(HealthDay News) – For some individuals, use of cranberry-containing products appear to protect against urinary tract infections (UTIs).

Chih-Hung Wang, MD, of the National Taiwan University Hospital in Taipei, and colleagues conducted a systematic review and meta-analysis of 13 randomized controlled trials involving 1,616 subjects. The trials compared prevention of UTIs in users of cranberry-containing products versus placebo or non-placebo controls.

The researchers found that, after exclusion of one outlier study, the random-effects pooled risk ratio (RR) for cranberry users was 0.62 compared with nonusers, with moderate heterogeneity (I² = 43%). Cranberry-containing products were found to be more effective in women with recurrent UTIs (RR, 0.53); in women (RR, 0.49) and children (RR, 0.33); in cranberry juice drinkers compared with those who used cranberry capsules or tablets (RR, 0.47); and in people who used cranberry-containing products more than twice per day (RR, 0.58).

“In conclusion, the results of the present meta-analysis support that consumption of cranberry-containing products may protect against UTIs in certain populations,” the authors write. “However, because of the substantial heterogeneity across trials, this conclusion should be interpreted with great caution.”

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