Vaccinium macrocarpon, or the cranberry fruit, is native to North America, and it has a long history of herbal and medicinal use documented as far back as the 17th century. The most notable use for cranberry is in treating infections of the urinary tract, including the kidneys and bladder. However, conclusive evidence is variable depending on the dose and the diagnosis. Before using cranberry for urinary tract infections, consult your physician.
Urinary Tract Infections
More than 8 million Americans experience a urinary tract infection, or UTI, in a given year, with women more prone to UTI than men, notes the National Kidney and Urologic Diseases Information Clearinghouse. An infection of the urinary tract develops when bacteria from tiny organisms enter the urinary system and begin to multiply. Bacteria can infect any part of the urinary system, including the kidneys, bladder, ureters or urethra. The farther up the bacteria spread, the more serious the infection and symptoms are, such as painful urination, urgency and frequency. Escherichia coli, or E. coli, are the most common bacteria present in an UTI. Your risk for a UTI increases when you have a compromised immune system or need a catheter for medical purposes. However, sexually active women are prone to UTIs and recurrence, although the exact reason is not fully understood, notes the National Kidney and Urologic Diseases Information Clearinghouse.
Cranberry as an Antibacterial Agent
The initial benefit of cranberry in treating UTI was assumed to be because the fruit acidified urine, notes the "New England Journal of Medicine." However, research indicates the actual benefit of cranberry is the tannin and proanthocyanidin compounds contained in the fruit. These compounds ripen the fruit, giving them color and flavor, but they also serve to protect your body with antioxidant, anti-inflammatory and antibacterial properties. Cranberry coats the walls of your urinary system and acts as a virtual warrior against passing bacteria so that your urinary tract does not accumulate harmful infectious microorganisms.
Evidence of Cranberry to Prevent UTI
The question of drinking cranberry juice daily to prevent any occurrence of UTI is controversial, as noted by the ongoing and contradictory evidence of medical research. According to the American Academy of Family Physicians, early cranberry studies in 1997 concluded that use of extract tablets rather than juice was more effective than placebo in preventing UTIs in adult and elderly women. However, this was not the case for treating children with bladder infections caused by catheters. The AAFP also reported, in a 2001 study with more participants, that cranberry juice was effective in reducing infection risk in women. Unfortunately, a 2011 study reported by the National Center for Complementary and Alternative Medicine indicates that use of 8 oz. of cranberry juice twice a day is not protective against recurrent UTIs compared to placebo, based on a population study of 319 women. The contradictions stem from cranberry for prevention of UTI. Research does agree, however, that evidence does not support use of cranberry alone as a treatment for UTI.
Dosing and Considerations
Whether you should drink or take cranberry daily or not is the real conundrum. It is safe to drink cranberry juice daily to prevent UTI if you are healthy. MayoClinic.com recommends a dose of up to 16 oz. twice a day. However, if you have diabetes or insulin problems, choose sugar-free varieties. If you are prone to kidney stones, do not use cranberry because it may cause stone formation. Do not treat an existing UTI with cranberry without consulting your physician first. To prevent a UTI, use safe sexual and hygienic practices. Drink plenty of water daily to cleanse your urinary system, and talk to your physician if you have urinary system complications.
References
- American Academy of Family Physicians; Cranberry for Prevention of Urinary Tract Infections; Darren M. Lynch, M.D.; December 1, 2004
- National Center for Complementary and Alternative Medicine: Study Shows Cranberry Juice Cocktail is No Better Than Placebo at Preventing Recurrent UTIs
- Science Daily; How Cranberry Juice Can Prevent Urinary Tract Infections; July 25, 2008
- National Kidney and Urologic Diseases Information Clearinghouse: Urinary Tract Infections in Adults
- MayoClinic.com: Cranberry
- New England Journal of Medicine: The Health Benefits of Cranberry
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