Introduction: Urinary tract infections (UTIs) represent a common and costly public health
issue. The bacterium Escherichia coli is mainly responsible for most uncomplicated UTIs. Cranberry
antibacterial effects have extensively been studied in order to understand the molecular mechanisms of
action of its bioactive components and their clinical benefits against UTIs. In this respect, the present
review aims to critically analyze the current clinical studies that have evaluated the efficacy of supplementing
cranberry products against UTIs in different subpopulations.
Methods: PubMed database was comprehensively searched, using relative keywords in order to identify
clinical trials exploring the efficacy of cranberry supplementation against UTIs.
Results: Current clinical evidence clearly indicates a possible benefit overall from the use of cranberries
against UTIs. Cranberry consumption may prevent bacterial adherence to uroepithelial cells, reducing
UTI related symptoms. Cranberry consumption could also decrease UTI related symptoms by
suppressing inflammatory cascades as an immunologic response to bacterial invasion. The existing
clinical trials have supported substantial evidence that the beneficial effects of cranberry against UTIs
seem to be prophylactic by preventing infections recurrence; however, they exert low effectiveness in
populations at increased risk for contracting UTIs. Moreover, a lack of cost-effectiveness for cranberry
supplementation has been highlighted.
Conclusions: Additional well-designed, double-blind, placebo-controlled clinical trials that use standardized
cranberry products for long study periods are strongly recommended in order to determine the
efficiency of cranberry on the prevention of UTIs in susceptible populations. At present, cranberry
supplementation can safely be suggested as complementary therapy in women with recurrent UTIs.