(Austin, Texas) The results of a new clinical trial on the popular herb saw palmetto may confuse the public, especially men with prostate problems, according to the American Botanical Council, a nonprofit herb research and education group. The trial, published this week in the New England Journal of Medicine (NEJM), found no significant differences between a saw palmetto pill and a placebo in men with moderate to advanced prostate problems. [1]

Saw palmetto is an herbal dietary supplement that is widely recognized for its safety and efficacy in treating mild to moderate symptoms associated with benign prostatic hyperplasia (BPH). BPH is a non-cancerous swelling of the prostate gland in older men, resulting in various symptoms associated with the interruption of normal urinary flow.

“Our primary concern with this trial is the relatively advanced condition of the prostate problems in many of the men who were tested,” said Mark Blumenthal, Founder and Executive Director of ABC.

Blumenthal emphasized that the men in this trial experienced moderate to severe symptoms of BPH, although most of the previous controlled trials showing positive results and efficacy for saw palmetto were conducted on men with mild to moderate symptoms of BPH. The men in the trial had scores between 8-35, i.e., moderate to severe BPH, according to the American Urological Association Symptom Inventory (AUASI).

“Most of the official international monographs that recognize the benefits of saw palmetto do so for stage 1 and 2 of BPH, i.e., the mild to moderate range of BPH symptoms,” said Blumenthal. “These include monographs from the German government and the World Health Organization.”

“The results of this trial need to be seen in the perspective of the preponderance of the existing evidence, including at least 21 controlled trials showing positive outcomes with saw palmetto preparations,” he added.

In the new trial reported in NEJM, conducted at the University of California at San Francisco, 225 men (112 in saw palmetto group; 113 placebo) 49 years of age or older with moderate to severe BPH were randomly assigned to groups who took a leading saw palmetto extract (160mg twice daily, the normal dose shown effective in over 21 clinical trials) or a matching placebo capsule. The patients made 8 study visits over a one-year period to assess changes in the AUASI scores (this is the primary outcome of the trial), maximal urine flow, post-void residual urine volume, prostate size, and other health-related outcomes. On average, participants in both the saw palmetto and the placebo groups improved over the one-year duration of the trial, but there were no significant differences in the rates of improvement overall between the two groups as measured by the AUASI.

While ABC believes that this trial employed a good design and used a high quality saw palmetto extract, the group pointed to an anomaly of the trial — the significantly higher adverse effect profile in the placebo group. Saw palmetto preparations are known to be safe and very well tolerated, producing few adverse effects. In this trial, minor adverse effects in the saw palmetto and placebo groups were nearly equal (saw palmetto, 39; placebo, 34) — evidence of the safety of saw palmetto. However, there were almost twice as many serious adverse effects in the placebo group (11) as in the saw palmetto group (6), suggesting that the patient population may have had other serious illnesses, possibly interfering in the attempt to treat the moderate-to-severe BPH symptoms.