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.
Efficacy of cranberry in prevention of urinary tract infection in a susceptible pediatric population.
The objective of the study was to evaluate liquid cranberry products as prophylaxis against bacterial urinary tract infection in a pediatric neuropathic bladder population. Forty cases managed by clean intermittent catheterization with or without pharmacotherapy were enrolled in a randomized single-blind cross-over study. Subjects ingested 15 mL/kg/day of cranberry cocktail or water for six months followed by the reverse for another six months. Initial catheter urine samples and subsequent monthly and interim cultures were obtained. Associated symptoms were recorded along with follow-up attendance/compliance registry. The number of negative culture months to the number of months contributed was tabulated and compared between interventions. Individual, cumulative and antimicrobial subset analysis was performed. Twenty one patients completed the study;12 dropped out for reasons related to the cranberry (taste, caloric load and cost); seven patients dropped out for other reasons (parents too busy, death, no stated reason). Wilcoxon matched-pairs Signed-ranks analysis revealed no difference between intervention periods (2-tailed P=.5566 [whole group]; p=.2845 [antimicrobial subset]) with respect to infection. Fewer infections were observed in nine patients taking cranberry juice and in nine patients given water; no difference was noted in three. Liquid cranberry products, on a daily basis, at the dosage employed, did not have any effect greater than that of water in preventing urinary tract infections in this pediatric neuropathic bladder population.