Saw palmetto is a small, slow-growing palm native to southeastern United States. The fruits are a rich source of fatty acids and phytosterols and have been used to promote urination, reduce inflammation, and for treatment of prostatic conditions such as benign prostatic hyperplasia (BPH).
Saw palmetto has been studied in many controlled clinical trials. Whereas data from some studies indicate that it improves lower urinary tract symptoms in patients with benign prostatic hyperplasia (2) (3) (4) (5) (15) (17) (18) (26), conflicting data suggest no such effects (6) (14) (19) (28).
In another study, a saw palmetto extract did not affect the serum prostate specific antigen more than placebo, even at high doses (30).
But saw palmetto may benefit patients with chronic bacterial prostatitis when coadministered with Urtica dioica, curcumin and quercitin (16); and along with selenium and lycopene exerts anti-inflammatory effects (31). Pretreatment with saw palmetto reduced intra- and postoperative complications in patients who underwent transurethral resection of the prostate and open prostatectomy (22). However, saw palmetto use was not associated with risk of prostate cancer (27).
A saw palmetto extract was found to inhibit growth of normal prostate cells and increase their sensitivity to radiation in vitro, but did not affect malignant prostate cancer cells (20). Due to the increased risk of normal tissue complications, patients should consult with a physician before using saw palmetto supplements during radiation therapy. There is an ongoing study to determine the effects of saw palmetto on symptom management during radiation therapy (32).
In a recent study, of the 37 saw palmetto-containing supplements tested using DNA barcoding, 6% contained related species that cannot be legally sold as herbal dietary supplements in the U.S. The identity of 9% supplements remains inconclusive (33).