Why Cranberry Juice Prevents Urinary Tract Infections

Though never fully scientifically explained in the past, many people, including some doctors, recommend drinking cranberry juice as a measure to prevent urinary tract infections. The explanation for this positive effect has recently been explained by researchers, validating the simple approach.

In addition to helping prevent urinary tract infections, cranberries and cranberry juices are known to have numerous health benefits. They are loaded with antioxidants, which recent research has suggested benefits cardiovascular health by limiting free radicals in the blood stream. This also potentially helps prevent cancer and protects the health of ones immune system. Cranberries have also been suggested to help prevent other bacterial infections, such as gingivitis.

The current study found that certain bacteria, when exposed to cranberry juice, underwent a change of “thermodynamic properties.” Specifically, Gibbs free energy and surface free energy were altered. This translated to an inability for the bacteria to attach to cells, which is the mechanism of infections (such as an infection of the urinary tract).

Multiple bacteria strains were tested with cranberry juice, including fimbriae, which is associated with urinary tract infections. According to the study, even small amounts of cranberry juice altered the thermodynamic properties of fimbriae. For other bacteria, such as E. coli that contained no fimbriae, the effect of cranberry juice was negligible. These results were the same for all types of cranberry juice one might find at a grocery store (standard cocktail, 100% juice, and sugar free).

According to study author Dr. Terri Camesano, “our results show that, at least for urinary tract infections, cranberry juice targets the right bacteriahose that cause diseaseut has no effect on non-pathogenic organisms, suggesting that cranberry juice will not disrupt bacteria that are part of the normal flora in the gut.”

The study notes, however, that while small amounts of cranberry juice have a substantial effect of fimbriae, they do not permanently alter their function. In other words, if cranberry juice is only sporadically consumed, the fimbrae will regain the ability to produce infections. “This suggests that to realize the antibacterial benefits of cranberry, one must consume cranberry juice regularly, perhaps daily,” says Dr. Camesano.

Source: Defeat Diabetes Foundation: Comesano, Terri. Dorsey, Michael. Colloids and Surfaces: B news release. July 2008.