Lack of proper controls and other issues raises concerns about findings regarding widely used supplement
WASHINGTON, DC (February 9, 2006) - A study published in today’s edition of New England Journal of Medicine (NEJM) suggesting that the popular male herbal supplement saw palmetto marketed to ease problems associated with an enlarged prostate, is ineffective, has a number of flaws according to one of the dietary supplement industry’s leading trade associations, the National Nutritional Foods Association (NNFA). Specifically, NNFA cited a substantial existing body of clinical studies, some with larger patient populations, that support the efficacy of this supplement for mild to moderate symptoms associated with benign prostatic hyperplasia (BPH).
“We need to remember that this is just one study – there are currently more than 20 clinical trials on saw palmetto, that have randomized over 3,000 subjects with durations of four to 48 weeks, most of which clearly support saw palmetto’s efficacy for mild to moderate symptoms of BPH, not moderate to severe as was indicated in this study,” said Daniel Fabricant, NNFA’s vice president of science and quality assurance. “In addition, despite the study authors’ own enthusiasm about their study design, there are areas that were not addressed that make their conclusions questionable.”
One major issue to which NNFA took exception was the lack of a positive control, such as a conventional pharmaceutical intervention, in the study design. “If CAM [complementary and alternative medicine] therapies are going to be evaluated with the accepted scientific yard stick, then the accepted tool must be used, which is a randomized, placebo- and positive-controlled clinical trial,” said Fabricant.
Fabricant also said the authors failed to provide effective chemical and biological standardization of the test materials. For instance, the authors did not investigate the saw palmetto test material in comparison with other formulations used in previous trials nor did they provide confirmation by in vitro bioassay or other appropriate means that the placebo was biologically inactive. NNFA also faulted the study’s measurement of only one hormonal marker associated with BPH.
“The scientific explanations behind BPH are diverse and evolving,” Fabricant said. “For instance, research indicates that estrogen may lead to abnormal cell proliferation in the prostate. Also, genetic variations in steroid receptor expression in individuals; as well as the ratios of other hormones such as DHT, to estrogens are factors that may all play a role in the occurrence of BPH. The authors only provide testosterone as a sole hormonal marker related to BPH, which, in light of current research on BPH, does not present an adequate scientific window to view the whole scene.”
The NEJM study was conducted over the period of a year on 225 male patients over the age of 49 with moderate to severe symptoms of BPH, such as frequent and difficult urination. Patients were given either placebo or 160 milligrams of saw palmetto. The study concluded, based on self-reports from patients and a blood test to determine changes in a chemical marker for prostate cancer risk, that saw palmetto showed no effect in easing urinary symptoms and did not decrease prostate size.
Daniel Fabricant is the new vice president of scientific affairs for NNFA. An expert in dietary supplements for women’s health, sports nutrition, and quality analysis of botanical products, Fabricant comes to NNFA with more than a decade of research and practical experience with natural products.
NNFA ( www.nnfa.org ) is the nation's largest and oldest non-profit organization dedicated to the natural products industry. NNFA represents more than 8,000 retailers, manufacturers, wholesalers and distributors of natural products including foods, dietary supplements, and health and beauty aids. In addition to offices in Washington D.C. and Newport Beach , Calif. , NNFA also has seven regional offices throughout the United States and is governed by a 22-member board of directors representing all segments of industry.