Impact of Cranberry and Ascorbic Acid Supplementation on the Urinary Microbiome of Healthy Women

The sum of microorganisms that colonize the human genital and urinary tract is referred to as the genitourinary microbiome. Urinary tract infections (UTIs), which predominantly affect women, are linked to alterations in the genitourinary microbiome. Cranberries, rich in proanthocyanidins, and ascorbic acid (vitamin C), known for its urinary acidification properties, are commonly used for UTI prevention. However, their impact on the genitourinary microbiome remains poorly understood. This pilot study aimed to assesses the genitourinary urinary microbiome composition in healthy women and evaluates the influence of cranberry and ascorbic acid supplementation. In a randomized, controlled, open-label trial, 27 healthy women in their reproductive age (18 to 40 years) were assigned to three groups: cranberry (8), ascorbic acid (10), and control (9). Urine samples were collected at three time points and processed for 16S rRNA gene amplicon-based microbial community composition analysis. Microbiome composition was compared within and between groups, and between study visits. The genitourinary urinary microbiome was predominantly composed of Lactobacillus spp., reflecting similarities to vaginal flora. No significant shifts in microbial composition were observed in response to cranberry or ascorbic acid supplementation, and no statistically significant differences were detected between the intervention and control groups or between study visits. Sequencing was performed at the Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna under the project ID JMF-2004-2.