Bad News for Ocean Spray

Monday, January 24, 2011 // Uncategorized

Cranberry juice has been used for years to alleviate irritation caused by urinary tract infections.  It is also used to prevent them.  There has been conflicting evidence as to it’s effectiveness.  This study exerpted in Journal Watch  suggests that placebo does just as well.

Cranberry Juice Is No Better Than Placebo for Preventing UTIs

Or, alternatively, placebo helped too.  

Cranberry juice for the prevention of urinary tract infections (UTIs) is one of the most durable folk remedies around, but attempts to prove its value have yielded results scattered all over the map. Some researchers have found it is worthless, whereas others have found it to be almost as potent as an antibiotic. 

In a randomized double-blind trial from Michigan, researchers assigned 155 healthy college-age women who sought medical care for UTIs to ingest low-calorie cranberry juice (8 oz twice daily) for 6 months after completion of antibiotic treatment. Another 164 women received placebo liquid carefully formulated to mimic real juice in all ways, except that it contained no proanthocyanidin, the moiety in cranberry juice that is thought to lower Escherichia coliadherence to uroepithelial cells. 

At 6 months, UTI recurrence rates were 19% in the cranberry group and 15% in the placebo group — a nonsignificant difference — with both rates strikingly lower than the expected recurrence rate of 30%. Further, although E. coliaccounted for initial infections in about 80% of both groups, it accounted for far more recurrent infections in the cranberry group than the placebo group (93% vs. 58%) — exactly the opposite of what one might have expected if proanthocyanidin was involved. 

Comment:Here stands another negative study for the cranberry, although this one raises the intriguing possibility that the cranberry’s active ingredient in fact might not be proanthocyanidin but another compound that, in this study, was present in both juice and placebo. And so the strange saga of the little berry that defied science continues. 

Abigail Zuger, MD 

Published in Journal Watch General Medicine January 20, 2011 


Barbosa-Cesnik C et al. Cranberry juice fails to prevent recurrent urinary tract infection: Results from a randomized placebo-controlled trial. Clin Infect Dis 2011 Jan 1; 52:23. (


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