Dr. Chih-Hung Wang of National Taiwan University Hospital and National Taiwan University College of Medicine and colleagues conducted a meta-analysis of 13 trials, involving 1,616 subjects -- identified for qualitative synthesis from 414 potentially relevant references. Ten of the trials were further analyzed in quantitative synthesis.
Urinary tract infections are bacterial infections common in adult women.
"Cranberry-containing products tend to be more effective in women with recurrent urinary tract infections, female populations, children, cranberry juice drinkers and people using cranberry-containing products more than twice daily," the study authors said in a statement. "The results of the present meta-analysis support that consumption of cranberry-containing products may protect against urinary tract infections in certain populations. However, because of the substantial heterogeneity across trials, this conclusion should be interpreted with great caution."
The review, published in the Archives of Internal Medicine, noted cranberry juice was found to be more effective than cranberry capsules or tablets in subgroup analysis. Since the volume of cranberry juice may influence the incidence of urinary tract infection, this result might be because subjects drinking cranberry juice were better hydrated than those taking cranberry capsules or tablets, the researchers said.