The leaves and berries of a Serenoa repens tree. The extract taken from these berries, known as saw palmetto, has long been held to relieve symptoms for men with enlarged prostrates. However, a new study suggests there is no benefit.
Credit: Wikimedia commons
WASHINGTON: A widely sold herbal supplement thought to relieve symptoms in men with enlarged prostates carries no real benefit over a placebo, new research has found.
The global market for saw palmetto (Serenoa repens) is roughly $700 million a year, and supplements containing the herb are widely available throughout North America, Europe and Australia.
However, a randomised trial at 11 sites in North America showed that even triple doses of over-the-counter drugs containing the extract neither worked nor harmed the patients. The findings were described this week in the latest edition of the Journal of the American Medical Association.
"Astonishingly enough, there was not any measurable effect - either in benefits or in toxicity - with increasing doses of the supplement in comparison to placebo," said urologist and co-author Claus Roehrborn from the University of Texas Southwestern in the U.S.
"These supplements are apparently not doing anything measurably above and beyond what we call the placebo effect," he added.
Increased dosage, still no benefit
Led by Michael Barry of Massachusetts General Hospital in Boston, researchers followed 379 men age 45 and older whose symptoms included difficulty emptying their bladders, weak and/or frequent urination.
As part of the randomised trial, some received saw palmetto extract - which comes from the berries of the saw palmetto dwarf plant tree, which is endemic to the east coast of the U.S. - and others were given a sugar pill that smelled and tasted the same.
Measurements showed the drug, even when increased in dosage over 72 weeks, had no impact on urinary symptoms such as nighttime urination or incontinence, and did not improve sexual function or allow men to sleep better - additional benefits the extract is marketed as having.
"None of them showed any effect whatsoever in contrast to placebo," said Roehrborn. "These supplements cost about $30 or more a month, and they obviously don't help."
Prostate trouble common with age
Enlarged prostate is a common condition of aging that affects about half of men in the United States over age 50, and 75% by age 80.
The growth of the prostate can make it difficult to urinate and can cause urinary tract infections.
Medication and surgery are some of the treatment options, though herbal supplements with anti-inflammatory properties have also been widely used for decades in the belief that they can ease symptoms.
The experiment was carried out in response to earlier indications that the standard dose was having no medical benefit - so researchers tripled the dosage to further test its benefits.
Placebo group experience same improvements
The men in the study did tend to experience a slight improvement in symptoms, but the trend was observed in both groups.
"We commonly see this in clinical trials," said co-author Gerald Andriole, chief of urologic surgery at Washington University School of Medicine in St. Louis.
"Patients often report an improvement in symptoms because they are taking something, even if it is a placebo. But in this study, there was no benefit to taking saw palmetto over the placebo."
The research was conducted under an investigational new drug application from the Food and Drug Administration, and was funded by the National Institutes of Health and the National Center for Complementary and Alternative Medicine.
The saw palmetto pills and placebos were donated for the study by Rottapharm/Madaus - an international pharmaceutical company based in Germany.
