A randomized, double-blind, placebo-controlled trial to assess the bacterial anti-adhesion effects of cranberry extract beverages

Food Funct. 2015 Apr;6(4):1212-7. doi: 10.1039/c4fo01018c.


In this study, we examined the ex vivo urinary anti-adhesion activity of low-calorie cranberry extract beverages in both a pilot study (n = 10) and a randomized, double-blind, placebo controlled clinical trial (n = 59). In the pilot study, subjects consumed a cranberry extract beverage (CEB) or a cranberry extract and juice beverage (CEJB), compared to placebo. Both cranberry beverages utilized a standardized cranberry extract powder at a level equivalent to low-calorie cranberry juice cocktail (LCJC) on a PAC content basis. Clean-catch urine samples collected at baseline and post intervention were tested for anti-adhesion activity utilizing a mannose-resistant human red blood cell hemagglutination assay specific for P-fimbriated E. coli. Results from the pilot study indicated that ex vivo anti-adhesion activity for both cranberry treatments were higher (p < 0.05) than placebo. In the clinical trial, we compared CEJB to LCJC and a placebo beverage. Post-consumption urine from both cranberry treatment groups showed significantly higher (p < 0.05) anti-adhesion activity compared to placebo. There were no differences observed in anti-adhesion activity between CJEB and LCJC, indicating similar bioactivity. Therefore, acute beverage consumption of cranberry extract and/or juice provides ex vivo anti-adhesion activity, which may help to improve urinary tract health.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Bacterial Adhesion / drug effects*
  • Beverages / analysis*
  • Cross-Over Studies
  • Double-Blind Method
  • Female
  • Fruit / chemistry
  • Humans
  • Male
  • Middle Aged
  • Pilot Projects
  • Plant Extracts / pharmacology*
  • Vaccinium macrocarpon / chemistry*


  • Plant Extracts