Urinary tract infections (UTIs) are common, predominantly in women. They often lead patients to consult a general practitioner (GP), who typically prescribes an antibiotic treatment. Over the course of their lifetimes, about half of all healthy women will experience at least one UTI, and 25%-35% of them will have a recurrence within the following year. Recurrent UTIs generally occur within 3 months of the initial infection, even after complete symptom resolution with first-line antimicrobial therapy.
Antibiotic treatment remains the predominant approach for recurrent UTIs. These infections account for 25%-40% of antibiotics consumed in primary care and represent a significant driver of antibiotic resistance. The global rise in antibiotic resistance, particularly of Escherichia coli, has complicated therapeutic choices for UTIs, and the lack of effective oral antibiotics can lead to a growing need for more effective treatments.
D-Mannose is a dietary supplement found in small amounts in some fruits and vegetables. It may offer an alternative approach to antibiotic prophylaxis in women with recurrent UTIs. It is commonly marketed for urinary tract health and could contribute to better antimicrobial management within primary care settings.
Evidence of Efficacy
E coli is responsible for 85% of UTIs. Its adherence in the urinary tract primarily relies on a mannose-sensitive mechanism in which E coli type I pili adhere to mannose structures on the surfaces of uroepithelial cells.
D-Mannose is a monosaccharide naturally found in various plants and fruits (eg, cranberries) and synthesized in the body from glucose for glycoprotein synthesis. Research suggests that free D-mannose in urine could saturate E coli's FimH structures and subsequently block bacterial adherence to the urinary tract epithelial cells. This "competitive inhibition" is considered one of the potential mechanisms to prevent UTIs from developing.
In most studies, the effect of D-mannose has been examined in combination with that of other "nutraceuticals" such as cranberry extract or probiotics. Moreover, there is limited evidence comparing the efficacy of D-mannose supplementation and antibiotics in treating acute UTIs or as prophylaxis. The Cochrane systematic review on the topic concluded that there was insufficient evidence to support D-mannose for UTI prophylaxis. However, an open-label randomized study comparing D-mannose, antibiotic prophylaxis, and usual care without prophylaxis found that D-mannose significantly reduced the risk for recurrent UTIs.
D-Mannose and Prevention
British GPs from 99 primary care centers in England and Wales evaluated the efficacy of D-mannose in preventing recurrent UTIs in 598 women enrolled in a multicenter, randomized, double-blind, placebo-controlled clinical trial. The primary outcome was the percentage of women who had at least one further clinically suspected UTI episode for which outpatient care was required within 6 months of randomization.
Of the 294 women in the D-mannose group and 289 in the placebo group, 150 (51.0%) and 161 (55.7%), respectively, had a further clinically suspected UTI episode (relative risk [RR], 0.92; 95% CI, 0.80-1.05; P = .22). The proportion was similar even in subgroup analyses comparing women with a history of more or less frequent UTIs and premenopausal vs postmenopausal women.
The number of antibiotic cycles prescribed for UTIs did not differ between the two groups.
Participants in the D-mannose group did not consume fewer daily antibiotic doses, and the percentage of women with pathogens resistant to urine culture performed during an infection episode was similar in the D-mannose and placebo groups (13.9% vs 15.6%, respectively; RR, 0.90; 95% CI, 0.60-1.33; P = .59).
Summary
In the context of this pragmatic trial, daily D-mannose did not reduce the percentage of women with recurrent UTIs who had a subsequent clinically suspected UTI.
The controlled design of the study provided results consistent with those of the Cochrane review, where evidence supporting or refuting the use of D-mannose to prevent UTIs in the general population was scarce.
This story was translated from Univadis Italy, which is part of the Medscape professional network, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.