The bladder receives urine from the kidneys, which it stores until you urinate. It is susceptible to infection by germs that enter through the urethra. This is especially true for women, whose urethra is shorter than that of men, providing a quicker route for bacteria to enter the bladder. Menopause also increases the likelihood that a woman will contract a bladder infection. Cranberry juice and cranberry supplements might reduce your risk of developing a bladder infection, or might speed your recovery from infection. Discuss the use of cranberry with your doctor to determine if it is appropriate for you.
Cranberries
Cranberries are produced by a shrub, Vaccinum macrocarpon, that is native to North America. The fruit was used by Native Americans to treat several disorders, including kidney and bladder problems. The cranberry plant grows in bogs in temperate regions and its fruit is harvested by floating the berries to the surface and removing them by sieving. The berries possess a number of properties that make them beneficial for your health and especially good for your bladder.
Properties
Cranberries contain a number of natural, healthy compounds. They are rich in antioxidants that remove harmful free radicals from your body and they provide lots of vitamin C. In addition, cranberries contain chemicals called proanthocyanidins, compounds that affect the behavior of bacteria, including E. coli, the most common cause of bladder infections. Bacteria exposed to these compounds lose their ability to attach to the cells that line the bladder, preventing them from growing and causing an infection.
Evidence
Several clinical trials have suggested that cranberry juice might prevent infections of the urinary tract. In one of these, published in the "Canadian Journal of Urology" in 2002, subjects who took either cranberry juice or tablets containing cranberry extract experienced fewer urinary infections than subjects who took a placebo. In a trial with children published in 2009 in the "Scandinavian Journal of Urology and Nephrology", girls 3 to 14 years old who consumed concentrated cranberry juice daily had fewer bladder infections than a group that consumed a placebo.
Recommendations and Precautions
Cranberry extract or concentrated cranberry juice is available from health food stores in capsules, generally 300 to 400 mg per dose. Consume up to six doses daily. Alternatively, drink 3 oz. or more of pure cranberry juice daily. Cranberry juice or supplements generally are considered safe and without significant side effects. However, most cranberry juice contains sugar, which should be considered if you are diabetic. The juice also contains oxalates that might contribute to kidney stones in some people. If you have experienced this problem, discuss use of cranberry carefully with your doctor.
References
- MedlinePlus: Cystitis -- Acute
- Memorial Sloan-Kettering Cancer Center: Cranberry
- University of Maryland Medical Center: Cranberry
- "Scandinavian Journal of Urology and Nephrology"; Cranberry Juice for the Prevention of Recurrent Urinary Tract Infections: A Randomized Controlled Trial in Children; P. Ferrara et al.; 2009
- "Canadian Journal of Urology"; A Randomized Trial to Evaluate the Effectiveness and Cost Effectiveness of Naturopathic Cranberry Products....; L. Stothers; 2002
- MedlinePlus: Cranberry
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