Saw palmetto takes a hit in long-term BPH study

The popular herbal therapy saw palmetto appears to be no more effective than placebo for relieving symptoms of BPH, according to a year-long, double-blind study published last week in the New England Journal of Medicine (2006; 354:557-66).

Researchers randomly assigned 225 patients over the age of 49 years with moderate-to-severe symptoms of BPH to 1 year of treatment with saw palmetto or placebo twice a day. Subjects returned at regular intervals to be assessed for symptoms and side effects.

“If you look at the change in symptoms over time between the two groups, it was almost identical,” said lead author Stephen Bent, MD, of the San Francisco Veterans Affairs Medical Center and the University of California, San Francisco. “There was no statically significant difference at any time point during the study. The results of this study clearly do not support a strong clinical benefit of saw palmetto for BPH.”

Dr. Bent acknowledged that the results are surprising, because many earlier studies concluded that saw palmetto is effective against BPH. However, he pointed out a number of differences between the current study and earlier research: prior studies were generally small in size and short in duration; the majority of them did not use the standard symptom score for assessing the severity of BPH; and previous trials may have not created a placebo that convincingly duplicates saw palmetto’s strong smell and taste.

Dr. Bent cautioned that while the study is strongly indicative, it is not conclusive, and future studies should focus on careful blinding and higher doses of the herb.