"Many different preparations (of saw palmetto) have been looked at without convincing evidence that one is better than another," said Dr. Timothy Wilt, senior author of the study and a researcher at the Minneapolis Veterans Affairs Medical Center. "I believe we should move on and look elsewhere" for effective treatments.

More than 1.6 million U.S. adults said they had used saw palmetto in the past 30 days in a 2007 survey by the Centers for Disease Control and Prevention.

Early studies on saw palmetto concluded that the plant could ease the symptoms of benign prostatic hyperplasia (BPH), or enlarged prostate, which include difficulty urinating, urine leakage and the need to go to the bathroom several times during the night.

More recent studies done with more reliable methods, however, found that the plant extract was no better at alleviating symptoms than taking a placebo pill.

To weigh what all the existing research has to say on saw palmetto, Wilt and his colleagues collected the results from 17 studies that compared saw palmetto to placebo.

The trials lasted anywhere from four to 72 weeks, and most used a standard daily saw palmetto dose of 320 mg. The average age of participants was 64.

When the researchers focused on studies that lasted longer than six months, they found that men who took the plant extract generally had fewer symptoms and sometimes better urinary flow, but that these improvements were no greater than those seen among the men who took the placebo.

"Two new studies (included in the analysis) were very high quality studies, and they provided the best information that I think strongly indicates that these preparations, as used in these studies, are not effective," Wilt told Reuters Health.

Dr. Michael Barry at Massachusetts General Hospital led one of those recent trials. It looked at whether higher doses of saw palmetto might offer greater improvements (see Reuters Health report of September 27, 2011).

"We decided, with careful monitoring, to go up to twice and three times the standard dose to see if we could find a better effect than placebo, and we couldn't," Barry said.

Barry, who did not participate in Wilt's analysis, pointed out there were still some benefits seen from saw palmetto.

For instance, Barry's group found that 40 percent of men experienced a four-point reduction in symptoms on a 35-point scale. "That's a level that men would say they feel better," Barry said.

"It's not that there's no response, but that it's about the same as placebo, and we know the placebo response is pretty high," he told Reuters Health.

Prescription medications used to treat enlarged prostate symptoms include so-called Alpha-1 blockers such as doxazosin (Cardura), prazosin (Minipress), tamsulosin (Flomax) and terazosin (Hytrin). Hormonal treatments include finasteride (Propecia, Proscar) and dutasteride (Avodart).

Barry said some men might still want to try saw palmetto, even if all they're getting is a placebo effect, where just the expectation of feeling better yields some improvement.

On the other hand, he said, there's a cost. Saw palmetto extract sells for about $11 for 90, 320-mg pills.

Wilt said there are other, free actions men can take that can help relieve symptoms, and "avoid the unnecessary costs of a product that is not effective."

These include limiting fluids before bed, avoiding alcohol and caffeine and taking prescription medications if behavioral changes don't work.

SOURCE: bit.ly/LdpAe7 BJU International, online May 2, 2012.

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