(NEW YORK) -- For years, cranberry juice has been touted as the natural way to prevent and treat bladder and urinary tract infections (UTI). But a comprehensive review of studies has found the claims have been overhyped.
Certain sugars and a type of enzyme called flavanol found in cranberries have been thought to prevent infections by keeping bacteria from clinging to cells in the urinary tract.
Results from a review of 24 studies that included nearly 5,000 people suggest that cranberry juice may only be helpful in a select few women. Women with recurrent UTIs are the most likely to benefit from the juice. But regular women would need to drink at least two glasses of it a day over a long period of time to prevent an infection, the researchers said.
However, it's unclear whether cranberry-based products, such as pills, may be able to offer more of a benefit than juice.
"More studies of other cranberry products such as tablets and capsules may be justified, but only for women with recurrent UTIs, and only if these products contain the recommended amount of active ingredient," said Ruth Jepson of the University of Stirling in the U.K., the lead researcher of the review.
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