Cranberry in the form of juice and supplements is used to prevent urinary tract infections, but it is not used to treat urinary tract infections (UTI) that are already established. With a qualified health care provider's approval, cranberry may be taken alongside prescription medication to cure a UTI and continued as a preventive measure when the infection is resolved.
Types
Pure unsweetened cranberry juice; cranberry juice cocktail; and cranberry tablets and other types of supplements made from cranberry extract, dried cranberries or dried cranberry juice are used to help prevent urinary tract infections. Cranberry tablets are just as effective as cranberry juice in preventing UTIs, according to a study published in a 2007 issue of "Phytomedicine."
Significance
With a health care provider's guidance, women and others who suffer from recurrent UTIs may be able to reduce the number of infections by using cranberry juice or cranberry tablets as preventive therapy. Although UTIs are most common in women, men--especially older men--are also susceptible and may benefit from using cranberry.
Effects
Exactly how cranberry juice or tablets help to maintain urinary health is unclear. It was once thought that cranberry maintains urinary health by creating an acid environment in the urine that repels bacteria, but this is no longer considered true. The current thinking is that cranberry significantly decreases the number of E. coli and other bacteria that stick to the walls of the bladder, where they might otherwise accumulate, reproduce and cause infection, as confirmed by a study, using cranberry juice cocktail, performed by researchers at the Worcester Polytechnic Institute and published in a 2010 issue of Molecular Nutrition & Food Research.
Dose
There are no official dosing guidelines for cranberry juice or cranberry supplements, according to the National Institutes of Health, but since both forms of the berry are considered safe to consume, it suggests that healthy people drink moderate amounts, or 10 ounces a day, of cranberry juice cocktail to prevent UTIs. The NIH also reports that doses between one and six, 300 to 400 mg capsules of hard gelatin concentrated cranberry juice extract, with water before or at least two hours after meals, have been used in scientific studies.
Considerations
Since dosing guidelines for cranberry juice, cranberry tablets and other forms of the berry are vague, and different brands vary with respect to strength, quality and recommended amounts, the National Institutes of Health recommends discussing these issues with a qualified health care provider before taking cranberry tablets or drinking cranberry juice as a therapy to prevent urinary tract infections.
Cranberry is not a treatment for established urinary tract infections, but it may be used as an adjunct therapy with antibiotics prescribed for this condition. Again, speak with a doctor or other qualified health care practitioner to find out if cranberry in any form is right for you.
References
- National Center for Complementary and Alternative Medicine: Cranberry
- Molecular Nutrition & Food Research: Direct Adhesion Force Measurements Between E.coli and Human Uroepithelial Cells in Cranberry Juice Cocktail
- National Institutes of Health/MedlinePlus: Cranberry
- Phytomedicine: Can a Concentrated Cranberry Extract Prevent Recurrent Urinary Tract Infections?
- Penn State University: Urinary Tract Infections
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