By Pamela Avonne Williams, M.P.H.
Just one thought of cranberries and all sorts of images enter our minds. Traditionally, these berries were used by Native Americans to treat bladder and kidney conditions. Today, whether it is a sauce or a relish, cranberries are a favorite side dish during holiday dinners. These berries have also made their way to our table as juice and foods such as breakfast muffins; or they are dried and mixed with nuts for a quick snack on the run.
Cranberries have also made their way into the world of science. Researchers once believed that cranberries caused urine to become acidic so that bacteria would not adhere to the walls of the bladder. They thought this was the action that kept infections at bay. Now researchers believe it is the deep red coloring of cranberries, called proanthocyanidins that does this job.
A recent study published in the Journal of Medicinal Food supports this idea. Common bacteria known as Escherichia coli or E. coli cause 85% of urinary tract infections (UTIs) and 90% of acute pyelonephritis or rapid inflammation of the kidney caused by bacteria. These bacteria have hair-like structures called fimbriae. Fimbriae are thought to attach to uroepithelial cells or the cells that line the bladder.
Researchers exposed these bacteria to light cranberry juice and to proanthocyanidins. They measured the energy required for the bacteria to adhere to surfaces with an atomic microscopy. Researchers noted that the ability of E. coli to adhere decreased in the presence of juice and proanthocyanidins. Researchers also noted that when either of these was no longer present, the bacteria would adhere to the cells.1
Based on these and other studies, cranberries may benefit UTI sufferers and catheter patients, and in turn, help lighten the expenses of our health care system. Each year, more than $2 billion is spent on health care and treatment of these conditions. If we include cranberries, cranberry products and cranberry supplements in our daily diets, we may help prevent these infections.
E. coli is not the only microorganism that is kept at bay with the use of cranberries. Helicobacter pylori or H. pylori, the main suspect in ulcers, may respond to cranberries in the same way as E. coli. A study published in the Molecular Nutrition Food Research Journal demonstrated that antibiotics plus cranberries can make a difference. One hundred seventy seven subjects consumed cranberry juice twice a day and prescribed antibiotics for two weeks. H. pylori disappeared among 82.5% of the study participants. The researchers also noted that the disappearance rate was higher among females who took antibiotics and cranberry juice – 95.2% than females who took antibiotics alone – 86.8%.2
The Cranberry Institute suggests that cranberries may also be anti-aging. Animal studies are being conducted to determine the antioxidant activity of cranberries and its possible benefits on the brain.3
Adding cranberry foods to your diet may help prevent UTIs and ulcers associated with H. pylori and other benefits that researchers need to confirm. However, eating cranberries or drinking some of these sugar-loaded juices every day may be daunting. Adding a cranberry supplement will help bridge the gap and meet our healthy goals.
- 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.
- Shmuely H, Yahav J, Samra Z, et al. Effect of cranberry juice on eradication of Helicobacter pylori in patients treated with antibiotics and a proton pump inhibitor. Mol Nutr Food Res. 2007 Jun;51(6):746-51.
- Health Research: Anti-Aging. Cranberry Institute. Location: http://www.cranberryinstitute.org/health/antiaging.htm Accessed September 20, 2009