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The Truth about Cranberry Juice Preventing Urinary Tract Infections (UTI)

By Jessica Chandler


Gotta go gotta go…not really

            “Excuse me, excuse me, thank you excuse me.”  This is what you say as you pass through the crowd frantically trying to make it to the restroom.  You get there and nothing comes out, or if you do urinate, it is only a couple of drops and that is it.  A few minutes pass and you rush back to the restroom and this time you void your bladder.  You also notice the urine is cloudy, smells bad, and on top of that, it burns.

 [i][i] [ii][ii]  If the above illustration describes you, then you may have a urinary tract infection (UTI).  UTI’s are the result of a bacterial infection of the urinary tract and its organs, including but not limited to the kidneys, the bladder, or the urethra.  They are more common in women as opposed to men and treatment includes a dosage of antibiotics.  But how do you keep it from coming back?  How do you prevent the UTI, altogether?  The National Women’s Health Information Center (2004) offers many suggestions such as urinating when you feel the urge, drink plenty of water, as well as use good hygiene practices on a daily bases.  However, there is one suggestion they do not make, consuming cranberry juice on a regular basis.  Thus, through the examination of a number of clinical trials, this paper will assess the validity of the claim that cranberries, specifically in the form of juice can prevent UTI’s. 




What is so special about cranberries? 

            Cranberries (Vaccinium macrocarpon), according to a National Center for Complementary and Alternative Medicine (NCCAM) 2005 publication, are one of the few fruits native to North America.  With a composition of greater than 80% water, the tart berry contains approximately 10% carbohydrates and other organic compounds.  It purposes as a medicinal antidote first began with practices of Native Americans as Raz, R., Chazan, B., and Dan, M. note in their publication (2004).  Today, it commonly used in sauces, cocktails, and juices.  Cranberries contain three acids:  quinic, malic, and citric (Jepson RG, Mihaljevic L, Craig, J 2003).  The acidicity of this mixture is what researchers once believed allowed cranberry juice to be a safe and effective choice to prevent UTI’s.  However, a number of studies and clinical trials have found this to be untrue.   

[iv][iv]   [v][v]

Quinic Acid                                            Malic Acid




                Citric Acid


What are They Good For?

            While cranberries contain acidic compounds, it also contains a very important organic compound that will be the focus of its preventative power.  Marion et al (2005) found that cranberries and other Vaccinium macrocarpon species (blueberries) contain phenol compounds known as proanthocyanidins.  A phenol is an organic, six-member ring structure with an attached alcohol group.  Proanthocyanindins are a number of these phenols joined together.  The proanthocyanindin, in particular, inhibits the Escherichia coli bacteria from attaching to the lining of the urinary tract.  Escherichia coli or E. coli is the number cause of UTI’s.  In addition to the proanthocyanidin, says Raz et al., fructose also plays an important role in preventing E. coli from attaching to uroepithelial cells (cells that line the urinary tract). 


[vii][vii]   [viii][viii]

          Phenol                                     Proanthocyanidin B2





How does it do that?

            You may be asking this question yourself.  “How does cranberry juice prevent E. coli from attaching itself to the lining of my urinary tract?”  After consulting a number of clinical trials and scientific journals, it was discovered the experts agree on one thing, they are not sure.  However, Raz (2004) and colleagues provide a suggestion.  They propose the cranberries function in two ways.  The first way is by preventing the E. coli from sticking to urinary tract cells.  This occurs, when the proanthocyanidins stop the adhesions (hairlike protrusions that aid in attaching to surfaces) of the E. coli from connecting with the cell lining or receptors.  E. coli bacteria have two type of adhesins, those that are sensitive to mannose—a sugar compound—and those resistant to mannose.  Secondly, it selects for the bacteria strands of E. coli that are found in the stool.  Detail was not provided in regards to how this occurs; however, it can be deduced that by selecting for the bacteria, it prevents it from attaching, therefore, preventing the infection.   


[x] Mannose


Is the Power in the Juice, the Tablet, or the Cocktail?

            There are a number of cranberry containing products on the market, and it is often left in the hands of the consumer to decide which is best.  In number of clinical studies presented by Jepson RG et al (2003), a test of cranberry juice verses cranberry tablets showed them both to be equally effective in preventing UTI’s.  However, a study presented by Raz et al (2004) shows that in a randomized double-blind study, the rate of recurrence in UTI over a 12-month span was 20% in the cranberry juice group and 18% in the tablet group.  Unfortunately, no creditable studies were located to compare the effects of cranberry cocktail to that of juice and or tablets.  Nevertheless, it appears that products containing cranberries are effective in preventing UTIs. 


 Too Good to Be True?

             While the cranberries may be effective in preventing UTI’s, the question now becomes one of safety and cost.  The NCCAM (2005) presents some precautionary measures in regards to the consumption of cranberry juice.  It should be noted that if one believes they have a UTI, they should consult their physician.  No studies exist to support claims of cranberries treating UTI’s.  Excessive use is not recommended as this has the potential to cause gastrointestinal discomfort or diarrhea.  Furthermore, Raz et al (2004) warns about an increased duration of the consumption of cranberry juice, for this can lead to increased chances of urinary or kidney stones.  As far as economic cost are concern, no study examined the effectiveness of particular brands of cranberry juice; thus, one can let their pocketbook be the judge in determining which treatment (juice or tablet) or brand is best.  Nonetheless, a studied  presented by Raz et al, conducted by L. Stothers, suggests that cranberry tablets are “more cost-effective than organic cranberry juice (p. 1418).  In addition, if the taste of cranberry juice is bothersome or the caloric count is of concern, the tablet may be the better option.  


Says Who and Why Should I Believe Them? 

            In 1966, Papas et al. conducted the first clinical study examining the cranberries effects upon the urinary tract.  Since that time, more than a dozen studies have examined various cranberry-containing products.  Each of the trials had different variables (patient population, various medical conditions etc.), yet they were all testing for one thing.  How well do cranberries work?  In an open, randomized, and controlled trial conducted by Kontiokari, T. et al, 150 women were placed into three groups.  One group consumed 50 mL of cranberry-lingoberry juice concentrate (lingoberries are members of the same genus as cranberries, Vaccinium macrocarpon) with the make up being 7.5 g of cranberry concentrate and 1.7 g of lingonberry concentrate.  The other group consumed 100 mL of lactobacillus drink (lactobacillus is a harmless bacteria often found in dairy products, University of Texas-Houston, 1995), and the third and final group had no intervention and served as the control.  At the end of the six-month treatment period, of the 150 women 16 % of the cranberry-lingoberry group, 39% of the lactobacillus, and 36% of the control group had a UTI recurrence more than once.  Kontiokari even showed that after the cranberry group discontinued their treatment because of a halt in product production, their rates of contracting another infection within the next year were still less than that of other groups.  This suggests that cranberries have some residual effect and even work when not being consumed on a daily basis.  


Important Disclaimer

            With the accessibility of the internet today, it is easy for anyone to post materials promoting a product.  This can lead to misinformation.  Therefore, each of the aforementioned studies were conducted by researchers that declared no conflict of interest (i.e. no manufactures of any brand of cranberry containing product funded the studies).  Furthermore, each of the articles used in preparing the information were obtained from creditable journals of medicine or were sponsored by the government.  Hopefully, one will gain from the information that other options are available when faced with UTI’s.  Although cranberries are NOT proven to treat the infections, it is proven effective in preventing them.  Therefore, with some behavior modification and incorporating consumption of cranberries into your diet, you can prevent UTI’s and avoid the cost and hassles that arises from contracting an infection. 




















Jepson RG, Mihaljevic L, & Craig J. (2006). Cranberries for preventing urinary             tract infections (Review).  The Cochrane Library, 3, 1-21.

Kontiokari, T. Sundqvist, K. Nuutinen, M., Pokka, T., Koskela, M., & Uhari, M.             (2001). Randomised trial of cranberry-lingonberry juice and Lactobacillus             GG drink for the prevention of urinary tract infection in women.  British             Medical Journal, 322, 1571-1573.

Marion, E., McMurdo, T., Bissett, L., Rosemary, J., Price, G., Phillips, G., &             Crombie, I. (2005).  Does ingestion of cranberry juice reduce symptomatic                         urinary tract infections in older people in hospital?. Age and Ageing, 34,       256-261. 

National Center for Complimentary and Alternative Medicine. (September 2005).              Herbs at a Glance:  Cranberries.  Washington, DCU. S. Government             Printing Office. 

Office on Women’s Health in the Department of Health and Human Service.

            (October 2004).  Urinary Tract Infection FAQ. Washington, DC:  U. S.             Government Printing Office. 

Papas, PN, Brusch, CA,  & Ceresia, GC (1966).  Cranberry Juice in the treatment   of urinary tract infections.  Southwest Medicine, 47, 17-20.  

Raz, R., Chazan, B., & Dan, M. (May 15 2004). Cranberry Juice and Urinary Tract             Infection.  Clinical Infectious Diseases, 38, 1413-1419. 

Stothers, L. (2002).  A randomized trial to evaluate effectiveness and cost             effectiveness             of naturopathic cranberry products against urinary tract             infection in women.  Canadian Journal or Urology, 9, 1558-1562.  















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