New research casts doubt on the effectiveness of cranberry juice in protecting women against painful bladder infections, or cystitis, BBC News reported.
Cranberry juice has long been thought to alleviate cystitis, a stinging inflammation of the bladder typically caused by a urinary tract infection (UTI).
However, in a review of 24 studies involving nearly 4,500 participants, the evidence indicated cranberry juiced provided “no meaningful protection” against cystitis.
The researchers who conducted the study, from the University of Stirling, in Scotland, said it was previously believed that cranberries may prevent bacteria from sticking to cells lining the urinary tract.
While a few of the studies did show small benefits for women suffering from recurrent infections, the results were not statistically significant. Women would need to drink two glasses of cranberry juice every day to prevent just one infection.
"We can't see a particular need for more studies of the effect of cranberry juice, as the majority of existing studies indicate that the benefit is small at best, and the studies have high drop-out rates,” lead researcher Dr. Ruth Jepson from the University of Stirling told BBC News.