The Journal of the American Medical Association, JAMA, published in its recent issue a clinical trial on saw palmetto (Serenoa repens) which was funded by the American government’s National Institutes of Health (NIH): Barry et al. Effect of Increasing Doses of Saw Palmetto Extract on Lower Urinary Tract Symptoms JAMA. 2011;306(12):1344-1351.
In this randomized, double-blind, placebo-controlled, multi-center clinical study 357 patients suffering from problems with urination were treated for 1 1⁄2 years either with a saw palmetto extract (produced by Rottapharm/Madaus) or placebo. The usual dosage of 320 mg. per day of the saw palmetto extract was doubled (at 24 weeks) and later tripled (at 48 weeks) during the treatment period (total 72 weeks).
At the end of the trial none of the measured parameters, such as symptoms assessed with questionnaires nor urinary flow rates, changed significantly between the saw palmetto and placebo groups. The study looks well designed and statistically sound, but it has one significant flaw: The patient selection.
The authors write in the discussion of the publication, “...a greater percentage of men in our study...may have had LUTS (lower urinary tract symptoms, i.e., urinary problems) due to causes other than BPH.” This is highly important and relevant to understanding the trial’s negative outcomes. At the outset of the trial, the men’s diagnosis for BPH (benign prostatic hyperplasia, the treatment of symptoms of which are the primary acknowledged indication for saw palmetto extracts) was based solely on observed symptoms. More specifically – and this is particularly significant in a study of this importance -- neither ultrasound imaging of the prostate to determine its size nor rectal palpation (i.e., digital rectal exam) was carried out to confirm the diagnosis.
Patients included in the trial had a low average PSA (prostate specific antigen) value with a large standard deviation of 2.07±1.78. PSA level is strongly correlated to the prostate size and this low value indicates that the majority of the patients might not be affected by BPH at all.1,2 A further inclusion criterion confirms this finding: the initial maximum urinary peak flow rates were rather high with 14.9 ml/s, a value which corresponds to a normal population with only minor BPH symptoms.3 A value of 10ml/s usually better represents patients affected by BPH.
The negative outcome of this trial is in contrast to the beneficial results the majority of BPH patients experience with a saw palmetto berry preparation of good quality. In our own clinical trials with our saw palmetto extract Prostasan® the BPH symptoms decreased after a treatment duration of 8 weeks between 35- 51%. 4,5
We at Bioforce are thus still convinced that standardized saw palmetto berry products are a beneficial and safe treatment for the urinary symptoms of mild to moderate BPH, which has been reflected by everyday use and clinical experiences for more than 40 years. 6
1 Roehrborn et al. Urology. 1999;53(3):581-9..
2 Girman et al., Urology. 1994;44(6):825-31.
3 Overland et al., Eur Urol. 2001;39(1):36-41.
4 Riedi et al., Ars Medici. 2005;2:1-3.
5 Suter at al., study on file, 2011.
6 ESCOP Monograph. Saw Palmetto, 2003; 477-486.