Recurrent Urinary Tract Infection Prevention With Biologic Cranberry Extract Intake Standardized in Proanthocyanidins: A Double-blind Clinical Trial

Cranberry juice, fruit (fresh and dried), functional foods, and cranberry dietary supplements are promoted for prevention of urinary tract infections (UTIs) on the basis of their content of cranberry proanthocyanidins (PACs) with "A-type" interflavan bonds. Several clinical trials have assessed efficacy of cranberry-derived products, essentially with cranberry juices, but discordant results have been found. Lack of compliance but mostly lack of standardization in product concentrations can account for the variability among results. Indeed, most clinical trials do not report quantity of PACs. According to most recent studies, quantification of PACs requiring standardized and reproducible methods should be at least 37 mg/day. It can be hypothesized that efficacy of cranberry extract in UTIs prevention among young women can be strongly increased using optimal dosage (standardized to 37 mg/day of PACs). The purpose of this clinical trial study is to assess, among young and sexually active women presenting recurrent UTIs, efficacy of an optimal dose of cranberry extract quantified and standardized to 37 mg/day of PACs, compared to a control dose quantified and standardized to 2 mg/day of PACs on mean number of new UTIs during a 6-month follow-up period.