Cranberry juice combats infection

Folk medicine has long suggested that drinking cranberry juice can help fight urinary tract infections. Now a new study has demonstrated the exact physical mechanism involved, proving that cranberry juice really does work.

Most urinary tract infections are caused by a particularly virulent strain of E. coli, which is covered in small hair-like projections known as fimbriae. These act like Velcro hooks to allow the bacteria to attach themselves to the cells that line the urinary tract.

Unlike most studies investigating the health properties of foods, this study focussed on detailing and measuring the exact physical mechanism generated by the cranberry juice. When E. coli is exposed to the juice the fimbriae actually curl up, reducing their ability to attach themselves to human cells.

By using a tiny molecular probe, the scientists were able to mimic the action of the E. coli attaching to the cells. This also allowed them to measure the size of the force needed to pull the bacteria away.

The experiments were then repeated in the presence of cranberry juice of various concentrations. This showed that the ability of the bacteria to attach to the cells was reduced as the concentration increased.

Finally, additional experiments showed that strains of E. coli without the fimbriae did not bind well to the human cells.

These results, published in the journal of Molecular Nutrition and Food Research, show that the presence of cranberry juice in the urine can help dislodge any E. coli present in the urinary tract.

This article was published on Mon 19 July 2010