“An apple a day…” Not all medical problems require a stateoftheart solution, and it would be nice to think that products from the corner shop could treat a widespread and uncomfortable ailment. Cranberry juice and related products have been touted as a simple solution for urinary tract infections, but Raul Raz, a member of F1000 Medicine, finds little to support this claim.

Urinary tract infections (UTIs) are a common complaint. Between 10% and 20% of women will suffer a UTI at least once, and a third of these will experience it recurrently. Some recent studies support the use of cranberry as a preventative, but Dr Raz, Director of Infectious Diseases at the Technion School of Medicine in Israel, and his associate Faculty Member, Hana Edelstein, advise the medical community that “cranberry should no longer be considered as an effective [preventative] for recurrent UTIs”.

Cranberry contains hundreds of compounds, and it has been difficult to determine which might be responsible for any therapeutic effect, hindering its adoption. Raz and Edelstein point to differences in clinical trial design and the lack of standardization for doses and formulation. There is a range of potential sideeffects including stomach upsets and weight gain. Cranberry can also interact badly with other medicines such as Warfarin, commonly used to treat heart disease.

In any event, up to 55% of patients discontinue cranberry therapy after a short time. It would seem that the public have already voted with their feet.