Cranberry capsules more effective in lowering UTI risk than juice

A urinary tract infection (UTI) can be an unwelcome visitor—leaving you with the urge to sprint for the bathroom every few minutes. You may have heard that drinking a large glass of cranberry juice can effectively 'treat' a bladder infection, but is this remedy more fact or fiction?

A UTI is an infection in any part of the urinary system, kidneys, bladder or urethra. They are more common in women and affect more than 3 million Americans per year. Many in the population will turn to sipping on a cranberry juice cocktail to alleviate their symptoms, but, according to a Texas A&M Health Science Center urologist, drinking cranberry juice to treat a UTI is little more than an old wives' tale.

"Cranberry juice, especially the juice concentrates you find at the grocery store, will not treat a UTI or bladder infection," said Timothy Boone, M.D., Ph.D., vice dean of the Texas A&M Health Science Center College of Medicine Houston campus and chairman of the department of urology for Houston Methodist Hospital. "It can offer more hydration and possibly wash bacteria from your body more effectively, but the active ingredient in cranberry is long-gone by the time it reaches your bladder."

With that said, the active ingredient in cranberry (A-type proanthocyanidins or PACs) can block the adhesion of bacteria to the wall of the bladder. "For a UTI to occur, bacteria must adhere to and invade the lining of the bladder," Boone said. "PACs interfere with the bacteria's ability to bind to the wall of the bladder and create an infection."

Unfortunately, PACs aren't present in cranberry juice at all—only in cranberry capsules. "It takes an extremely large concentration of cranberry to prevent bacterial adhesion," Boone added. "This amount of concentration is not found in the juices we drink. There's a possibility it was stronger back in our grandparents' day, but definitely not in modern times."

A study published in the American Journal of Obstetrics and Gynecology did conclude that taking cranberry capsules lowered the risk of UTIs by 50 percent in women who had a catheter in place while undergoing gynecological surgery. "In this study, they took the cranberry itself and put it in a capsule—the equivalence of drinking 28 ounces of cranberry juice. As you can see, it takes a large amount of pure cranberry to prevent an infection," Boone said.

Symptoms of a UTI include increased urge to urinate, pain with urination, pelvic pain or blood in the urine. While they can be self-diagnosed and are often short-lasting, UTIs usually need to be treated with antibiotics. "Sometimes it easy to confuse a UTI with overactive bladder, so it's always best to consult your physician about any adverse symptoms you're having," Boone said. "UTIs may also progress into kidney infections which are much worse."

Treatment of UTIs can be complicated because of the high rates of reoccurrence, and approximately 20 to 30 percent of women will develop multiple UTIs. Another troublesome barrier to treatment is the increasing resistance of bacteria to commonly used antibiotics—enter probiotics.

"In these instances, probiotics were shown to be safe alternative to antibiotics in the treatment of UTIs," Boone said. "There are many benefits of probiotics, although more research still need to be done."


Texas A&M Health Science Center


  1. Amy Howell Amy Howell United States says:

    As a research scientist at the Marucci Blueberry and Cranberry Research Center at Rutgers University in New Jersey, I am pleased to provide a comment about cranberries and urinary tract health.  You are correct when you state that cranberry does not treat UTIs.  In fact, the clinicals show that cranberry consumption can prevent recurrence of UTI, but not treat the infections.  However, cranberry may become a very important choice for UTI prevention, as many of the antibiotics used to treat infections are becoming much less effective due to bacterial resistance.  It is better to prevent infections with a natural alternative such as cranberry and reduce the ultimate need for antibiotics, preserving them for when they are really needed.  

    In 1998, my lab published our discovery in The New England Journal of Medicine that proanthocyanidins (PACs) are active components in cranberries that prevent certain uropathogenic E. coli from adhering to bladder cells.  Since that time, we have published a number of studies on these compounds, including structural characterization, levels in cranberry products, and dose-response for anti-adhesion activity in the urine following consumption of cranberry. Cranberry juice cocktail drinks sold to consumers are normally formulated to contain about 27% cranberry juice.  There are, in fact, PACs in cranberry juice, about 36 mg in a 10-ounce glass of cranberry juice drink.  And this is the amount that has been shown to be effective in clinical trials.  The study you cite in the American Journal of Obstetrics and Gynecology utilized the equivalent of 2 glasses of cranberry juice, however it is very likely that this was 27% juice drink.  This was the only dosage that was tested, so it may be that lower doses of cranberry could have been efficacious as well.  

    The PACs are present in both juice and dried supplements (and even in the dried cranberries), with target dosages at one or two servings per day of the products.  The PACs survive the cooking process so sauces also have bioactive PACs.  Products containing juice or juice-based supplements with about 36 mg of PACs have elicited bacterial anti-adhesion activity in urine.  The encapsulated supplements that are made from juice can be more expensive but appear to work faster than the ones made from the cranberry skins (which are generally cheaper).  

    Three recent UTI clinical studies indicated significant benefits of cranberry consumption in children, with the participants experiencing as much as a 65% reduction in UTIs and subsequent use of antibiotics. In the July 9, 2012 publication of the Archives of Internal Medicine, scientists reviewed thirteen cranberry and urinary tract health trials with 1,616 subjects and concluded that cranberry-containing products are associated with protective effects against UTIs. In addition, the Journal of Infection and Chemotherapy published a randomized clinical trial involving female patients with UTIs suffering from multiple relapses and the impact of cranberry juice.  The results showed that cranberry juice prevented the recurrence of UTIs in a subgroup of this female population with 24-week intake of the beverage.  This is another indication of the positive attributes of cranberries with respect to the urinary tract health.  For more information, there is a review in cranberry which explains the UTI results and also highlights the additional health benefits of cranberry including reducing risk factors for heart disease:

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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