Cranberries can fight some urinary tract infections

By Amy Norton

NEW YORK (Reuters Health) - A well-known home remedy for urinary tract infections may in fact work for some women, a review of the published research suggests.

Cranberry juice has long been espoused as a treatment for repeat urinary tract infections (UTIs), and research suggests that certain substances in the fruit can hinder bacteria from sticking to the lining of the bladder.

For the current review, Dr. Ruth Jepson at the University of Stirling in Scotland and a colleague looked at whether cranberry products can in fact prevent repeat bouts of the infection.

Analyzing 10 previous studies, they found some evidence that cranberry juice or cranberry supplements may be effective for women who have recurrent UTIs.

However, the benefits for other people -- including the elderly, who are at elevated risk of UTIs -- were uncertain.

The findings are reported in the Cochrane Library, which is published by the Cochrane Collaboration, an international organization that evaluates medical research.

The 10 studies in the review involved a total of 1,049 adults. In some, cranberry juice was pitted against plain water or another type of juice; others tested cranberry tablets against placebo pills.

Overall, the researchers found, the cranberry products reduced recurrent UTIs by one third over a year -- though the benefit was not seen in all studies or for all groups of people.

And although women with recurrent UTIs generally seemed to benefit, it was not clear from the studies how much cranberry juice they would need to drink, or for how long, to prevent the infection.

Still, the findings suggest that cranberry juice might be worth a try for these women, according to lead researcher, Jepson said.

However, she told Reuters Health, that the patients may also want to consider the cost of regularly drinking cranberry juice, as well as the extra calories -- though, she pointed out, low-sugar varieties are available.

As for cranberry supplements, two studies suggested they may work, but there are obstacles to recommending them.

For one, cranberry supplements come in a range of different strengths, Jepson explained, and the optimal dose and duration of use is unclear.

In addition, she pointed out, it's not known whether supplements are equivalent to cranberry juice in the fruit's biologically active substances. Such ingredients might be diminished or destroyed in the manufacturing process.

SOURCE: Cochrane Library, online January 22, 2008.