REDUCTION OF BACTERIURIA AND PYURIA AFTER INGESTION OF CRANBERRY JUICE

Objective.-To determine the effect of regular intake of cranberry juic e beverage on bacteriuria and pyuria in elderly women. Design.-Randomi zed, double-blind, placebo-controlled trial. Subjects.-Volunteer sampl e of 153 elderly women (mean age, 78.5 years). Intervention.-Subjects were randomly assigned to consume 300 mt per day of a commercially ava ilable standard cranberry beverage or a specially prepared synthetic p lacebo drink that was indistinguishable in taste, appearance, and vita min C content but lacked cranberry content. Outcome Measures.-A baseli ne urine sample and six clean-voided study urine samples were collecte d at approximately 1-month intervals and tested quantitatively for bac teriuria and the presence of white blood cells. Results.-Subjects rand omized to the cranberry beverage had odds of bacteriuria (defined as o rganisms numbering greater than or equal to 10(5)/mL) with pyuria that were only 42% of the odds in the control group (P=.004). Their odds o f remaining bacteriuric-pyuric, given that they were bacteriuric-pyuri c in the previous month, were only 27% of the odds in the control grou p (P=.006). Conclusions.-These findings suggest that use of a cranberr y beverage reduces the frequency of bacteriuria with pyuria in older w omen. Prevalent beliefs about the effects of cranberry juice on the ur inary tract may have microbiologic justification.