A 22-person University of Illinois Chicago study found pure cranberry juice slowed plaque regrowth and cut acid production, but researchers say it is too small and short to show cavity prevention.
Researchers at the University of Illinois Chicago College of Dentistry report that pure, unsweetened cranberry juice slowed the regrowth of dental plaque and reduced the acids that bacteria in plaque produce, according to a summary of the work distributed through ScienceDaily. Those acids gradually weaken tooth enamel and contribute to cavities. The study, led by pediatric dentistry professor Christine Wu and published in the journal Scientific Reports, points to proanthocyanidins, natural compounds in cranberries that are known to interfere with how some bacteria, including E. coli, attach to cells, as a possible explanation.
The experiment was small. It involved 22 participants, 14 children and eight adults, who were randomly assigned to swish one of three drinks: 100% unsweetened cranberry juice, a cranberry juice cocktail containing 27% juice and added sugar, or plain water. Plaque that had built up overnight was sampled before the drink, and a second sample was taken from different teeth 30 minutes afterwards. Plaque exposed to the pure juice regrew more slowly than unexposed plaque and produced less acid in both children and adults. Wu said the team deliberately used a product sold in shops rather than a laboratory extract, and the report says orange and apple juice have not shown the same promise in this research context.
The findings should be read cautiously. With only 22 participants and a testing window of 30 minutes, the study cannot show that drinking cranberry juice regularly prevents cavities or improves long-term dental health, and the researchers say larger, longer studies are needed. Wu suggested the juice might one day serve as a functional beverage or occasional mouth rinse, though its tartness is a barrier, and she floated adding a sugar substitute to make it more palatable. Nothing here changes standard advice on brushing, limiting sugar and visiting a dentist, and this report relies on the ScienceDaily summary of the university's material rather than the full paper.
