True or False: Drinking Cranberry Juice Can Help Reduce Your Risk of Urinary Tract Infections

mythbuster graphic Thirty percent of women report having had at least one urinary tract infection (UTI), a very uncommon occurrence in men. Although these infections can be effectively treated with medications, for an unfortunate few they have a tendency to recur despite adequate treatment. Can drinking cranberry juice help these women avoid repeated infections?

Evidence for the Health Claim

Most UTIs are caused by coliform bacteria, which live in human feces. Under certain circumstances, these bacteria are able to reach the bladder lining, which normally contains no bacteria, through the urethra (exterior passageway from bladder). Women are far more susceptible to urinary tract infections than men because of their relatively short urethra.
Researchers have found that the chemical properties of cranberry juice interfere with the ability of bacteria to adhere to urinary tract cells, making it more difficult for them to establish an infection. Three acids in cranberry juice are believed to hinder bacterial growth in the urinary tract: citric, quinic, and malic acid.
In one study, researchers measured the number of bacteria adhering to the lining of the urinary tracts of 15 people with spinal cord injuries (a group particularly susceptible to UTIs) for two weeks. During the first week, subjects drank three glasses of water three times a day. During the second week, the same subjects drank eight ounces (236 milliliters) of cranberry juice three times a day instead. The number of bacteria was significantly reduced during the week the subjects drank cranberry juice compared with the previous week.
In another, larger study, researchers compared women who drank cranberry juice with those who did not during a six-month period. Sixteen percent of the the cranberry juice drinkers got UTIs, while 36% of those in the placebo group got the infection.

Evidence Against the Health Claim

Not all studies support the claim that drinking cranberry juice reduces the risk of UTIs. Furthermore, there is little evidence to suggest that drinking lots of cranberry juice once UTI symptoms appear will resolve an acute infection any quicker.
In a review of 24 studies examining the use of cranberry juice in children, researchers found that it may not reduce their risk of urinary tract infections.

Conclusion

There is probably sufficient evidence at this point to recommend cranberry juice as a safe preventive treatment for women who are prone to repeated UTIs. Those who suffer from repeated infections might want to add the juice to their regular diets, having at least one serving daily.
People who drink cranberry juice daily should tell their doctors when they are prescribed antibiotics. Some studies have suggested that cranberry juice may inhibit the effectiveness of some commonly prescribed antibiotics, including amoxicillin and cefaclor .

References

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McCord H, McVeigh G. Pills may fail, but juice works. Prevention website. Available at: http://www.prevention.com/article/0,5778,s1-1-77-226-2194-1,00.html . Accessed November 5, 2008.

Staff, Tufts University. Can your diet prevent a urinary tract infection? Health and Age website. Available at http://www.healthandage.com/Home/%21gm%3D20%21gsq%3Dcranberry%2Burinary%2Btract%21gid2=2375 . Accessed November 5, 2008.

Urinary tract health. The Partnership for Women’s Health at Columbia University website. Available at: http://partnership.hs.columbia.edu/brochures/urinary%5Ftract.html . Accessed November 5, 2008.

Urinary tract infections in adults. American Urological Association website. Available at: http://www.urologyhealth.org/adult/index.cfm?cat=07&topic=147 . Accessed July 7, 2006.

Why cranberry juice works for UTI prevention? University of Pittsburgh website. Available at: http://www.pitt.edu/~cjm6/s99cranberry.html . Accessed on November 5, 2008.

5/6/2011 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Barbosa-Cesnik C, Brown MB, Buxton M, Zhang L, DeBusscher J, Foxman B. Cranberry juice fails to prevent recurrent urinary tract infection: results from a randomized placebo-controlled trial. Clin Infect Dis. 2011;52(1):23-30.

3/6/2013 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2012 Oct 17;10:CD0001321.