American Cranberry (Vaccinium macrocarpon) as a tool for helping with Infection (general)

Background and objective With over 50% of women suffering from at least one episode of urinary tract infection (UTI) throughout their lifetime and an increasing prevalence of antimicrobial resistance, efforts need to be made to clearly identify the evidence supporting potential non-drug interventions. This study aims to compare the effects of cranberry juice, cranberry tablets, and increased liquids for the management of UTIs. Methods PubMed, Embase, and Cochrane CENTRAL were searched for randomised controlled trials. The primary outcome was the number of UTIs, and the secondary outcomes were UTI symptoms and antimicrobial consumption. A risk of bias assessment was performed using the Cochrane risk of bias tool, and the certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation. Key findings and limitations A total of 20 trials (3091 participants) were included, with 18 studies highlighting a 54% lower rate of UTIs with cranberry juice consumption than no treatment and a 27% lower rate than placebo liquid. Cranberry juice also resulted in a 49% lower rate of antibiotic use than placebo liquid and a 59% lower rate than no treatment, based on a network meta-analysis of six studies. The use of cranberry compounds also reduced the prevalence of symptoms associated with UTIs. Conclusions and clinical implications With moderate to low certainty, the evidence supports the use of cranberry juice for the prevention of UTIs. While increased liquids reduce the rate of UTIs compared with no treatment, cranberry in liquid form provides even better clinical outcomes in terms of reduction in UTIs and antibiotic use and should be considered for the management of UTIs. Patient summary With the increasing prevalence of antimicrobial-resistant UTIs, alternate non-drug treatment options for its management are required. Available evidence supports the use of cranberry compounds and increases in fluid intake for managing UTIs.

This Cochrane review of 50 trials (8857 participants) found that cranberry products, whose proanthocyanidins inhibit adherence of p-fimbriated Escherichia coli to the bladder, reduce the risk of symptomatic urinary tract infections in women with recurrent UTIs, in children and in people susceptible to UTIs following interventions.

In a randomized, placebo-controlled, double-blind study, prophylactic cranberry use reduced recurrent uncomplicated cystitis episodes in women, via inhibition of p-fimbriated E. coli adherence to the urothelium, supporting cranberry for UTI prevention.

In a randomized controlled trial, consumption of a cranberry juice beverage significantly lowered the number of clinical urinary tract infection episodes in women with a recent history of UTI, supporting cranberry for UTI prevention.

Cranberry ( Vaccinium macrocarpon ) is a distinctive source of polyphenols as flavonoids and phenolic acids that has been described to display beneficial effects against urinary tract infections (UTIs), the second most common type of infections worldwide. UTIs can lead to significant morbidity, especially in healthy females due to high rates of recurrence and antibiotic resistance. Strategies and therapeutic alternatives to antibiotics for prophylaxis and treatment against UTIs are continuously being sought after. Different to cranberry, which have been widely recommended in traditional medicine for UTIs prophylaxis, probiotics have emerged as a new alternative to the use of antibiotics against these infections and are the subject of new research in this area. Besides uropathogenic Escherichia coli (UPEC), the most common bacteria causing uncomplicated UTIs, other etiological agents, such as Klebsiella pneumoniae or Gram-positive bacteria of Enterococcus and Staphylococcus genera, seem to be more widespread than previously appreciated. Considerable current effort is also devoted to the still-unraveled mechanisms that are behind the UTI-protective effects of cranberry, probiotics and their new combined formulations. All these current topics in the understanding of the protective effects of cranberry against UTIs are reviewed in this paper. Further progresses expected in the coming years in these fields are also discussed.