The use of cranberry powder results in a clinically relevant dose-dependent reduction in lower urinary tract symptoms (LUTS) in men over 45 years of age, according to data published in the World Journal of Urology.

Vidlar et al. carried out a 6-month, randomized, double-blind, placebo-controlled trial to investigate the effect of Flowens™, a cranberry powder formulation, on LUTS and uroflowmetry. 124 men with serum PSA levels <2.5 mg/ml and International Prostate Symptom Score (IPSS) ≥8 were randomized to receive either 500 mg or 250 mg cranberry powder (n = 40 and n = 43, respectively), or a placebo (n = 41), in the form of a capsule. Participants were not permitted to make other dietary or lifestyle changes during the study period, and LUTS were evaluated using the IPSS at baseline, 3 months, and 6 months. Urinalysis, uroflowmetry, kidney and bladder ultrasonography, and blood tests including serum PSA levels were also carried out at baseline and 6 months, with 98.4% adherence to scheduled visits and 100% compliance with the treatment protocol.

At the 6 month timepoint, mean reduction in IPSS was −1.5 for the placebo group, −3.1 for the 250 mg cranberry powder cohort (P <0.05), and −4.1 for those who received the 500 mg dose (P <0.001). Analysis of covariance for IPSS at 6 months showed a significant dose effect (P <0.0001). In the high-dose cohort, the team observed a significant reduction in voiding symptoms at both timepoints, and in storage symptoms at 6 months.

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The authors postulate that the effect might be via effects on detrusor contraction and relaxation, modulation of the micturition reflex, or a reduction in inflammation.

Larger, multicentre trials are needed to confirm these results before Flowens™ is recommended for the amelioration of LUTS in symptomatic men.