There's been much research debating the pros and cons of drinking cranberry juice as a complementary alternative for treating urinary tract infections (UTI). No doubt, University of Michigan researchers were scratching their heads after learning that a placebo performed nearly as well as cranberry juice in treating UTIs, an unexpectedly goofy result if there ever was one.

For the record, more than 300 college-age women (median age 21) who had tested positive for a UTI were assigned to drink either 8 ounces of cranberry juice or a placebo twice daily for six months or until they experienced a second infection. Although scientists expected a 30 percent rate of UTI recurrence overall, the number was actually low among cranberry drinkers at 20 percent. Even stranger, recurrence levels were even lower among women who drank the placebo, at 14 percent.

The confusion stems from not knowing which ingredient in cranberry juice and the placebo worked to protect more women from UTIs. Scientists assumed it was proanthocyanidin, a class of flavanols found in many plants. Both placebo and cranberry juice contained ascorbic acid, another chemical used to treat UTIs that hasn't worked as well in controlled trials.

Another possible solution: Drinking either juice kept patients better hydrated, forcing them to urinate more frequently, thus reducing their chances for bacterial growth and UTI symptoms.

This isn't the first time we've witnessed the benefit of the placebo effect in action.

Clinical Infectious Diseases, Vol. 52, No. 1, p. 20-28, January 1, 2011

Nutraingredients-USA.com February 4, 2011

New York Times January 31, 2011 Free Subscription Required

EurekAlert December 8, 2010