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Will Cranberry Juice Every Day Keep the Doctor Away (And Prevent Urinary Tract Infections)?

Worst Pills, Best Pills Newsletter article May, 2011

A new study seriously challenges the notion that continuous use of cranberry juice prevents recurrent urinary tract infections (UTIs) in healthy college women.

The study, published in the January 2011 issue of the medical journal Clinical Infectious Disease was a gold-standard, randomized clinical trial funded by the U.S. National Institutes of Health’s National Center for Complementary and Alternative Medicine, involved 319 women recruited from the University of Michigan Health Service...

A new study seriously challenges the notion that continuous use of cranberry juice prevents recurrent urinary tract infections (UTIs) in healthy college women.

The study, published in the January 2011 issue of the medical journal Clinical Infectious Disease was a gold-standard, randomized clinical trial funded by the U.S. National Institutes of Health’s National Center for Complementary and Alternative Medicine, involved 319 women recruited from the University of Michigan Health Service who had presented to the health service with a urinary tract infection. The women were randomly assigned, for six months, either 8 ounces of 27 percent low-calorie cranberry juice cocktail twice daily or 8 ounces of a placebo juice twice daily.

The cranberry juice was supplied by Ocean Spray Cranberries, as was the placebo juice, which was made to imitate cranberry flavor and color without containing any cranberries. The cranberry imitation was a very important step in ensuring a valid study: Participants could not know if they were getting real cranberry juice or the placebo.

The results showed that confirmed, recurrent UTI cases in the cranberry juice group occurred in 19.3 percent of women compared to 14.6 percent for the placebo juice group. The difference between these groups is not statistically significant.

Previous studies have shown cranberries to have some effectiveness in preventing UTIs. For example, the Cochrane Collaboration, a publicly funded consortium that reviews evidence about the therapeutic benefits of various treatments, evaluated cranberries for UTI prevention in 2009 and found that there was some evidence that supported the theory that cranberries prevent recurrent UTIs in women. However, in these studies the researchers and subjects knew what they were receiving, which almost always guarantees a biased result favoring the treatment.

What You Can Do

You should drink cranberry juice if you like the taste, but it may not prevent UTIs.

If you think you have a UTI, contact your health care professional.

Some Symptoms Of Urinary Tract Infections

Not everyone with a UTI has symptoms, but most people have at least some symptoms. These include:

  • Experiencing a frequent urge to urinate.
  • Experiencing a painful, burning feeling in the area of the bladder or urethra during urination.
  • Feeling bad all over — tired, shaky, washed out.
  • Despite an urge to urinate, only passing a small volume of urine
  • Having urine that looks milky or cloudy, even reddish if blood is present.

Normally, a UTI does not cause fever if it is in the bladder or urethra.

Other symptoms include pain in the back or side below the ribs, nausea or vomiting.