A new study has found that men with enlarged prostates who took higher doses of herbal supplement saw palmetto had no relief from urinary problems than those given a placebo.
Prostate enlargement, also called benign prostatic hyperplasia (BPH), can cause frequent urination, a weak or intermittent urine stream and an inability to empty the bladder completely.
The current study confirmed results of an earlier trial, which found that a standard daily dose of 320 mg provided no greater symptom relief than placebo.
“Investigators designed the current trial to determine whether daily doses of up to 960 milligrams – three times the standard daily dose — would prove better than a placebo at improving lower urinary tract symptoms in men due to BPH,” said Robert A. Star, M.D., director of the NIDDK’s Division of Kidney, Urologic and Hematologic Diseases.
“We were disappointed to find that higher doses of saw palmetto did not improve symptoms more than placebo,” he added.
Between June 2008 and October 2010, the researchers conducted a double-blind, placebo-controlled, randomized trial using up to three times the standard dose of the extract.
Participants included 369 men aged 45 years or older, each with a peak urinary flow rate of at least 4 ml/second, an American Urological Association Symptom Index (AUASI) score between 8 and 24, and no exclusions.
The researchers measured the differences between the AUASI score at the start of the trial and after 72 weeks of treatment.
Between baseline and 72 weeks, mean AUASI scores decreased from 14.4 to 12.2 points with saw palmetto extract and from 14.7 to 11.7 points with placebo.
The researchers observed no favorable effect of saw palmetto extract on any secondary outcomes.
Saw palmetto was not more effective than placebo in reducing urinary symptoms for any of the secondary outcomes.
The study was published Sept. 28 in the Journal of the American Medical Association.