Cranberry Extract A Proven Remedy For Urinary Tract Infections

As a nation we spend more than $2 billion a year to treat urinary tract infections (UTIs)—which also, by the way, affect men. In fact, according to the National Kidney and Urologic Diseases Information Clearinghouse, in 2006 two million men and nearly nine million women were diagnosed with a urinary tract infection.

The most common treatment for UTIs is antibiotics. But concerns about antibiotic resistance, side effects and prevention of recurrent UTIs in susceptible individuals have led to increased research into why cranberry extract may be a better choice. Until recently, it was believed that the acidity of cranberries is what helps prevent and stop UTIs.

According to a new report published in the Journal of Medicinal Food (March 9, 2009) scientists are beginning to understand the mechanism of how the proanthocyandins (the bioactive constituents) in cranberries—and not the acidity as previously thought—help prevent urinary tract infections.

How does a UTI occur?

Adhesion of E. coli bacteria to cells lining the urinary tract is the first step in the development of a UTI, and E. coli is the cause of about 85% of UTIs and 90% of cases of acute kidney infections. The good news is that cranberry extract does a remarkable job of preventing the adhesion of E. coli bacteria to the cells that line the urinary tract.

Researchers at Worcester Polytechnic Institute, in Massachusetts, exposed E. coli grown in culture to light cranberry juice cocktail and cranberry proanthocyandins (PACs) and used atomic force microscopy to measure how the PACs affect the surfaces of the bacteria. They demonstrated that the longer the bacteria were exposed to either the cranberry juice or the PACs the greater the decrease in bacterial attachment.

The authors concluded that this effect was reversible, and that bacteria re-grown in an environment without PACs regained the ability to attach to the surface. The logical conclusion, then, is that individuals who are susceptible to UTIs should add a daily dose of cranberry extract to their health regimen for continuous protection.1

Another recent study compared the effectiveness of cranberry extract with a low-dose of an antibiotic in the prevention of recurrent UTIs in older women. One hundred and thirty-seven women who had two or more antibiotic-treated UTIs in the previous year were given either 500 mg of cranberry extract or an antibiotic for six months. The researchers concluded that although the antibiotic had a very limited advantage over the cranberry extract in preventing recurring UTIs, it had more adverse side effects. Therefore, they recommend that women consider using cranberry extract—a natural, inexpensive and risk-free alternative to antibiotics—to prevent recurring UTIs.2

Most health professionals agree that taking a cranberry extract supplement is a better way to ingest the proanthocyandins than drinking cranberry juice because:

  • You’d have to drink an awful lot of juice to obtain the amount of PACs that you’d get in a supplement, which typically offers 500 mg per dose.
  • A typical 8-ounce serving of cranberry juice contains only 55 mg of PACs.
  • Juice is usually laden with sugar and calories.

Prevention is always better than the cure. So if you are susceptible to UTIs, play it safe and add cranberry extract to your daily health regimen.


  1. Paola A. Pinzón-Arango, Yatao Liu, and Terri A. Camesano Role of Cranberry on Bacterial Adhesion Forces and Implications for Escherichia coli–Uroepithelial Cell Attachment. J Med Food 12 (2) 2009, 000–000 ©Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition.
  2. McMurdo, M., Argo, I., Phillips, G., Daly, F., Davey, P. Cranberry or trimethoprim for the prevention of recurrent urinary tract infections? A randomized controlled trial in older women. J Med Antimicrobial Chemotherapy. Vol. 63 Issue 2 Feb 2009. BJU Int. 2001;87:760-766.