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.
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 suggest possible anti-tumor activity and potential for use in the treatment of cancer. These results have not been substantiated with human trials.
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 2001 study published in JAMA (The Journal of the American Medical Association) reported on a double-blind study 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.”
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.
- Tacklind, J; MacDonald, R; Rutks, I; Wilt, TJ (2009). "Serenoa repens for benign prostatic hyperplasia". In Tacklind, James. Cochrane database of systematic reviews (Online) (2): CD001423. doi:10.1002/14651858.CD001423.pub2. PMC 3090655. PMID 19370565.
- "Saw palmetto (Serenoa repens [Bartram] Small)]". Mayo Clinic. Retrieved 2011-12-15.
- Felter's complete text
- King's American Dispensatory 1898
- Markowitz JS, Donovan JL, Devane CL, et al. (December 2003). "Multiple doses of saw palmetto (Serenoa repens) did not alter cytochrome P450 2D6 and 3A4 activity in normal volunteers". Clin. Pharmacol. Ther. 74 (6): 536–42. doi:10.1016/j.clpt.2003.08.010. PMID 14663456.
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- Allison Aubrey (9 February 2006). Morning Edition: Study Casts Doubt on Saw Palmetto as Prostate Remedy (Audio recording). National Public Radio.
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- Anderson ML (2005). "A preliminary investigation of the enzymatic inhibition of 5alpha-reduction and growth of prostatic carcinoma cell line LNCap-FGC by natural astaxanthin and Saw Palmetto lipid extract in vitro". Journal of Herbal Pharmacotherapy 5 (1): 17–26. doi:10.1300/J157v05n01_03. PMID 16093232.
- "Saw Palmetto". MedlinePlus (National Library of Medicine). 2008-02-01. Retrieved 2009-03-16.
- "Effect of Increasing Doses of Saw Palmetto Extract on Lower Urinary Tract Symptoms". Journal of the American Medical Association. Retrieved 2011-10-08.
- "Saw palmetto extract likely won't relieve enlarged prostate symptoms". Los Angeles Times. 27 September 2011. Retrieved 2011-10-08.
- Assmann G, Cullen P, Erbey J, Ramey DR, Kannenberg F, Schulte H (January 2006). "Plasma sitosterol elevations are associated with increased incidence of coronary events in men: results of a nested case-control analysis of the Prospective Cardiovascular Münster (PROCAM) study". Nutrition, Metabolism, and Cardiovascular Diseases : NMCD 16 (1): 13–21. doi:10.1016/j.numecd.2005.04.001. PMID 16399487.
- Guide to Supplements-Saw Palmetto-Berkeley Wellness Letter
- Saw Palmetto for Prostate Disorders-American Academy of Family Physicians
- Complementary and Alternative Therapies For Cancer Patients Saw Palmetto-University of California at San Diego Medical Center
- Medline Suppletments-Saw Palmetto from National Institutes of Health