Saw palmetto extract

Saw palmetto extract is an extract of the fruit of Serenoa repens. It is rich in fatty acids and phytosterols. It has been used in traditional, eclectic, and alternative medicine to treat a variety of conditions, most notably benign prostatic hyperplasia (BPH). Review of clinical trials, including those conducted by the National Center for Complementary and Alternative Medicine, found the extract to be no more effective than placebo for BPH.

Medicinal use
Saw palmetto is used in several forms of traditional herbal medicine. American Indians used the fruit for food and to treat a variety of urinary and reproductive system problems. The Mayans drank it as a tonic, and the Seminoles used the berries as an expectorant and antiseptic.

Crude saw palmetto extract was used by European/American medical practitioners for at least 200 years for various conditions, including asthenia (weakness), recovery from major illness, and urogenital problems. The eclectic medicine practitioner H. W. Felter wrote of it, "Saw palmetto is a nerve sedative, expectorant, and a nutritive tonic, acting kindly upon the digestive tract...Its most direct action appears to be upon the reproductive organs when undergoing waste of tissue..."

King's American Dispensatory (1898) says of the extract: "It is also an expectorant, and controls irritation of mucous tissues. It has proved useful in irritative cough, chronic bronchial coughs, whooping-cough, laryngitis, acute and chronic, acute catarrh, asthma, tubercular laryngitis, and in the cough of phthisis pulmonalis. Upon the digestive organs it acts kindly, improving the appetite, digestion, and assimilation. However, its most pronounced effects appear to be those exerted upon the urino-genital tracts of both male and female, and upon all the organs concerned in reproduction. It is said to enlarge wasted organs, as the breasts, ovaries, and testicles, while the paradoxical claim is also made that it reduces hypertrophy of the prostate. Possibly this may be explained by claiming that it tends toward the production of a normal condition, reducing parts when unhealthily enlarged, and increasing them when atrophied."

Saw palmetto extract is the most popular herbal treatment for benign prostatic hyperplasia, a common condition in older men. Early research indicated that the extract is well-tolerated and suggested "mild to moderate improvement in urinary symptoms and flow measures." Later trials of higher methodological quality indicated no difference from placebo. Questions of adequate blinding and delivery of any active ingredients remain. The latest Cochrane Database review (2009) concludes that "Serenoa repens was not more effective than placebo for treatment of urinary symptoms consistent with BPH."

A 2011 study published in JAMA (The Journal of the American Medical Association) reported on a double-blind study that eleven North American clinics conducted on 369 men. The study found that saw palmetto fruit extract failed to reduce urinary tract symptoms more than placebo. Men in the experimental group experienced a 2.20 point drop in their American Urological Assn. Symptom Index (AUASI) score. However, men in the placebo group saw a 2.99 point drop. The Los Angeles Times reports, “42.6% of the men in the extract group saw their AUASI scores fall by at least three points; 44.2% of the men in the placebo group saw the same degree of benefit.” The study was funded by several offices within the NIH, including the National Center for Complementary and Alternative Medicine.”

Inhibition of both forms of 5-alpha-reductase with no reduction in cellular capacity to secrete prostate-specific antigen is indicated. Other proposals for mechanisms of action include interfering with dihydrotestosterone binding to the androgen receptor, relaxing smooth muscle tissue similarly to alpha antagonist drugs, and acting as a phytoestrogen.

Limited in vitro and animal model studies have investigated potential for use in the treatment of cancer. However, according to the American Cancer Society, "available scientific studies do not support claims that saw palmetto can prevent or treat prostate cancer in humans".

Saw palmetto extract has been suggested as a potential treatment for male pattern baldness.

Contraindications and side effects
Few side effects or allergic reactions are associated with saw palmetto extract use. The most common are gastrointestinal, some of which may be reduced by taking the extract with food. Use may increase the risk of bleeding or affect sex hormones, and concurrent use of other drugs with similar action should be avoided.

Beta-sitosterol, a chemical present in saw palmetto extract, is chemically similar to cholesterol. High levels of sitosterol concentrations in blood have correlated with increased severity of heart disease in men who previously suffered heart attacks.

As with other herbal preparations, precise chemical constituents may vary by manufacturer and batch. Contraindications include pregnancy, lactation due to antiandrogenic and estrogenic activity.