A common home remedy for protecting against cystitis has been to drink cranberry juice. The use of cranberries, whether it is through juice, tablets or capsules have been so pervasive that there have even been reports of doctors recommending that patients drink cranberry juice.
However, a recently published review in The Cochrane Library argues that the use of cranberry supplements in general and use of cranberry juice in particular is not very effective for preventing cystitis.
The review considered 24 high quality studies that were either Randomised Controlled Trials (RCT) or Quasi Randomised Controlled Trials (QRCT). Combined together, the studies had a total sample of 4473 individuals. The samples were wide ranging and included children and pregnant women as well as elderly men and women. The treatment groups in the studies had received: either cranberry juice; tablets; or capsules containing the active ingredients. The control groups had received one of various controls such as methenamine hippurate, placebo cranberry products, antibiotics, or lacto bacillus. There were also studies included where the control group had not received any treatment at all.
Overall the findings pointed towards the argument that cranberry juice may have minimal benefits for individuals that had recurring infections. However, the effect was so low that it would require the person to consume at least two glasses of cranberry juice daily and over a long period of time in order to prevent re-infection. In terms of studies using capsules’ or tablets, the findings were less clear as many of the tablets lacked reports of the specific amount of the active ingredient. This made it hard to form a clear conclusion.
The review raised other issues as well. For instance, the attrition rate in studies that were giving participants cranberry juice was high. This led the researchers’ to suggest that drinking cranberry juice over long periods of time might not be acceptable and could affect whether individuals comply with this recommendation in the long term.
Perhaps the most important conclusion to come from this review was that the researchers advocated that there is no further need for research into the effectiveness of cranberry juice to protect from cystitis. We are not surprised, as this issue appears to have had a consistent lack of support from the research community in the past. Research into products that contain derivatives of cranberries may be justified as there is evidence that a compound in cranberries prevents bacteria sticking to the wall of the urethra but whether this can be consumed in sufficient quantities to provide any significant degree of protection is debatable.