A male with an enlarged prostate that causes urinary symptoms does not appear to benefit from higher dosages of saw palmetto, a fruit extract said to help in such cases, researchers from Massachusetts General Hospital, Boston, USA, reported in JAMA (Journal of the American Medical Association).
The authors wrote:
“Benign prostatic hyperplasia [BPH; an enlarged prostate gland] is a common cause of bothersome lower urinary tract symptoms (LUTS) among older men and may be treated with medications, minimally invasive therapies, or surgery. Plant extracts are also widely used for LUTS in the United States and Europe. The most common are extracts of the fruit of the saw palmetto dwarf palm tree.”
A survey carried out in 2007 in the United States found that 17.7% of male adults reported having used some kind of natural product within the previous thirty days, and 5.1% had consumed saw palmetto. A number of human studies have questioned the efficacy of saw palmetto for the treatment of lower urinary tract symptoms, which may include urination hesitancy, urgency, or frequency.
Michael J. Barry, M.D., and team set out to find out whether a standard saw palmetto extract dosage when increased to double and then triple the daily dose over a period of 72 weeks might help symptoms of LUTS linked to BPH. The placebo-controlled, randomized trial was conducted at 11 different clinical sites throughout North America from June 2008 through October 2010. It involved 369 males aged at least 45 years.
They all had a specific minimum peak urinary flow rate and an AUASI score of between 8 and 24 after two screening visits. AUASI stands for American Urological Association Symptom Index – a self-administered 7-item index which assesses frequency of LUTS, ranging from 0 to 35 points.
The volunteers were randomly selected to received 1, 2, and then 3 doses of saw palmetto extract 320 mg/d, or a placebo. The dosages were increased at weeks 24 and 48.
At the end of the 72 weeks, the researchers found that AUASI scores:
- Dropped 2.20 (average) points in the saw palmetto extract group
- And 2.99 points in the placebo group
The placebo did better than the saw palmetto – a 0.79 difference in the placebo’s favor.
The authors explained:
“The proportion of participants achieving a 3-point decrease in AUASI score at 72 weeks was 42.6 percent in the saw palmetto extract group and 44.2 percent in the placebo group. In addition, the analysis of dose response also showed no greater improvement with saw palmetto extract vs. placebo at any dose level.”
Saw palmetto fared no better than the placebo for other secondary outcomes, such as nocturia, sexual function, continence, sleep quality, urinary bother, and prostatitis symptoms.
The scientists reported no clearly attributable adverse effects.
The authors wrote:
“In conclusion, we found that saw palmetto extract used at up to 3 times the standard daily dose had no greater effect than placebo on improving lower urinary symptoms or other outcomes related to BPH.”
Written by Christian Nordqvist