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 tablets for the prevention of urinary tract infections in spinal cord injured patients with neurogenic bladder.
Randomized, double blind, placebo-controlled trial with a crossover design.
                To evaluate cranberry tablets for the prevention of urinary tract infection (UTI) in spinal cord injured (SCI) patients.
                Spinal Cord Injury Unit of a Veterans Administration Hospital, MA, USA.
                Subjects with spinal cord injury and documentation of neurogenic bladder were randomized to receive 6 months of cranberry extract tablet or placebo, followed by the alternate preparation for an additional 6 months. The primary outcome was the incidence of UTI.
                Forty-seven subjects completed the trial. We found a reduction in the likelihood of UTI and symptoms for any month while receiving the cranberry tablet (P<0.05 for all). During the cranberry period, 6 subjects had 7 UTI, compared with 16 subjects and 21 UTI in the placebo period (P<0.05 for both number of subjects and incidence). The frequency of UTI was reduced to 0.3 UTI per year vs 1.0 UTI per year while receiving placebo. Subjects with a glomerular filtration rate (GFR) greater than 75 ml min(-1) received the most benefit.
                Cranberry extract tablets should be considered for the prevention of UTI in SCI patients with neurogenic bladder. Patients with a high GFR may receive the most benefit.
                Spinal Cord Research Foundation, sponsored by the Paralyzed Veterans of America.