Study Disputes Efficacy of Cranberries in Preventing UTIs

Results of a recent study offer more evidence against the idea that cranberries can help to prevent urinary tract infections (UTI).

UTIs are a common condition, especially among older women living in nursing homes. In the past, cranberry products have been recommended to help prevent these infectious, but the evidence of their effectiveness has been controversial.
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In order to test the effect of oral cranberry capsules, researchers conducted a randomized, double-blind, placebo-controlled trial involving 185 women aged 65 years and older with or without UTIs at baseline. The women were randomly assigned to receive either two oral cranberry capsules containing 36 mg proanthocyanidin each (total equivalent to 20 ounces of cranberry juice), or placebo.

Main outcomes of the study were the presence of bacteriuria plus pyuria, which was assessed every 2 months over the course of 1 year. Secondary outcomes included symptomatic UTI and all-cause death or hospitalization.

Overall, 147 of the women completed the study and adherence was 80.1%. Unadjusted results showed bacteriuria plus pyuria in 25.5% of the treatment group and 29.5% of the control group. Adjusted results showed no significant difference between the groups or any significant difference in the rates of symptomatic UTIs, death, or hospitalization.

“Among older women residing in nursing homes, administration of cranberry capsules vs placebo resulted in no significant difference in presence of bacteriuria plus pyuria over 1 year,” the researchers concluded.

—Michael Potts

Reference:
Juthani-Mehta M, Van Ness PH, Bianco L, et al. Effect of cranberry capsules on bacteriuria plus pyuria among older women in nursing homes [published online October 27, 2016]. doi:10.1001/jama.2016.16141.