Drinking cranberry juice has been recommended to decrease the incidence
of urinary tract infections, based on observational studies and a few
small clinical trials. However, a new study published in the January 1
issue of Clinical Infectious Diseases, and now available online, suggests otherwise.
College-aged
women who tested positive for having a urinary tract infection were
assigned to drink eight ounces of cranberry juice or a placebo twice a
day for either six months or until a recurrence of a urinary tract
infection, whichever happened first. Of the participants who suffered a
second urinary tract infection, the cranberry juice drinkers had a
recurrence rate of almost 20 percent, while those who drank the placebo
suffered only a 14 percent recurrence.
“We assumed that we would
observe a 30 percent recurrence rate among the placebo group. It is
possible that the placebo juice inadvertently contained the active
ingredients that reduce urinary tract infection risk, since both juices
contained Vitamin C,” explained study author Betsy Foxman, PhD, of the
University of Michigan School of Public Health in Ann Arbor. She added,
“Another possibility is that the study protocol kept participants
better hydrated, leading them to urinate more frequently, therefore
decreasing bacterial growth and reducing urinary tract infection
symptoms.”
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