Cranberry juice has been shown to prevent bladder infections, although the exact mecahnism by which this prophylxis happens remain unclear. Scientists speculate that compounds in the juice prevent bacteria from adhering to the lining of the urinary tract.
New findings confirms this theory and shows that compounds called tannins (proanthocyanidins) in cranberries prevent E. coli from adhering to cells in the body in three ways:
They change the shape of the bacteria from rods to spheres.
They alter their cell membranes.
They make it difficult for bacteria to make contact with cells, or from latching on to them should they get close enough.
The researchers suggest that cranberry juice or compounds derived from cranberries may be tapped as an alternative to antibiotics.