Dental plaque: Unsweetened cranberry juice curbs acid production, small study finds

Unsweetened cranberry juice may act against dental plaque, according to a small U.S. study. Researchers at the University of Illinois Chicago College of Dentistry led by pediatric dentistry professor Christine D. Wu tested it on 22 people – 14 children and 8 adults. Participants were randomly assigned either 100% pure, unsweetened cranberry juice, a juice cocktail with 27% juice and added sugar, or water. The study was published in the journal Scientific Reports, ScienceDaily reported on Oct. 29, 2026.

The researchers first took a sample of overnight plaque from one side of the mouth. Participants then rinsed with water and swished three small amounts of their assigned drink before swallowing. Thirty minutes later, plaque was sampled from teeth that had not been swabbed. Plaque exposed to the pure juice regrew more slowly and produced less acid in both children and adults. The release cites plant compounds called proanthocyanidins, which can interfere with bacterial attachment, as a possible explanation; this was not tested directly.

"It was important to us to conduct these tests with human participants and use products available on the market," Wu said. The conclusions are limited, however: the group was small, and measurements were taken only half an hour after rinsing. Whether regular drinking protects against tooth decay cannot be inferred; Wu says larger, longer studies are needed. The positive results relate to the pure juice – the release gives no figures for the sweetened cocktail or for water.