Prostate problems top the list of many older men's health concerns. One herbal remedy, saw palmetto, seems to promise relief from some of the urinary problems that come with an enlarged prostate, but exactly how it works is unclear. A study in a recent issue of Urology adds to what scientists know about what effect -- if any -- saw palmetto has on men's urinary tract health.

Testing an herbal remedy

University of Chicago researchers recruited 85 middle-aged and older men with lower urinary tract symptoms (urinary frequency, difficulty in urinating or in fully emptying the bladder). Half the group received 320 mg saw palmetto daily for 6 months; the other group received placebo (inactive sugar pills). Urinary tract symptoms, sexual function, and urinary flow were measured in all participants at the start of the study and at 2-month intervals.

The men who received saw palmetto saw significant improvements in lower urinary tract symptoms when compared with the placebo group. Urine flow rate improved slightly in both groups, suggesting a "placebo effect," and there was no difference between the groups in measurements of sexual function.

How does it work?

While it does seem to be of some benefit to men with enlarged prostates, just why it is helpful is by no means clear. An enlarged prostate can cause urination problems by pushing up against the urethra, the duct leading from the bladder, partially obstructing urine flow. Some studies suggest that saw palmetto helps to ease urine flow by reducing the prostate's pressure against the urethra. Other studies have been less conclusive, so there are still some major information gaps in what we know about how it affects the prostate. Regardless, saw palmetto is a widely used herbal remedy, both by itself and in combination with standard medications.

Read the fine print

A scientist who reviewed this study cautions that it's important to distinguish between what the herb might be able to do -- improve moderate lower urinary tract symptoms in men with benign prostatic hyperplasia (non-cancerous enlarged prostate) -- and what it can't do. Saw palmetto will not affect prostate specific antigen (PSA) levels. It will not cure or arrest the progression of prostate cancer or eliminate the need for surgery.

Given those limitations, saw palmetto seems to be safe to use at standard doses, but it -- and all over-the-counter herbs -- should be considered a medication. As such, men who want to give it a try should inform their physicians, so it can be noted in their medical records along with other current medications.