sugar-free gums containing sweeteners, such as sorbitol, which are promoted for general dental hygiene.”

It may be a little difficult, however, to find xylitol in chewing gums at your local store. Check the labels on packaged gum carefully for this odd-sounding sweetener. Some companies plan to add xylitol to sugar-free candies, mouthwashes and even toothpaste.

Amanda Ursell, a dietitian, is a London-based freelance journalist who writes about food and nutrition.