Why Cranberries Help
Prevent Urinary Infections
BOSTON (AP) -- Scientists believe they have figured out why cranberry juice can help prevent urinary infections: The secret, it seems, is concentrated tannins in the juice, also known as proanthocyanidins.
Urinary infections are a common problem, especially among women, and research has shown that drinking cranberry juice regularly can help prevent them.
Amy B. Howell and others from Rutgers University conducted experiments to understand exactly what in cranberry juice does this. The study was financed by Ocean Spray Cranberries Inc. and published as a letter in Thursday's New England Journal of Medicine.
The test tube studies found that the concentrated tannins from cranberry juice prevent E. coli bacteria, the main culprit in urinary infections, from adhering to the cells that line the urinary tract.
The scientists believe that the substance blocks the growth of the part of the bacteria that is necessary for them to stick to the walls of the bladder and kidney, a crucial step in infection.
Blueberries also contain the concentrated tannins. But many other foods tested, including lemons, oranges, apples, bananas and carrots, do not.
Note - All tannins are not created equal. The tannin in green tea, for example, does not perform that same as the tannin in cranberry. There are unique acids in cranberry tannin not found in other tannins: quinic acid, hippuric acid, and benzoic acid...all of which produce the anti-adherence factor (AAF) which allow the purging of e. coli out of the kidneys and urinary tract.