Effects of a Cranberry, Probiotic, and Vitamin C Supplement on Recurrent Urinary Tract Infections in Children—A Cohort Study

Recurrent urinary tract infections (UTIs) are common in children and may lead to long-term renal complications, especially in those with vesicoureteral reflux (VUR). Concerns about antibiotic resistance and side effects of prolonged antibiotic use underscore the need for safe, non-antibiotic alternatives. This prospective, self-controlled observational study evaluated a standardized combination of cranberry extract (36 mg proanthocyanidins daily), probiotics (<i>Lactobacillus rhamnosus</i> and <i>Bifidobacterium longum</i>), and vitamin C (250 mg daily) in 39 children aged 3-16 years, including a subgroup with mild-to-moderate VUR. UTI recurrence was compared before and after the 12-month study period. The supplement was administered for 6 months, followed by a 6-month observation period. Microbiological analyses assessed pathogen distribution. Safety and tolerability were monitored. The intervention significantly reduced UTI recurrence, with median episodes decreasing from 3 to 0 in children without VUR (<i>p</i> < 0.001) and from 2 to 0 in children with VUR (<i>p</i> < 0.05). Overall, 27 of 39 participants (69.2%) remained infection-free throughout follow-up, while the remaining participants experienced a reduced number of UTI episodes compared with the pre-supplementation period. <i>Escherichia coli</i> remained the predominant pathogen, while the diversity of other uropathogens changed minimally, indicating fewer infections rather than microbial shifts. The supplement was well tolerated, with mild gastrointestinal symptoms in 5 of 39 participants (12.8%) and no serious adverse events. Subgroup analyses showed consistent benefit across age and sex, with children having higher baseline UTI frequency experiencing the greatest reduction. A multi-component supplement of cranberry, probiotics, and vitamin C effectively reduced recurrent pediatric UTIs, decreased overall infection burden, preserved <i>E. coli</i> as the main pathogen, and was safe and well tolerated, including in children with mild-to-moderate VUR.