Years ago, we were excited when a placebo-controlled trial substantiated the “old wives’ tale” that drinking cranberry juice could ward off urinary tract infections (UTIs) that kept recurring in elderly women (JAMA, March 9, 1994). That study has been criticized, partly because Ocean Spray provided both the cranberry juice and the similar-tasting but cranberry-free placebo. Nonetheless, there are now hundreds of articles in the medical literature dissecting the ability of cranberry juice to prevent urinary tract infections. Here’s one example of recent research that confirms the power of cranberry powder against UTIs (Phytotherapy Research, online Aug. 13, 2015). Some people wonder whether cranberry pills would be just as helpful. That is what this reader wants to know:
Q. I drink two 8-ounce glasses of cranberry juice per day to prevent recurrent urinary tract infections. This seems to do the trick.
But now I am concerned about my blood sugar being too high. If I substitute cranberry pills will I get the same benefit against UTIs as I do with cranberry juice? Does the pill act the same way?
A. We understand your concern. Unsweetened cranberry juice is so tart that it is generally considered unpalatable. As a result, most commercial cranberry juice has a significant amount of sugar or other sweetener. A person with diabetes is wise to be cautious about this beverage.
Will Cranberry Pills Prevent UTIs?
A recent study randomly assigned 160 women undergoing gynecologic surgery to take cranberry extract capsules or a look-alike placebo for six weeks after surgery (American Journal of Obstetrics and Gynecology, Aug. 2015). Since the surgeries involved urinary catheterization, these women were at very high risk of urinary tract infection.
The good news is that the cranberry pills (two capsules twice daily, equivalent to two 8-ounce servings of cranberry juice daily) cut the rate of post-surgical UTI in half. Based on this research, it seems you can switch to capsules with confidence.
What About D-Mannose?
We have also heard from a number of readers who have found that d-mannose supplements can ward off recurrent UTIs. There appears to be little research on this supplement, although one small study found good results from a combination of cranberry and d-mannose along with two probiotic strains of “good” bacteria (Journal of Clinical Gastroenterology, Nov-Dec 2014, Suppl. 1).
