A prospective randomized double-blind trial of grape juice antioxidants in men with lower urinary tract symptoms


  • Conflict of Interest: Yes, Grape Juice and Placebo provided by Welch's Food, Inc. (Concord, MA). No other assistance, or access to data or manuscript.

  • Karl-Erik Andersson led the peer-review process as the Associate Editor responsible for the paper.



Many patients take alternative medications for their lower urinary tract symptoms (LUTS) either in addition or as a substitute for traditional therapies, despite a lack of clinical data. Grapes products are hypothesized to improve bladder function due to their antioxidant and membrane-protective actions. There is increasing evidence that progression of obstructed bladder dysfunction is related to bladder ischemia, reperfusion injury and free radical damage. We prospectively studied a standardized grape product on urinary symptoms.


Men >45 years with significant LUTS were randomized to 240 ml daily of either 100% Concord grape juice or placebo. Participants were followed with validated questionnaires for LUTS, erectile dysfunction, and quality of life in addition to PSA, uroflow, and serum and urinary antioxidant levels. The primary endpoint was change in LUTS in Male International Continence Symptom score. The secondary endpoint was correlation between the level of antioxidants and changes in symptom scores.


One hundred thirteen participations were randomized with 96 completing the 3-month follow-up. There was no difference in the primary endpoint between the groups. (ISCmale score improved by a mean of 1.6 points in both groups.) There was no statistical difference between groups by PSA or secondary questionnaires. A statistical significance was found between uroflow rates. Linear regression analysis gave no correlation between antioxidants (serum or urine) and changes in symptom scores or grape juice consumption.


Our study did not demonstrate any difference in LUTS in men taking a daily 240 ml 100% grape juice versus placebo after 3 months. Neurourol. Urodynam. 32: 261–265, 2013. © 2012 Wiley Periodicals, Inc.