Saw Palmetto & Estrogen

Saw palmetto contains chemicals that influence estrogen levels.
Image Credit: KathyKafka/iStock/Getty Images

Saw palmetto is a palm-like plant indigenous to the southeastern United States from South Carolina to Florida. Also known as shrub palmetto, this small, bushy tree produces purplish-black berries that are used in herbal medicine to treat enlarged prostate in men triggered by low testosterone. Saw palmetto is of significance to both men and women because it has an effect on estrogen. Because of these hormonal effects, seek the advice of qualified health care practitioner before using this herb.

Active Compounds

The chief active compounds in saw palmetto berries are flavonoids and steroids, including several derivatives of beta-sitosterol and other plant sterols. Saw palmetto also contains fatty acids and water-soluble polysaccharides, or carbohydrates like glycogen and starch.


Effect on Estrogen Receptors

Beta-sitosterol is a natural alpha-adrenergic receptor blocker. Specifically, it prevents a degraded form of testosterone called dihydrotestosterone from accumulating in prostate tissue that would otherwise cause excessive cell growth and inflammation. The plant steroids in saw palmetto also act on progesterone receptors, an action that causes a reduction in estrogen levels. According to the results of a large international trial published in the "Journal of Clinical Oncology" in April 2011, estrogen and progesterone receptor status is a predictive marker of early breast cancer and post-treatment relapse.


Other Anti-Estrogen Actions

As hormone levels decline with age, the number of fat cells in your body increases. This promotes higher levels of an agent called aromatase, an enzyme that converts testosterone to estrogen. The treatment of benign prostatic hyperplasia in men and breast cancer in post-menopausal women is addressed with a class of drugs called aromatase inhibitors. According to Jaroslav Drsata, a scientist in the Czech Republic, the enzyme-blocking properties of saw palmetto may include aromatase.

Safety Considerations

Because of the estrogenic properties of saw palmetto, you should not use this herb during pregnancy, while nursing or if you have a history of a hormone-related cancer or are undergoing hormone replacement therapy. Saw palmetto may interact with other medicines, including anti-inflammatory drugs, blood pressure medications, birth control pills and antibiotics. Talk to your doctor before using this herb if you have any of these conditions or take other medications.