Cranberry juice helps prevent urinary tract infections in some people with recurring infections, but there is no evidence that cranberry in any form will cure an existing infection. In a review of studies published in a 2009 issue of the journal "Drugs," University of Minnesota researchers found that cranberry reduced the recurrence of urinary tract infections by 35 percent in young to middle-aged women but not necessarily in other groups. Consult with your doctor to determine if cranberry juice or any other form of cranberry is right for you.
Background
At one time, researchers believed that cranberry juice's ability to prevent urinary tract infections was due to its acidic nature. They thought cranberry made urine more acidic, and that this acidic environment killed the E. coli bacteria that most often causes urinary tract infections. Now it is known that cranberry does not create an environment that kills bacteria. Instead, cranberry prevents infection in some people by preventing bacteria from attaching to the wall of the urinary tract.
Use
Although both men and women of all ages get urinary tract infections, the U.S. Department of Health & Human Services provides physicians with guidelines that recommend using cranberry juice as a preventative measure only for non-pregnant women with recurring infections. If you get more than two urinary tract infections a year, discuss the use of cranberry juice with your doctor. If you already have a urinary tract infection, cranberry juice should not be used in place of an antibiotic or other medication prescribed by your doctor.
Dose
To help prevent urinary tract infections, the University of Maryland Medical Center recommends drinking 3 oz. of pure, unsweetened cranberry juice or 10 oz. of cranberry juice cocktail, or eating 1.5 oz. of fresh or frozen cranberries every day. Their recommendation for cranberry capsules is six times a day, in doses of 300 to 400 mg at a time. Supplement formulas vary however, and as with any new medical or alternative treatment, it is important to speak with your doctor before using cranberries, cranberry juice or cranberry supplements to prevent urinary tract infections.
Side Effects
Although cranberry juice is considered safe for most people, there are conditions under which taking supplemental cranberry in any form may be undesirable or inappropriate. Cranberry juice cocktail is high in calories and cranberries in various forms may cause upset stomach in some people. Cranberries contain oxalates, substances that may promote the formation of kidney stones. Cranberry juice cocktail that contains sugar may not be suitable if you have diabetes or any other condition that interferes with blood sugar regulation in your body. Cranberry juice, or supplemental cranberry in any form, may also interfere with some medications, such as the blood-thinner warfarin.
