Abstracts

Popular natural remedy for men’s urinary symptoms works no better than a placebo

Extract of fruit from the saw palmetto palm tree is thought to improve urinary symptoms caused by benign prostatic hyperplasia. Saw palmetto extract is popular, but there is little evidence that it works, despite a series of more than two dozen increasingly rigorous trials and at least two meta-analyses. Reasoning that the lack of effect might be the result of inadequate dosing in previous trials, researchers designed a trial that tested double, then triple, the standard dose against an identical-looking placebo in 369 men with lower urinary tract symptoms typical of benign prostatic hypertrophy.

The extract had no effect at any dose, at any time, or for any subgroup. Symptom scores fell slightly in both groups during the 72-week trial. Men given palmetto extract started on the standard dose in a single capsule, added a second capsule at week 24, and a third at week 48. Even the highest dose had no impact on quality of life, nocturia, or any other secondary outcome.

Participants had a mean age of 61 and a mean symptom score of 15 (out of a possible 35) at the start of the trial. The researchers excluded men whose serum concentrations of prostate specific antigen were more than 10 µg/l and any who had recently taken drugs for benign prostatic hypertrophy.

Barry MJ, et al. JAMA 2011;306:1344-1351.