NEJM: Saw Palmetto No Benefit to BPH, ABC Clarifies Study Parameters

SAN FRANCISCO--A study funded by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Center for Complementary and Alternative Medicine (NCCAM) found saw palmetto (Serenoa repens) had no more effect than placebo in men with moderate to severe symptoms of benign prostatic hyperplasia (BPH). Reported in the Feb. 9 issue of the New England Journal of Medicine (354, 6:557-66, 2006), the trial also reported while mild adverse effects were relatively equivalent between the saw palmetto and placebo groups, there were significantly more serious adverse effects reported by those taking placebo. The herbal and nutritional products industry challenged application of these results, based on study parameters and the wealth of past positive results on the efficacy and safety of saw palmetto and BPH.

In the NEJM study, researchers from the University of California, San Francisco, randomly assigned 225 men aged 49 or older with moderate to severe BPH into two treatment groups--112 men took either 160 mg twice daily of a leading saw palmetto extract, while 113 men took placebo doses. Over the course of a one-year-period, patients made eight study visits, during which researchers assessed changes in AUASI (American Urological Association symptom index) scores, maximal urine flow, post-void residual urine volume, prostate size and other health-related outcomes. On average, improvements were recorded for patients in both study groups, as measured by AUASI, but there were no significant differences between the two groups relative to improvement in BPH symptoms.

Mark Blumenthal, founder and executive director of the American Botanical Council (ABC), explained saw palmetto is widely recognized for its safety and efficacy in treating mild to moderate symptoms associated with BPH, a non-cancerous swelling of the prostate gland in older men that can result 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, he said, noting the men in this latest study had advanced to severe BPH, in contrast to most of the previous controlled trials showing positive results and efficacy for saw palmetto in men with mild to moderate symptoms. 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 (WHO). Thus, he advised the results of this trial 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.

Both Blumenthal and Andrew Shao, Ph.D., vice president of the Council for Responsible Nutrition (CRN), agreed the NEJM study was well-designed and used a high quality saw palmetto extract at the dosage shown effective in 21 controlled trials. Shao said exclusion of patients with mild BPH might have reduced the ability to detect the benefits of the herb, while Blumenthal suggested a third arm involving higher dosages could have tested dose-response at another level. That there were almost twice as many serious adverse effects in the placebo group compared to the saw palmetto group in the NEJM trial, Blumenthal added, suggests the patient population may have had other serious illnesses, possibly interfering in the attempt to treat the moderate-to-severe BPH symptoms.

In further defense of saw palmetto, Blumenthal cited a Cochrane Database review that revealed 21 clinical trials involving more than 30,000 men with mild to moderate BPH concluded saw palmetto was safe and effective compared to either placebo and drug (finasteride aka Proscar<\#168>) treatment, with fewer side effects than the drug. Based on this wealth of positive research, saw palmetto has been approved as a safe and effective BPH treatment by the German governments respected Commission E as well as by the Canadian governments Natural Health Products Directorate. The herbal remedy has also been accepted in Western Europe by way of a monograph by the European Scientific Cooperative on Phytotherapy (ESCOP), which acknowledges its efficacy for symptomatic treatment of micturition (urinary) disorders in mild to moderate BPH. Likewise, WHO acknowledges the efficacy of saw palmetto for treating lower urinary tract symptoms secondary to stage 1 and 2 BPH.

It is estimated that more than 2.5 million U.S. men use saw palmetto preparations, driving total U.S. retail sales of the saw palmetto supplements to as much $130 million, placing it among the top 10 most popular herbal supplements.