Cranberry Juice Now Unlikely to Prevent Cystitis

Cranberry juice is unlikely to prevent bladder and kidney infections, according to an updated systematic review published in The Cochrane Library.
The authors analysed the most up-to-date evidence and concluded that any benefit, if present at all, is likely to be small and only for women with recurrent UTI.

Urinary tract infections (UTIs) affect the bladder, as in cystitis, and sometimes the kidneys.
Cranberries and cranberry juice have been used to prevent UTIs for decades, although it is not clear how they might help protect against infection.
According to one theory, certain sugars and flavanol compounds in cranberries prevent bacteria sticking to cells lining the walls of the urinary tract.
Several systematic reviews have been published on the subject in The Cochrane Library, each time incorporating more evidence. In the last review in 2008,
it was concluded that cranberries offer a small benefit in preventing recurring UTIs in women.

In the current review, the researchers gathered together evidence from 24 studies that involved a total of 4,473 people. These studies included 14 added since the 2008 update.
Those in treatment groups were given cranberry juice, tablets or capsules, while those in control groups were given placebo cranberry products, water, methenamine hippurate, antibiotics, lactobacillus or nothing.
Although in some studies there were small benefits for women suffering from recurring infections, women would have to consume two glasses of cranberry juice per day for long periods to prevent one infection.
The researchers conclude that current evidence does not support cranberry juice as a means of preventing UTIs.