A six-month-long carefully controlled study by physicians at the University of Chicago, published in the December issue of the journal Urology, shows that the herbal remedy saw palmetto can improve symptoms for men with lower urinary tract problems, but that it has no significant impact on urinary flow rates, quality of life, or sexual function. Although several smaller, briefer and uncontrolled trials of saw palmetto (serona repens) have implied benefits from this herb, many physicians have remained skeptical.
Men with urinary symptoms - such as an enlarged prostate, which can interfere with their efforts to empty their bladders - have not shared these doubts. They spend more than $140 million a year on herbal preparations containing saw palmetto, making it one of the 10 best-selling herbal remedies.
"Our study provides the best evidence to date that saw palmetto can have a beneficial effect," said Glenn Gerber, M.D., associate professor of surgery at the University of Chicago and director of the study.
Gerber and colleagues at the University of Chicago and at the Dekalb Clinic, in Dekalb, Illinois, enrolled 94 men who complained of urinary retention in the trial. During the first month of the study all participants received a placebo capsule twice a day. After the first month, nine men who reported considerable improvement were removed from the trial.
The remaining 85 men were randomly selected to receive two capsules a day of either saw palmetto or a placebo.
After the one-month placebo "run-in period,' the study subjects filled out a standardized questionnaire about their urinary symptoms, a second questionnaire about sexual function, and a third questionnaire about quality of life. They also had their urinary flow rates measured. The tests were repeated two, four and six months into the trial.
After six months on the mediction, the men who received saw palmetto had a 4.4-point decrease (improvement) in their urinary symptom score, from an average of 16.7 down to 12.3. Men who received only the placebo also had a reduction but of only half the size, 2.2 points, from 15.8 down to 13.6.
There were no significant differences between the two groups in the other measurements. Peak urinary flow rates improved slightly in both groups. Self-assessed quality of life improved slightly in both groups. There was no change in sexual function.
This may not provide the final word on saw palmetto, which has not yet been compared with standard medications for an enlarged prostate, but it does "tell doctors how to talk to patients about this supplement," said Gerber. "Saw palmetto clearly offers symptomatic benefit as compared with placebo controls."
"We can tell patients that this appears to be a safe, well-tolerated substance that can produce short-term improvement of urinary symptoms," said Gerber. "But we also need to point out that we don't know why it works, and that the dose can vary widely and unpredictably in over-the-counter preparations, which may also include other untested herbal supplements."
