Cranberry juice may help ward off UTIs

The infections typically occur when bacteria, called Escherichia coli, invade the urinary tract and set up housekeeping along the walls of the bladder or kidneys. Although the urinary system is routinely cleansed of germs through the elimination process, an infection can develop when stubborn bacteria stick to cell walls and begin to multiply.

Urinary tract infections are a nuisance, at best. At worst, they can lead to serious illness and permanent damage to the kidneys and bladder.

With concerns about the overuse of antibiotics and the potential for bacteria to develop resistance to these drugs, attention has turned toward preventing the infections in the first place. One doctor-approved home remedy for warding off urinary tract infections is cranberry juice.

Cranberries have a long history of medicinal use. For hundreds of years, Native American healers have used the fruit to treat bladder and kidney ailments.

Scientists once believed that cranberry juice reduced the risk of urinary tract infections by acidifying the urine, making the bladder and kidneys less hospitable to invading bacteria. Recent research has led to a greater understanding of the protective powers of cranberries.

In the mid-1990s, scientists at Rutgers University isolated compounds called condensed tannins from cranberry fruit. These agents were found to prevent infection-causing E. coli bacteria from attaching to cells in the kidneys and bladder.

Researchers at Tulane University later demonstrated that the condensed tannins in cranberries interfere with the growth of hair-like filaments on the surface of the bacteria. Without these Velcro-like appendages, the bacteria aren’t able to latch on to the cells lining the urinary tract, making them more likely to be flushed out of the body during urination.

Last week, scientists at the Massachusetts-based Worcester Polytechnic Institute reported their findings that tannins in cranberry juice prevent E. coli from forming a slimy substance, called a biofilm. In the body, the biofilm not only protects the bacteria from destruction by cells of the immune system, it may also render antibiotic medications less effective.