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In brief: Cranberry juice and urinary tract infections

In brief

Cranberry juice and urinary tract infections

Maybe because it’s so tart and ruby red, cranberry juice certainly seems like it should have medicinal properties. People, especially women, have drunk gallons in the belief that it combats urinary tract infections (UTIs). In test-tube experiments, the particular combination of fructose and proanthocyanidins (the substances responsible for the red color) in cranberry juice seems to reduce the adhesive powers of E. coli and other bacteria. If bacteria can’t “grab” onto tissue, they can’t infect it.

It’s doubtful, though, that cranberry juice could stop an infection once it’s started. And there’s no good evidence from studies that it works as a treatment.

But two credible clinical trials have shown that cranberry juice might prevent UTIs. The newer study, published in the Canadian Journal of Urology in 2002, showed that those who drank three cups of cranberry juice daily (or who took cranberry juice extract pills) for one year had, on average, one less symptomatic UTI than those in the placebo group.

But three cups every day amounts to nearly 70 gallons of cranberry juice a year! Smaller amounts could be effective, but we don’t really know.

Another problem: You can buy low-calorie versions, but most cranberry juice drinks are heavily sweetened to offset the tartness, so they’re high in calories. If you want UTI protection, taking the extract pill might be wiser, easier, and (according to the Canadian study) cheaper.

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Last updated:	August 21, 2006