If you've had urinary tract infections, or UTIs, you've likely heard about cranberry juice. Cranberry has a longstanding reputation for preventing UTIs, although the evidence is mixed. The good news is that cranberry is safe, and while it doesn't work for everybody, it may work for you. As always, talk to your doctor before beginning any treatment regimen.
UTIs: Not Just a Nuisance
UTIs are common, particularly in women. But men can get UTIs too, especially those older than 50. If you have diabetes or other chronic diseases, you're at greater risk for UTIs, and they can hit your harder. UTIs can become complicated, even dangerous, progressing from bladder to kidney infection or even to urosepsis, a UTI that enters the bloodstream. So it's important to know whether cranberry deserves its reputation.
How Cranberry Works
In theory, cranberry should work against UTI. Cranberries are rich in proanthocyanidins, pigments that block bacteria from adhering to the urinary tract. Cranberry juice is acidic, creating an inhospitable environment for microbes in the urine. And drinking juice helps increase fluid intake, which is always a good idea when it comes to UTIs.
Evidence
Unfortunately, the research as of 2010 is less than perfect. However, the Cochrane collaboration, a respected multinational group that conducts pooled analyses of clinical research studies, combined the best clinical studies of cranberry in the peer-reviewed biomedical literature into a systematic analysis, published in 2009. They pooled results from 10 studies, including four placebo-controlled trials. The Cochrane analysis supports the conventional wisdom: Cranberry, taken daily, helps prevent UTIs.
How to Use Cranberry
The best cranberry regimen for prevention of UTI is unknown. The evidence suggests that both juice and tablets are effective. The most frequently studied "dose" of cranberry juice is 300 mL a day -- about 10 oz. -- of a beverage containing 30 percent cranberry juice concentrate. The dose of tablets studied varies widely. In fact, there's no good data on the ideal dose, in either juice or tablet form. So if you decide to use cranberry, you'll have to settle on the regimen that best suits you, your taste and your budget.
Side Effects and Caveats
All studies of cranberry for UTI have one thing in common: high dropout rates. Some people just don't like it. Others find it too caloric, expensive or hard on their stomach. Overall, cranberry is safe and nutritious. But everyday use may not be sustainable for some.
Cranberry doesn't work for everybody. The Cochrane analysis confirms that young women with recurrent UTIs benefit most, people over 50 get less benefit, and those with bladder diseases or permanent urinary catheters benefit little, if at all. If you already have a symptomatic UTI, cranberry alone won't help.
Conclusion: Give it a Try
The evidence for cranberry in UTI isn't perfect, and not all authorities recommend it. Two things are certain, however. First, there is no data on whether cranberry works for you. Second, cranberry is safe. If you suffer from recurrent UTIs, do your own study. Take account of how many UTIs you've had in the last year. Then give cranberry a try, tracking UTIs and side effects, and see if cranberry helps. There's a good chance you'll find the experiment worthwhile.
References
- "Journal of Medicinal Food"; Role of cranberry on bacterial adhesion; Pinzon-Arango, PA, et al.; 2009
- Online Library: Cochrane Database Systematic Review of Cranberry for Prevention of UTI, 2009
- "Drugs"; Cranberry and Urinary Tract Infections; Guay, DR; 2009
- "Journal of Urology"; Daily cranberry juice for the prevention of asymptomatic bacteriuria in pregnancy: a randomized, controlled pilot study; Wing, DA; 2008
