WASHINGTON U.-ST. LOUIS (US) — Supplements made from the fruit of the saw palmetto tree do not relieve symptoms of an enlarged prostate, even when taken in very large doses.
Older men in the U.S. and Europe often take the supplement in an attempt to reduce bothersome symptoms of a swollen prostate, including frequent urination and a sense of urgency. Doctors in Europe often recommend it over more traditional drug treatments.
Results of the study published in the Journal of the American Medical Association, may settle an ongoing debate over the effectiveness of saw palmetto for the condition known as benign prostatic hyperplasia (BPH).
“Now we know that even very high doses of saw palmetto make absolutely no difference,” says Gerald Andriole, professor and chief of urologic surgery at Washington University in St. Louis. “Men should not spend their money on this herbal supplement as a way to reduce symptoms of enlarged prostate because it clearly does not work any better than a sugar pill.”
The multi-center study, led by Michael Barry at Massachusetts General Hospital, involved more than 300 men ages 45 and older who had moderate symptoms suggestive of an enlarged prostate, such as frequent urination, difficulty emptying their bladders, and a weak urine stream. The men were randomly selected to receive a daily dose of saw palmetto extract, beginning at 320 milligrams, or an identical-looking placebo pill with the same distinctive smell and taste.
After 24 weeks, the saw palmetto dosage was increased to 640 milligrams a day, and after another 24 weeks, to 960 milligrams a day—triple the standard dose. In all, men took saw palmetto or a placebo for nearly 17 months. Neither the physicians nor the patients knew who was taking what regimen until the end of the study.
The researchers found that among men who took saw palmetto, prostate problems improved slightly but not more than in men taking a placebo.
“We commonly see this in clinical trials,” Andriole explains. “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.”
Saw palmetto had no greater effect than the placebo on BPH symptoms as well as other conditions related to an enlarged prostate including waking at night to urinate, PSA level, and bladder control.
The research was funded by the National Institutes of Health, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center for Complementary and Alternative Medicine, and the NIH Office of Dietary Supplements.
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