Give thanks for the cranberry, say dental researchers

Families gathered around the Thanksgiving dinner table might consider giving thanks for the bacteria-busting ability of cranberry juice, say dental researchers who have discovered that the beverage holds important clues for preventing cavities.

A team led by oral biologist Hyun (Michel) Koo, D.D.S., Ph.D., at the University of Rochester Medical Center has discovered that the same traits that make cranberry juice a powerful weapon against bladder infections also hold promise for protecting teeth against cavities. Koo found that cranberry juice acts like Teflon® for teeth, making it difficult for the bacteria that causes cavities to cling to tooth surfaces. Stickiness is everything for the microbe Streptococcus mutans, which creates most cavities by eating sugars and then excreting acids that cause dental decay.

“Scientists believe that one of the main ways that cranberries prevent urinary tract infections is by inhibiting the adherence of pathogens on the surface of the bladder. Perhaps the same is true in the mouth, where bacteria use adhesion molecules to hold onto teeth,” Koo said.

Koo’s team also found evidence that cranberry juice disrupts the formation of the building block of plaque, known as a glucan. Like a mason using cement to build a wall brick by brick, bacteria use enzymes known as glucosyltransferases to build dental plaque piece by piece, quickly forming a gunky fortress that covers the tooth and gives bacteria a safe haven to munch on sugar, thrive, and churn out acid. Koo’s team found that cranberry juice prevents bacteria from forming plaque by inhibiting those enzymes and by stopping additional bacteria from glomming on to the ever-growing goo.

“Something in the cranberry juice disarms the pathogens that cause tooth decay,” Koo said.

But don’t even think about running to the juice aisle in the grocery store to prevent tooth decay, Koo said. The sugar that is usually added to cranberry juice can cause cavities, and the natural acidity of the substance may contribute directly to tooth decay.

Instead of advocating mass consumption of cranberry juice, Koo hopes to isolate the compounds within the juice that pack an anti-cavity punch. The substances could then be added to toothpaste or mouth rinse directly. He is working closely with Nicholi Vorsa, Ph.D., a plant pathologist and director of the Blueberry and Cranberry Research and Extension Center at Rutgers, to isolate the compounds in juice that are most protective.

A food scientist turned dentist, Koo became fascinated with research and is an expert on natural substances that can improve oral health. Currently, as an assistant professor in the Eastman Department of Dentistry and a researcher in the Center for Oral Biology, he is focusing on ways to stop the bacteria that ultimately causes cavities. Such research, if successful, would improve the oral health of millions of people worldwide.

Koo’s work with cranberry juice is one of nine projects funded through a special program by the National Institutes of Health to test the berry’s reputed health-enhancing effects. The other projects focus on topics such as urinary tract infections and how the body processes cranberry juice.

“There is a massive number of publications about the effect of cranberries on urinary tract infections,” said Koo, “but there are only few studies on the dental side.”

The cranberry research will be published in the January 2006 issue of Caries Research. Other authors include dentist Patricia Nino de Guzman, dental student Brian Schobel, and microbiologist Anne Vacca Smith, Ph.D., and dental researcher William Bowen, D.D.S., Ph.D.

As Thanksgiving approaches, Koo said that only cranberry juice is under study, so diners shouldn’t reach for the cranberry sauce just to stop the tooth decay brought on by carbohydrate-laden foods like mashed potatoes, rolls, and pumpkin pie. He recommends traditional measures to avoid cavities: Brush your teeth after dinner, don’t snack often, stay away from sugary foods, use a mouth rinse, and get regular dental checkups.