Saw palmetto, also called shrub palmetto, is a small palm native to southern California and the southeastern United States. Several Native American tribes used the berries of this plant to treat respiratory disorders. Today, saw palmetto extract is a popular herbal medicine to address symptoms of benign prostatic hypertrophy, or enlarged prostate. Consult your doctor before using this therapy, because saw palmetto may affect blood your pressure, especially if you take other medicines.
Chemistry
The berries of Serenoa repens contain high levels of free fatty acids and plant steroids, including beta-sitosterol. The fatty oil components are most concentrated in ethanolic and hexane-derived extracts, while the water-soluble polysaccharides are more prominent in aqueous extracts of the herb.
Physical Effects
According to Drugs.com, animal studies show that saw palmetto compounds decrease the activity of 5-alpha reductase, an enzyme responsible for the conversion of testosterone to dihydrotestosterone in the prostate. The “Physicians’ Desk Reference for Herbal Medicines” says that the lipophilic extract of the herb – the form that contains fatty acids – reduces prostate enlargement by blocking dihydrotestosterone from binding to androgen receptors. The polysaccharides in hexane extracts of saw palmetto prevent the synthesis of inflammatory chemicals by blocking the conversion of cyclooxygenase and 5-lipoxygenase from arachidonic acids, the “bad” fats more commonly known as “trans” and “saturated” fats obtained from consuming animal products. This activity has led to the theory that saw palmetto might lower blood pressure as well as reduce inflammation, although there is no evidence to support this.
Side Effects
According to the Mayo Clinic, there are a small number of reports that saw palmetto preparations have caused dizziness, irregular heart rhythm and high blood pressure in people. However, it is not clear if these symptoms were produced by the herb itself or something else. In any case, check with your doctor about the potential side effects of this herb if you have a respiratory disorder, a history of high blood pressure or heart disease.
Herb-Drug Interactions
A Natural Standard review provided by Aetna InteliHealth warns that you should avoid this herb if you take medications to control your blood pressure. Because this herb may increase the effects of anti-coagulant drugs, there is an increased risk of uncontrolled bleeding from combining saw palmetto with warfarin, clopidogrel or heparin or pain relievers such as ibuprofen, naproxen and aspirin. This herb may also increase the effects of anti-inflammatory medicines and reduce the effectiveness of immune-system suppressants. Saw palmetto may produce estrogenic effects, which means it should not be used during pregnancy or lactation, if you use oral contraceptives or if you have a history of a hormone-related cancer.
References
- “Physicians’ Desk Reference for Herbal Medicines”; Thomas Brendler, et al.; 2007
- Drugs.com: Saw Palmetto
- Mayo Clinic: Saw Palmetto
- InteliHealth: Saw Palmetto
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