Saw palmetto is a fruit extract that some men take for the symptoms of an enlarged prostate - like difficulty urinating, urine leakage or having to get up repeatedly at night for a trip to the bathroom.

The supplement is popular, despite a lack of evidence that it works. Two recent clinical trials found that saw palmetto was no more effective than sugar pills for men with an enlarged prostate, also known as benign prostate hyperplasia (BPH).

Still, with the supplement readily available over the counter, many men are likely to keep using it, according to Dr. Andrew L. Avins, a research scientist at Northern California Kaiser Permanente in Oakland.

"Since it's a dietary supplement, it can still be sold without evidence of efficacy," Avins noted in an interview. "And from past studies, we know that even without evidence, many people continue to take supplements based on what they believe."

So it's important to see whether there's a risk of any serious side effects, Avins said.

For their study, he and his colleagues looked at data from one of the clinical trials that tested saw palmetto for BPH.

The original study was a U.S. government-sponsored trial where 369 men with BPH were randomly assigned to take saw palmetto capsules or a placebo for 18 months.

Researchers found that urinary symptoms tended to improve, on average - but the benefit was no greater with saw palmetto than with the placebo.

On the positive side, Avins's team found that the risk of side effects seemed no bigger with the supplement either.

The most common complaints included upset stomach, muscle soreness and respiratory infections, and men in the supplement and placebo groups had the same number of complaints -- about three, on average.

And in the end, only a handful of those symptoms were considered to be related to the study itself, Avins's team reports in the Journal of Urology.

Still, that doesn't necessarily mean the supplement is risk-free, Avins cautioned.

"We can only talk about the use of saw palmetto at these doses, over 18 months," he said. (Men in the trial took anywhere from 320 to 960 milligrams of saw palmetto per day.)

"We can't address what happens when men take it for years," Avins said.

There's also little known about whether saw palmetto might interact with any medications a man might be taking.

Then, of course, there's the other question of whether there's any benefit to gain from using saw palmetto.

"On average," Avins said, "it doesn't appear any better than a placebo."

But, he added, if a man actually feels better from using saw palmetto - even via the "placebo effect" - he might think it's a worthwhile investment (at around $11 for 90 320-mg pills).

Avins stressed, however, that men should talk to their doctors about using any supplements. One reason is to help avoid any potential interactions with the prescription drugs they may be taking.

But another reason is to make sure you know about all the options for treating symptoms of an enlarged prostate.

"This is a condition where good conventional options do exist," Avins said.

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

For some men, surgery may be recommended.

There are also some simple, no-cost steps men can take. Limiting fluids before bed, and cutting out caffeine and alcohol, can be helpful.

SOURCE: bit.ly/Vk83Ir Journal of Urology, online October 10, 2012.

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