Saw Palmetto, Serenoa repens, is the sole species currently classified in the genus Serenoa. It has been known by a number of synonyms, including Sabal serrulatum, under which name it still often appears in alternative medicine. It is a small palm, normally reaching a height of around 2-4 m. Its trunk is sprawling, and it grows in clumps or dense thickets in sandy coastal lands or as undergrowth in pine woods or hardwood hammocks. Erect stems or trunks are rarely produced but are found in some populations. It is endemic to the southeastern United States, most commonly along the Atlantic and Gulf coastal plains, but also as far inland as southern Arkansas.

Saw palmetto is a fan palm (Arecaceae tribe Corypheae), with the leaves with a bare petiole terminating in a rounded fan of about 20 leaflets. The petiole is armed with fine, sharp teeth or spines that give the species its common name. The leaves are 1-2 m in length, the leaflets 50-100 cm long. They are similar to the leaves of the palmettos of genus Sabal. The flowers are yellowish-white, about 5 mm across, produced in dense compound panicles up to 60 cm long. The fruit is a large reddish-black drupe and is an important food source for wildlife.

The genus name honors American botanist Sereno Watson.

Uses

Native Americans used the fruit for food, but also in the treatment of a variety of urinary and genital problems. The European colonists learned of the use of saw palmetto. It was used as a crude extract for at least 200 years for various conditions including asthenia (weakness), recovery from major illness, and urogenital problems. For instance, the Eclectic physician 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 reprodutive organs when undergoing waste of tissue..."

In modern times, much research has been done on extract made from the fruits which are highly enriched with fatty acids and phytosterols. This research has been the subject of a thorough meta-analysis published in the medical journal JAMA and has been shown effective for the treatment of men with symptomatic benign prostatic hyperplasia (enlargement of the prostate) compared to placebo and the two major categories of drugs used for men with this condition. There are also small, positive clinical trials published on the use of saw palmetto extracts topically and internally for male-pattern baldness. In 2005, a long-term, placebo-controlled trial showed that a combination of saw palmetto fruit and nettle root extracts were effective in treating urinary tract symptoms in older men. However, in February 2006, a large, blinded placebo-controlled study published in the New England Journal of Medicine showed no reduction of symptoms from enlarged prostate by taking saw palmetto, as compared to placebo. Designers of the latest study questioned whether the differently-flavored placebos in previous studies were adequately blinded. Critics of the latest study questioned whether a sufficient dosage of active ingredients was given. An earlier single case study on saw palmetto concluded that searching for information on a herbal medicine using MEDLINE alone was insufficient, and expanded their search to "alternative" databases, including AGRICOLA, EMBASE, IBIS, and Cochrane, plus a manual search of unindexed herbal journals.

Other research has shown that the herb works by multiple mechanisms, including inhibiting 5-alpha-reductase, interfering with dihydrotestosterone binding to the androgen receptor, by relaxing smooth muscle tissue similarly to alpha antagonist drugs, and possibly by acting as a phytoestrogen.

Because the fruit is the part used and because a prolific quantity is produced by an adult saw palmetto tree, this herbal medicine is considered ecologically sustainable.

Though in vitro studies suggest saw palmetto has properties that might make it useful against prostate cancer cells or to reduce prostatitis, clinical trials are lacking.

Contraindications and side effects

Though men taking saw palmetto may develop mild nausea, reduced libido, or erectile dysfunction, the rate of such problems is clinically and statistically far less common than in men taking drugs to treat BPH symptoms, based on the JAMA meta-analysis cited above. There are no known drug interactions. It should generally be avoided in pregnancy and lactation and in small children due to lack of experience and knowledge in these populations and because of the purely theoretical risk of hormonal interference.

While saw palmetto is generally considered safe, one of its primary active ingredients, beta-sitosterol, is chemically similar to cholesterol. High levels of sitosterol concentrations in blood have been correlated with increased severity of heart disease in men who have previously suffered from heart attacks.

It has also been used as a herbal treatment for baldness.

References and external links

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1. Felter's complete text.
8. "Study Casts Doubt on Saw Palmetto as Prostate Remedy" by Allison Aubrey. (Audio recording.) Morning Edition. National Public Radio, 9 Feb 2006.

• Serenoa in Flora of North America
• Serenoa repens
• Serenoa repens from Floridata
• 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

Palms | Dietary supplements | Medicinal herbs and fungi

Sägepalme | Serenoa repens