A small study was conducted in 10 Greek postmenopausal women who had at least 3 documented urinary tract infections (UTIs) in the previous year or at least 2 UTIs in the last 6 months prior to the start of the study. Women were given 400 mg of cranberry extract twice per day (2 caps in the morning and 2 in the evening) over 6 months. Urine cultures were taken and proven normal before the start of the study and then every month during the study.
While taking the cranberry extract, none of the women had a UTI over the course of the 6 months and almost all of the urine cultures were sterile (normal). Three women reported mild gastrointestinal problems and their dose was reduced to 2 capsules per day and as a result, their gastrointestinal problems subsided.
Commentary: Cranberries, in the form of juice and capsules have been shown to be effective in previous prevention and treatment of bladder infections. Both cranberries and blueberries belong to the Vaccinium species which are rich sources of dietary flavonoids, including anthocyanins and proanthocyanidins. While the exact mechanism of the benefits of cranberries has not been clearly established, it is thought that the inhibition of adherence of the main bacteria causing infection, Escherichia coli, to the uroepithelial cells that line the wall of the bladder is the main action.
Reference:
Karefilakis C, Mazokopakis E. Efficacy of cranberry capsules in prevention of urinary tract infections in postmenopausal women. J Altern Complement Med 2009;15(11):1155.
