Consumer health
Latest Cranberry comment from Dr. Howell in response to the new study out from Barbosa-Cesnik C, et al. (see original blog post: http://bit.ly/hFE6kG)
I am a Research Scientist at Rutgers University and have been studying the effects of cranberry on maintenance of urinary tract health for the past 17 years. I have done many positive studies that show that consumption of cranberry juice prevents certain bacteria from attaching to bladder cells, the first step in the infection process. There are numerous other studies from around the world that also show positive effects of cranberry.
This latest study is just one trial and the results need to be put into perspective and weighed against the other positive clinical trials in which cranberry was effective. There are always going to be a few negative studies that come out, especially when looking at the effects of food products or supplements on health due to formulation differences, etc. These are not single compound drugs, so we should expect some variation in the study results.
The most confounding issue in this study is that the predicted recurrence rate for UTI in the placebo group was 30%; however, it turned out to be only about 15% – much lower than expected. Interestingly, those people in the cranberry group also had a similarly low UTI recurrence rate, which, in most studies would indicate that the juice worked well. So a possible explanation for this, given by the study authors, is that the placebo might have contained something that had some activity in prevention of UTI, as well. Interestingly, there were twice as many gastrointestinal issues reported with those participants that were on the placebo.
The other issue I see is that there was not a fool-proof way to measure compliance (or making sure that the participants actually consumed the products). Compliance was based on participants self-reporting that they drank the products. I think busy college-age students can be a tough demographic to test in clinical trials, especially when they are asked to drink something twice a day. A more fool-proof approach to measuring compliance would be to monitor the production of a cranberry metabolite in the urine.
The bottom line is that there are a number of positive studies on cranberry and if women are currently consuming cranberry products for maintenance of urinary tract health, the results of this one study shouldn’t be a reason for them to change their current management practices.
