BACKGROUND: High prevalence of urinary tract infections (UTI), including cystitis, and concern for antimicrobial resistance justify safe and effective nonantibiotic therapies for prevention of recurrent UTI (rUTI). OBJECTIVES: This study investigated the effect of a whole cranberry fruit powder supplement on incidence of culture-confirmed UTI (primary outcome) in females with rUTI history. METHODS: This multicenter, 6-mo, randomized, placebo-controlled, double-blind study enrolled 150 healthy females [18-65 y, body mass index (BMI) >
17.5 and <
35 kg/m RESULTS: Whole cranberry powder capsules reduced culture-confirmed UTI risk compared with placebo by 52% (adjusted relative risk [RR]: 0.48
95% confidence interval [CI]: 0.26, 0.87
P = 0.01)
reduced Escherichia coli UTIs (RR: 0.49
95% CI: 0.24, 1.01
P = 0.05)
reduced incidence of UTI with urinary frequency and urgency symptomatology (RR: 0.29
95% CI:0.13, 0.63
P <
0.01)
delayed time to first UTI episode (adjusted hazard ratio [HR]: 0.36
95% CI: 0.18, 0.74
P = 0.01)
and reduced the mean total number of UTIs per participant (adjusted incidence rate ratio IRR: 0.41
95% CI: 0.21, 0.79
P = 0.01). Significant differences between groups in incidence of symptomatic suspected UTIs and culture-confirmed dysuria were not observed. Exploratory scores for UTI-related female sexual matters, assessed in a subset of sexually active, consenting females, did not differ significantly between groups. No safety concerns were reported. CONCLUSION: This study shows that whole cranberry powder capsules do not impact safety markers and reduce the incidence of culture-confirmed UTI and several other UTI-related outcomes in healthy females with rUTI history. This trial was registered at clinicaltrials.gov asNCT03042273.