Cranberry Juice Bogs Down Urinary Tract Infections
Study finds it flushes bacteria out of a woman's system
TUESDAY, June 18, 2002 (HealthDayNews) -- Two glasses of cranberry juice a day should keep the doctor -- and the bacteria -- away.
Preliminary research shows that drinking an eight-ounce glass of cranberry juice in the morning and one in the evening may have a powerful preventive effect against strains of Escherichia coli, which cause urinary tract infections (UTIs). It also reduces rates of antibiotic resistance.
"If you drink cranberry juice and keep it in the system over a 24-hour period, resistant strains of bacteria that get into the system will not be able to set up shop," says Amy B. Howell, lead author of a research letter appearing in tomorrow's issue of the Journal of the American Medical Association. Both regular and low-sugar cranberry juice had the same effect.
The findings are interesting but early, says Dr. James Cummings, chief of the division of urology at Saint Louis University in Missouri.
"I think it's still going to take some more study to move this into a more clinical arena," he says. "They need to look and see why this might work, then they might be able to improve on the idea, or if they can isolate the substance in cranberry juice they might be able to modify it or improve on it, and make it where you could take a pill of whatever the magic substance is."
According to the study authors, UTIs account for some 11 million doctor visits each year in the United States. Worse, many strains of bacteria that cause the infection have become increasingly resistant to first-line antibiotic therapy such as Bactrim, and even to more powerful drugs like Cipro.
"There's a huge level of resistance developing to antibiotics that are used to treat UTIs, and something's got to be done," says Howell, who is also a research scientist at the Marucci Center for Blueberry and Cranberry Research at Rutgers University in Chatsworth, N.J. "Resistance literally has doubled."
In this study, Howell and her colleagues took E. coli from women with confirmed UTIs, then incubated them for 20 minutes in urine from healthy women both before and after these women had consumed 240 milliliters of commercial cranberry juice cocktail. Sixty-two percent of the bacteria were resistant to the antibiotic trimethoprim-sulfamethoxazole.
The cranberry juice cocktail prevented 80 percent of the bacteria, and 79 percent of the resistant strains from adhering to the urinary tract walls. The effect persisted for 10 hours. Urine that had been collected before the cranberry juice was consumed had no effect on the bacteria.
Urinary tract infections start when bacteria burrow into the urinary tract walls and stay there. Cranberry juice apparently washes the bugs out of the system before they have a chance to dig in.
"The bacteria was completely disabled and could not adhere," Howell says. "As a preventative, the juice was very effective and will protect you from the problem of not getting an antibiotic that will kill these things off."
Preventing a UTI could literally be as simple as going to the bathroom.
"Bacteria move up into the bladder every day, and the thing that keeps women from having infections is that the urine washes them out," Cummings says. "If the bacteria are prevented from sticking, it allows the woman every time she empties her bladder to clearly get rid of all the bacteria."
Because the juice doesn't actually kill any bacteria, it also doesn't contribute to making more resistant strains.
The findings are especially good news for women who get recurrent urinary tract infections. It's also good news for Ocean Spray, which helped fund the project.
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