Cranberry Juice May Not Help Repeated Urinary Tract Infection

After a first urinary tract infection (UTI) is, one in four of otherwise healthy women experience a recurrence within six months; 5% of women will have multiple recurrences within a year. Cranberry juice is a well-known simple remedy for preventing UTI, possibly because cranberries decreased the adherence of bacteria to the cells lining the urinary tract. However, the effectiveness of cranberry juice in preventing recurrent UTIs has not been adequately studied, although it is a popularly- used remedy. A double-blind, placebo-controlled study done at the University of Michigan, and reported in the journal of Clinical Infectious Diseases, has corrected this omission.

The participants were 319 college women who presented with an acute UTI. They were followed until a second UTI or for six months, whichever came first. Diagnosis was based on a combination of symptoms and urine culture positive for known pathological bacteria. All the participants were randomly allocated to take either 8 ounces twice daily of low-calorie 27% cranberry juice or a placebo juice. Urine samples were taken for culture at baseline, three months, and six months and at visits associated with UTI symptoms.

During the six-month study period there were 54 culture-confirmed recurrent UTI episodes. This gave a recurrence rate of 16.9% overall. The rate was in fact 19.3% in the cranberry juice group and 14.6% in the placebo group, showing a total failure for cranberry juice to demonstrate a decreased likelihood of recurrent UTI.

This finding may contradict some people’s experience of beneficial effects of cranberry juice.  It’s possible that the juice used in the study wasn’t the ideal ‘formulation’ – concentration, etc.  However, if urinary tract infections are recurrent, it’s important to get them treated with the appropriate antibiotics – cranberry juice will just not fix it. . . .