Cranberry oligosaccharides might help prevent UTIs

According to the U.S. Department of Health and Human Services, about half of all U.S. women will have a UTI sometime during their lives. Doctors usually prescribe antibiotics to treat the painful condition, but this could contribute to the rise of antibiotic-resistant bacteria. To enable better UTI prevention strategies, Christina Coleman, Daneel Ferreira and colleagues from several institutions wanted to identify active compounds from cranberries that end up in urine and potentially keep bacteria from adhering to human cells.

The researchers fed female pigs dried cranberry powder, collected their urine and used chromatography to separate it into fractions of differently sized molecules. Then, they screened the samples for anti-adhesion activity against the E. coli bacteria that cause UTIs. To the researchers' surprise, proanthocyanidins, the compounds previously proposed to be responsible for cranberry's apparent UTI prevention properties, were absent from the active urine fractions. Instead, the researchers detected oligosaccharides called arabinoxyloglucans in those samples. These complex carbohydrates, related to cellulose, are difficult to detect and isolate, which could explain why they hadn't previously been identified as anti-adhesive components of cranberry, the researchers say.