Cranberries help prevent urinary tract infections, but not as well as antibiotics

Eating cranberries to help prevent urinary tract infections is an old home remedy that has stood the test of time. But women who have recurrent urinary tract infections will find more relief from antibiotics, researchers said Monday.

An estimated 30% of premenopausal women develop chronic urinary tract infections. A low dose of the antibiotic trimethoprim-sulfamethoxazole is often prescribed to women who have repeated urinary tract infections in order to prevent recurrences. Typically, however, doctors try to avoid long-term use of antibiotics because it can lead to antibiotic resistance.

Researchers in the Netherlands conducted the first study to directly compare cranberry capsules to trimethoprim-sulfamethoxazole. They assigned 221 women with recurrent infections to take either the drug or cranberry capsules for one year. At the end of the year, the average number of urinary tract infections in the group who took the antibiotic was 1.8 compared with 4.0 in the group that took cranberry capsules.

However, antibiotic resistance emerged as a signficant issue. Antibiotic resistance to the bacterium E. coli was 85% in the antibiotic group compared with less than 30% in the cranberry group.

Moreover, notes the author of an editorial accompanying the study, the dosage and bio-availability of cranberries in the capsules may not have been high enough to produce results. Given the problem of antibiotic resistance, it may be worth more study to see if cranberry supplements can help.

The study is published in the Archives of Internal Medicine.

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