Evidence Level
Moderate
D-mannose has emerged as one of the most promising non-antibiotic approaches for recurrent UTI prevention. The pivotal Kranjčec et al. (2014) RCT of 308 women compared 2g daily D-mannose vs 50mg nitrofurantoin vs no prophylaxis over 6 months. D-mannose reduced UTI recurrence from 60.8% (no prophylaxis) to 14.6%, comparable to the 20.4% recurrence with nitrofurantoin, with significantly fewer side effects. The mechanism is well-established: UPEC type 1 fimbriae with FimH adhesin bind mannose on bladder uroplakin proteins; excess mannose in urine competitively blocks this adhesion. Porru et al. (2014) confirmed similar results in a pilot study using 1g D-mannose three times daily.