Saw Palmetto for Benign Prostatic Hyperplasia Symptoms

From the Spring 2010 issue of Quality Care®, NAFC's newsletter

From the National Center for Complementary and Alternative Medicine (NCCAM)

More than half of men age 50 or older, and as many as 90 percent of men in their 70s and 80s, have symptoms consistent with benign prostatic hyperplasia (BPH). Lower urinary tract symptoms (LUTS) associated with BPH can range from mild to very bothersome, and include frequencey or urgency of urination, nocturia, slow stream, and leakage. Urinary retention associated with BPH potentially can lead to complications.

An increasing number of men are treating their BPH symptoms with boanical preparations sold over-the-counter, and using them as individual agents or in combination with prescribed drugs.

Saw Palmetto
Saw palmetto (Serenoa repens, made from ripe berries of the American dward palm) is the botanical that is most used for symptoms of BPH and most studied in clinical trials. In the 2007 national survey on Americans' use of complementary and alternative medicine (CAM), among respondents who used natural products as CAM, approximately 1.7 million Americans used saw palmetto.

Basic research on saw palmetto in laboratory and animal studies has revealed the following findings that may be relevant to its potential application in treating BHP:

• Saw palmetto appears to contain components that have activity similar to 5-alpha-reductase inhibitors, which prevent conversion of testosterone to dihydrotestosterone (a male hormone created from testosterone).
• Saw palmetto contains substances, including certain fatty acids that may have weak hormone aggressive effects, as well as stopping or slowing the reproduction of cells, and anti-flammatory properties.

Practice Guidelines
The American Urological Association's (AUA) evidence-based guideline on diagnosis and treatment of BPH recommends:

• For patients whose symptoms are mild or moderate, or who have severe symptoms that are not bothersome or do not interfere with daily activities of living, watchful waiting is preferred.
• For patients with bothersome moderate-to-severe symptoms, treatment options include watchful waiting and one or more of the following therapies: alpha-adrenergic blockers and 5-alpha-reductase inhibitors, separately or combined minimally invasive therapies, such as transurethral microwave heat treatments or transurethral needle ablation and, if earlier interventions have not resolved the problem, surgical treatment.

The AUA also states that phytotherapeutic agents (i.e., plant-derived medications such as saw palmetto) and other dietary supplements cannot be recommended to treat BPH. Despite widespread use, their mechanisms of action, effectiveness, and safety have not been sufficiently documented in high-quality clinical trials.

The sixth International Consultation on New Developments in Prostate Cancer and Prostate Diseases (held in 2005 and including AUA representation) focused on LUTS, including BPH, in older men. In regard to "alternative treatments," it notes that while progress has been made toward isolating components and identifying possible mechanism(s) of action, it is difficult to compare studies, and further research is needed.

Systematic Review/Meta-Analyses
Findings from systematic reviews of saw palmetto for symptoms of BPH have been mised, and the topic is an active area of debate. The number of trials available, especially randomized controlled trials (RCT), is modest. Many earlier trials--in contrast to two recent, better designed RCTs--have had issues that can affect the validity of findings, such as short duration, small size, and/or not having used standardized outcome measures.

A 2009 Cochrane review of 30 trials concluded that saw palmetto has little or no efficacy over placebo for treating BPH symptoms, although it appears to be safe.

Other systematic review/meta-analyses include:

• A 2005 review on 38 studies (mostly on one commerical product), by the Natural Standard Research Collaboration, which concluded in favor of efficacy.
• A 2002 meta-analysis on 17 published studies of a European commerical saw palmetto extract, by the European Institute of Oncology, which found suggestions of effectiveness over placebo on several measures in BPH symptoms.

Safety
Saw palmetto is likely safe when used in typical doses, but more needs to be learned about its long-term safety and effectiveness. Thus the possibility exists that there is variability with respect to the dosage, packaging, and manufacturing of this product. Saw palmetto may cause mild side effects like diarrhea. Some men who use saw palmetto have reported headache, dizziness, tender breast, or reduction in sexual desire. Since many of saw palmetto's purported active constituents are fat soluble, product forms that use water extraction (such as teas) might be less effective. For more on the botanical, click here.

About the author:

The National Center for Complementary and Alternative Medicine (NCCAM) is the federal government's lead agency for scientific research on complementary and alternative medicine (CAM). NCCAM sponsors and conducts research using scientific methods and advanced technologies to study CAM.

The mission of NCCAM is to explore complementary and alternative healing practices in the context of rigorous science, train compementary and alternative medicine researchers, and disseminate authoritative information to the public and professionals.