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Cranberries for UTI? Maybe Not

Thanksgiving Day is just around the corner.  Like others, I’m already anticipating a scrumptious feast including turkey, stuffing and of course, cranberry sauce!

But cranberry producers in Massachusetts might not be pleased with the results of a recent study suggesting cranberry products are really not effective at treating or preventing a UTI (urinary tract infection).  The study, published in the Journal of the American Medical Association (JAMA), was conducted by the Yale School of Medicine and evaluated the use of highly concentrated cranberry capsules in 185 elderly nursing home women.  The results showed no difference in the occurrence of bladder infections amongst those given the cranberry capsules vs. those given placebo. 

The results were disappointing as both patients and some medical professionals have often looked to cranberries as a natural alternative to antibiotic treatments.  “I was hoping it would work,” said Dr. Manisha Juthani-Mehta, a lead author of the study and a disease specialist and professor from the Yale School of Medicine. 

UTIs are a significant health problem with up to 150 million estimated cases per year around the world.  They are more common in women than men, mostly due to the fact that women have a shorter urethra.  In older women they account for upwards of 1.8 million office visits per year.  Typical symptoms associated with a UTI include the need to urinate more frequently, painful urination or cloudy urine.

For many, this latest study has closed the door once and for all on the possibility that cranberries might help treating UTIs.  The study was well designed.  They used what is called a “double blind” process in which the researchers did not know who received the cranberry pills and who received the placebo.   JAMA editorial author Dr. Lindsay E. Nicolle puts her opinion bluntly “Any continued promotion of the use of cranberry products seems inconsistent with the reality of repeated negative studies…clinicians should not be promoting cranberry use by suggesting that there is proven, or even possible, benefit.”

As a pharmacist these results are interesting to me.  This is especially so in light of the fact that there were many seemingly scientific reasons that cranberries or cranberry juice should help.  For example, we know that acidification of the urine can deter the growth of bacteria.  Cranberries contain quinic acid which is converted to hippuric acid inside us, acidifying the urine.  Additionally, cranberries contain proanthocyanidins which we think should help interfere with bacterial attachment to the urinary tract.    However, neither of these otherwise reasonable conclusions seems to actually matter.  Cranberries didn’t help.

Of course, this latest study isn’t the first to address the issue of cranberries and UTIs.  Other studies have been done, some which seemed to show some benefits.  But there were often problems with the study design utilized in previous research, leaving room to question the validity of the conclusions.

Nevertheless, there are still things that patients can do to help prevent UTIs.  Staying well hydrated by drinking lots of water is still great advice.  Also, emptying your bladder more frequently seems to help.  And as Dr. Juthani-Mehta points out, in spite of the lack of evidence, “there is little downside to drinking cranberry juice if you like it.” 

But it appears that antibiotics, used judiciously and appropriately, are still the most effective approach to treating urinary tract infections.  Patients with symptoms should see their doctor.

As for me, this latest study will help inform my recommendations about the medical use of cranberry juice and cranberry capsules.  But it certainly won’t interfere with my dinner plans.    So please, have a blessed Thanksgiving, and pass the cranberry sauce when you’re done.