A recent clinical trial, published in the September 28, 2011 issue of JAMA, shows that saw palmetto does not reduce urinary problems associated with prostate enlargement.
Saw palmetto is widely used as an herbal dietary supplement. Saw palmetto has often been used for treating lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). However, recently the effectiveness of saw palmetto in treating BPH has been questioned, at least at standard doses (320 mg/d). In this new study, saw palmetto was no more effective than placebo. It provided no greater symptom relief than placebo.
BPH is a non-cancerous enlargement of the prostate, the walnut-sized gland located at the base of the urinary bladder in men. More than half of men in their 60s, and up to 90% in their 70s and 80s, have symptoms of BPH. BPH can cause frequent urination, a weak or intermittent urine stream, and an inability to empty the bladder completely.
According to Robert A. Star, M.D. of the NIDDK‘s Division of Kidney, Urologic and Hematologic Diseases, “Investigators designed the current trial to determine whether daily doses of up to 960 milligrams would prove better than a placebo at improving lower urinary tract symptoms in men due to BPH.”
“This was a well-designed study that addressed limitations of earlier, smaller trials — it was a multicenter study with a larger sample size and tested different doses of a carefully analyzed saw palmetto product,” said Josephine P. Briggs, M.D., director of the National Center for Complementary and Alternative Medicine (NCCAM).
A total of 369 men aged 45 years or older participated in the study. Each participant had a peak urine flow rate of at least 4 milliliters per second at the beginning of the study — which is less than normal. Also, all had an American Urological Association Symptom Index (AUASI) score between 8 and 24 — the lower the score, the fewer the symptoms. Escalating doses of saw palmetto or placebo were given.
The study measured the differences between the AUASI score at the start of the trial and after 72 weeks of treatment. The average AUASI score decreased from 14.4 to 12.2 points with saw palmetto and from 14.7 to 11.7 points with placebo. The average change in AUASI score between the saw palmetto and placebo groups was 0.79 points, favoring placebo. Thus, saw palmetto was not any more effective than placebo in reducing urinary symptoms. The symptoms that were measured included: improvements in frequency, nocturia (nighttime urination), peak urine flow, prostate-specific antigen (PSA) level, sexual function, incontinence, and sleep quality.
“We were disappointed to find that higher doses of saw palmetto did not improve symptoms more than placebo,” said Dr. Star.