The Effect of Cranberry Juice on the Presence of Bacteria and White Blood Cells in the Urine of Elderly Women
For generations, a belief has persisted that the ingestion of cranberry juice somehow protects the urinary tract against infection, but until recently no adequately designed large-scale clinical trials had been performed to test this hypothesis. We conducted a randomized, double-blind, placebo-controlled clinical trial to measure the effect of regular ingestion of cranberry juice on the bacterial flora of older women. The study sample consisted of 153 women ( mean age 78.5 years ) who were randomly allocated to an experimental group, which drank 300 ml per day of a standard commercially available cranberry beverage containing 26% juice; the controls were instead asked to drink the same amount of a synthetic placebo drink prepared for this study, which had an identical taste and color, but contained no cranberry product. Both drinks contained the same amount of vitamin C. Urines were collected monthly for six months and tested for the presence of bacteria and white blood cells. Bacteriuria was defined as the presence of ≥ 105 organisms per ml.