MONDAY, July 9, 2012 (HealthDay News) -- Cranberry juice and cranberry supplements really do help prevent urinary tract infections, a new study confirms.
As many as 50 percent of women will develop at least one urinary tract infection in their lifetime, and up to 30 percent will develop recurrent urinary tract infections (UTIs), according to the experts. So researchers have long debated what role -- if any -- cranberries and cranberry-containing products play in preventing or treating these painful infections.
For this new report, researchers from Taiwan analyzed 13 studies that compared cranberry-containing products to inactive placebo among a total of 1,616 individuals in North America and Europe. Most of the trials lasted six months.
The result? These longtime folk remedies provide protection against common urinary tract infections, especially among women, women with repeat infections, children, and those who drink cranberry juice instead of talking cranberry supplements, the researchers reported.
In addition, people who consumed the cranberry products twice a day got more protection than their counterparts who did so less frequently, according to the study, published July 9 in the Archives of Internal Medicine.
"Cranberry-containing products could reduce the incidence rate of UTIs for people at high risk," said study author Dr. Chien-Chang Lee, director of the department of emergency medicine at National Taiwan University Hospital Yunlin Branch in Yunlin County.
Pregnant women, the elderly and people with neuropathic bladder -- an underactive bladder caused by damage to the nervous system -- are among those at high risk.
Exactly how cranberries help stave off urinary tract infections isn't fully known, but they may interfere with the attachment of bacteria to cells, potentially preventing infection.
Cranberry juice may be more effective than capsules or tablets. "This benefit might come from the additive or synergistic effect of unknown substances in the juice, which are devoid in cranberry capsules or tablets," Lee said. "Therefore, we recommend cranberry juice rather than cranberry tablets/capsules in prevention of UTIs despite its side effects."
"People taking cranberry juice for a long time might suffer from gastrointestinal upset," Lee said. "Cranberry capsules or tablets might prevent this side effect."
The high sugar content of some cranberry juices might also be a concern for someone with diabetes, the authors said.
Because of many differences in the studies and study populations included in this analysis, the results should be interpreted with caution, the authors added.
Not everyone is sold on the preventive powers of the bog berry. Dr. Elizabeth Kavaler, a urologist at Lenox Hill Hospital in New York City, said that cranberries and cranberry juice may be worth a try for the prevention of urinary tract infections. But "when you have a UTI, you have to treat it with antibiotics," she said.
"People who get UTIs often feel helpless because of no control over when they get one, so if the cranberries make them feel empowered, they are safe," she said. The best way to avoid urinary tract infections is to prime your immune system. This includes eating well, exercising and getting enough sleep.
Dr. Jill Rabin, chief of ambulatory care, obstetrics and gynecology and head of urogynecology at Long Island Jewish Medical Center in New Hyde Park, N.Y., said she has "always recommended" cranberry juice or cranberry products to prevent urinary tract infections. "It makes urine more acidic so it is harder for bacteria to accumulate on the bladder wall," she said.
Rabin agreed that cranberries are not a treatment for urinary tract infections. Also, not everyone can safely consume cranberry juice or pills, including individuals who take blood thinners, she said.
"Check your medications to make sure there are no contraindications," she advised.
Individuals with diabetes and those with compromised immune systems may be more prone to develop urinary tract infections. While there is no surefire way to prevent these infections, showering before and after having sex, and avoiding thong underwear may also make a difference, she said.
The U.S. National Kidney and Urologic Diseases Information Clearinghouse talks about treating urinary tract infections.