Well - Tara Parker-Pope on Health
January 31, 2011, 1:07 pm
Studying Cranberry Juice for Infections
By TARA PARKER-POPE
Hiroko Masuike for The New York Times Cranberries for urinary tract infections?

Cranberry juice is a popular home remedy for treating and preventing bladder infections. But exactly how and why it seems to help remains a scientific mystery, explains Dr. Abigail Zuger.

How can one little berry be so difficult to pin down? For one thing, the cranberry contains more than 200 active substances in addition to vitamin C, citric acid and an array of other acids. The old theory that these acids sterilize the urine by acidifying it has been disproved: It turns out that even after a person chugs several liters of cranberry juice cocktail in one sitting, the urine does not become acidic enough to slow bacterial growth.

But researchers have repeatedly shown that the juice does effectively prevent some species of bacteria from adhering to the cells that line the urinary tract. More to the point, urine from both mice and people who drank modest amounts of cranberry juice also prevented bacterial adherence.