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.
Evaluation of cranberry supplement for reduction of urinary tract infections in individuals with neurogenic bladders secondary to spinal cord injury. A prospective, double-blinded, placebo-controlled, crossover study.
To determine the effectiveness of cranberry supplement at preventing urinary tract infections (UTIs) in persons with spinal cord injury (SCI).
                A prospective, double-blinded, placebo-controlled, crossover study.
                21 individuals with neurogenic bladders secondary to SCI.
                Favorable or unfavorable response of cranberry supplement vs placebo on urinary bacterial counts and white blood cell (WBC) counts and the combination of bacterial and WBC counts.
                Individuals with neurogenic bladders due to SCI were recruited and randomly assigned to standardized 400-mg cranberry tablets or placebo 3 times a day for 4 weeks. After 4 weeks and an additional 1-week "washout period," participants were crossed over to the other group. Participants were seen weekly, during which a urine analysis was obtained. UTI was defined as significant bacterial or yeast colony counts in the urine and elevated WBC counts (WBC count > or = 10 per high power field) in centrifuged urine. Participants with symptomatic infections were treated with appropriate antibiotics for 7 days and restarted on the cranberry tablet/ placebo after a 7-day washout period. Urinary pH between the cranberry and placebo groups was compared weekly. Data were analyzed using the Ezzet and Whitehead's random effect approach.
                There was no statistically significant treatment (favorable) effect for cranberry supplement beyond placebo when evaluating the 2 treatment groups for bacterial count, WBC count, or WBC and bacterial counts in combination. Urinary pH did not differ between the placebo and cranberry groups.
                Cranberry tablets were not found to be effective at changing urinary pH or reducing bacterial counts, urinary WBC counts, or UTIs in individuals with neurogenic bladders. Further long-term studies evaluating specific types of bladder management and UTIs will help to determine whether there is any role for the use of cranberries in individuals with neurogenic bladders.