Prior to the current update it appeared there was some evidence that cranberry juice may decrease the number of symptomatic UTIs over a 12 month period, particularly for women with recurrent UTIs. The addition of 14 further studies suggests that cranberry juice is less effective than previously indicated. Although some of small studies demonstrated a small benefit for women with recurrent UTIs, there were no statistically significant differences when the results of a much larger study were included. Cranberry products were not significantly different to antibiotics for preventing UTIs in three small studies. Given the large number of dropouts/withdrawals from studies (mainly attributed to the acceptability of consuming cranberry products particularly juice, over long periods), and the evidence that the benefit for preventing UTI is small, cranberry juice cannot currently be recommended for the prevention of UTIs. Other preparations (such as powders) need to be quantified using standardised methods to ensure the potency, and contain enough of the 'active' ingredient, before being evaluated in clinical studies or recommended for use.
A randomised double-blind placebo-controlled trial to determine the effect of cranberry juice on decreasing the incidence of urinary symptoms and urinary tract infections in patients undergoing radiotherapy for cancer of the bladder or cervix.
Radical pelvic radiotherapy is one of the main treatment modalities for cancers of the bladder and cervix. The side-effects of pelvic radiotherapy include urinary symptoms, such as urinary frequency and cystitis. The therapeutic effects of cranberry juice in the prevention and treatment of urinary tract infections in general are well documented. The purpose of this study was to evaluate the effectiveness of cranberry juice on the incidence of urinary tract infections and urinary symptoms in patients undergoing pelvic radiotherapy for cancer of the bladder or cervix.
                The study was a placebo-controlled, double-blind design. Participants were randomised to receive cranberry juice, twice a day (morning and night) for the duration of their radiotherapy treatment and for 2 weeks after treatment (6 weeks in total) or a placebo beverage, for the same duration.
                The incidence of increased urinary symptoms or urinary tract infections was 82.5% on cranberry and 89.3% on placebo (P=0.240, adjusted odds ratio [cranberry/placebo] 0.48, 95% confidence interval 0.14-1.63).
                The power of the study to detect differences was limited by the below target sample size and poor compliance. Further research is recommended, taking cognisance of the factors contributing to the limitations of this study.
                Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.