Xylitol, or birch sugar, is a sugar naturally found in plums, strawberries, raspberries, and rowan berries. It is often used to sweeten toothpaste and chewing gum since it is as sweet as sucrose but does not cause tooth decay; this is because it cannot be fermented by bacteria that live in our mouths, and instead inhibits their growth. As the key step causing acute ear infections is the colonization of the middle ear by bacteria that move there from the mouth, researchers have hypothesized that xylitol might help prevent acute ear infections as well as tooth decay.
Researchers at the University of Toronto recently performed a meta-analysis of three Finnish studies and found that children who chewed gum — or took other products laden with xylitol, including lozenges or syrup — had about a 25% lower risk of developing an ear infection compared to controls. The study is published in the Cochrane Database of Systematic Reviews .