Cranberry Juice Better at Fighting Bacterial Infections than Extracts, Study Finds

According to a recent study performed by Worcester Polytechnic Institute (WPI) researchers, cranberry juice is a better way to prevent urinary tract infections (UTIs) than extracts.

The study examined a group of flavonoids found in cranberries called proanthocyanidins, or PACs. It is believed that this ingredient is what makes cranberry juice infection-fighting properties, and as such, PACs have been considered for an effective extract.

The study, however, found that cranberry juice, not the extract of PACs, is far better at preventing biofilm formation (the forerunner of infection).

"What we have shown is that cranberry juice’s ability to prevent biofilms is more complex than we may have originally thought,” reported Terri Camesano, professor of chemical engineering at WPI and senior author on the paper. “For a while, the field focused on these PACs, but the data shows that they aren’t the silver bullet."

Camesano’s team of researchers incubated two different strains of E. coli in the presence of two different mixtures of commercially available cranberry juice cocktail; they also incubated samples of E. coli in the presence of PACs, but not juice.

E. coli is known to be the primary cause of most UTIs, and previous research has shown that cranberry juice has the ability to decrease the strength of the bacteria.

The researchers found that the juice cultures effectively prevented biofilm formation, but the E. coli in the presence of just the PACs had only limited biofilm formation reduction, It also took longer for the PACs to have an eggect on the bacteria.

"Cranberries have been recognized for their health benefits for a number of years, especially in the prevention of UTIs,” the authors wrote. “While the mechanisms of action of cranberry products on bacterial adhesion and biofilm formation are not fully understood…this study shows that cranberry juice is better at inhibiting biofilm formation than isolated A-type cranberry flavonoids and PACs, although the reasons for this are not yet clear."

This study was reported in the paper “Impact of Cranberry Juice and Proanthocyanidins on the Ability of Escherichia coli to Form Biofilms,” which was published online in the journal Food Science and Biotechnology.