Q. I recently heard from a friend that she was having frequent bladder infections and didn’t want to take any more antibiotics. She decided to try cranberry pills and found they work great. Her blood pressure is lower, too. What do you know about cranberry pills?
A. Cranberry juice has a reputation for preventing urinary tract infections that goes back decades. Recent research has been somewhat inconclusive (Cochrane Database of Systematic Reviews, Oct. 17, 2012). A recent small study in Wisconsin found that women eating sweetened dried cranberries had fewer infections (Nutrition Journal, online Oct. 18, 2013). Researchers have suggested that using cranberry products to prevent recurrent urinary tract infections might help reduce antibiotic overuse and resistance (Advances in Nutrition, Nov. 2013).
The evidence that cranberry products can normalize blood pressure is even more elusive, but one placebo-controlled study found that double-strength cranberry juice consumed for a month reduced arterial stiffness (American Journal of Clinical Nutrition, May, 2011). That is a benefit, of course, and is probably attributed to the polyphenols in the cranberry juice. We are glad your friend found it helpful but we are not sure it would lower blood pressure for others.
