For a long time, it was thought that the cranberry (Vaccinium macrocarpon) prevented urinary tract infections (UTI) by altering the pH of the urine, inhibiting the growth of the most common form of infective agent, E.coli.
That idea has not been borne out by research, but the effectiveness of the treatment has been proven.
The new idea and researches are quick to say that they are still investigating the mechanism—in that there are two actions going on.
The cranberry is interacting with the E. coli in the colon, preventing it from moving to the bladder and the proanthocyanidins, one of the phenol compounds that naturally occur in the cranberry, prevent bacteria from adhering to the cells on the walls of the urinary tract by interfering with the small hair-like projections on the outside of the bacteria.
All this is well and good, you say, but what kind of cranberry will help me, the drinks, the juice or the cranberry extract capsules? The latest clinical studies involved the juice and the capsules and they showed an almost identical reduction in the number of UTIs over a 12 month period, around 20%.
The cranberry drinks are mixed with sugar and tend to be diluted with water. This is done mostly for taste, so if you want to use cranberries to help you, and the straight cranberry juice is a bit strong for your taste, the capsules are a perfect alternative.