Cranberry juice is well-known for treating urinary tract infections (UTIs). Unfortunately, it's effectiveness in treating UTIs isn't backed up by science, as it hasn't been investigated for this purpose. However, the Mayo Clinic states that some evidence exists that suggests cranberry can be useful in preventing UTIs in people who are healthy.
History
Native to North America, the cranberry has been used historically as a food and for medicinal purposes by Native Americans in treating bladder and kidney disease, according to the University of Maryland Medical Center (UMMC). Modern applications extend use of cranberry juice and other supplements for urinary tract infection prevention and treatment, according to the National Center for Complimentary and Alternative Medicine (NCCAM), as well as stomach ulcers and dental plaque build-up. Purportedly, cranberry juice also has antioxidant and anticancer properties.
Properties
According to the UMMC, cranberry was initially thought to make urine more acid, which in turn kills the Escherichia coli bacteria that causes UTIs. The Mayo Clinic reports that cranberry appears to stop this bacteria from adhering to cells that line the bladder, possibly making it effective as a preventive treatment for UTIs. However, the May Clinic goes on to state that "urine acidification does not appear to play a role."
Prevention vs. Treatment
Small studies in humans seem to indicate that cranberry juice and other products may be helpful in preventing UTIs, but NCCAM states that many were not well-designed. According to the Mayo Clinic, existing studies, many of which were sponsored by cranberry juice manufacturer Ocean Spray, examined if cranberry was effective for UTI prevention in various populations, such as healthy women, pregnant women, people with spinal cord injuries and those residing in nursing homes. Although no one study points to cranberry as an effective way to prevent UTIs, the body of scientific evidence seems to give cranberry juice the benefit of the doubt. Cranberry juice has not been examined as a treatment for existing UTIs, according to NCCAM.
Use
Cranberry juice is safe enough for pregnant women to drink, according to the UMMC. Suggested amounts of cranberry juice for adults is 3 or more fluid ounces (around 10 oz. cranberry juice cocktail). Alternately, you can eat 1.5 oz. of fresh or frozen cranberries or take 300 to 400 mg of cranberry capsules each day. Children with UTIs should always be treated by a doctor, notes the UMMC.
Cautions
Although no serious side effects are associated with cranberry juice, the UMMC states that people with kidney stones should talk to a doctor before drinking a lot of it, as it can increase the risk of kidney stone formation. If you have diabetes, look for cranberry juice that's artificially sweetened. Cranberry juice can interfere with warfarin, a blood-thinning medication. If you take this medication, limit your cranberry juice intake, advises the UMMC. Oral antibiotics are the first line of treatment for UTIs, according to the Mayo Clinic. Cranberry juice should never be used as a substitute for medical treatment.
