Cranberry juice or cranberry capsules are often recommended for both prophylaxis and treatment of UTIs. As cranberry is associated with only mild side effects and is easy available it seems like it would be a good option, but what evidence is there that shows that it is effective?
Whilst there is an abundance of anecdotal evidence to support the use of cranberry for UTIs the scientific evidence is actually quite limited. A Cochrane Review published in 2012 could not recommend cranberry juice as a UTI prevention strategy as it was not significantly better than antibiotics at preventing UTIs and trials were associated with a high drop out rate due to the poor acceptability of drinking cranberry juice.
The Natural Medicines Database notes that there is inconsistent evidence for the use of cranberry products for treating UTIs but that there may be a role for cranberry in preventing UTI. The Therapeutic Guidelines: Antibiotic Therapeutic Guidelines: Antibiotic take a similar position. They state that cranberry has no role in treating UTIs but may reduce the incidence of UTI and of asymptomatic bacteriuria. Both resources point out that the best preparation and dose of cranberry is not clear from the current evidence.
NPS MedicineWise doesn’t recommend cranberry for prevention of UTI, stating that the small benefit that has been demonstrated was in people consistently taking high doses of cranberry. Luckily, they offer plenty of other suggestions to help patients reduce the incidence of UTI. They also provide good prescribing practice advice for health professionals.
Currently it appears the evidence to support the use of cranberry for prevention and treatment of UTIs is limited and conflicting. At this time cranberry should be considered inappropriate as a UTI treatment but as it is not associated with significant side-effects it could be trialled as a preventative strategy. Unfortunately we can’t tell you the best dose or product to use- yet!