Several years ago a study came out giving credence to a bit of folk wisdom: Cranberry juice can fight urinary tract infections. Harvard researchers looked at two groups of elderly women whose urine contained bacteria and white blood cells -- signs that an infection might be developing.
One group drank 10 ounces of cranberry juice a day while another had a drink that looked and tasted like cranberry juice but actually contained none.
After about six weeks the percentage of cranberry juice drinkers with bacteria and white blood cells dropped and remained low for the six months of the study.
Many have assumed that it is the acid in the cranberry juice that reduces the risk of infection. But those who drank cranberry juice actually had urine that was less acidic than those drinking the placebo.
Researchers theorize that a substance in cranberry juice -- and also in blueberry juice -- keeps bacteria from clinging to the wall of the urinary tract.