Saw palmetto, a widely used herbal dietary supplement, does not reduce urinary problems associated with prostate enlargement any better than a placebo, according to research funded by the National Institutes of Health. The study was published Sept. 28 in the Journal of the American Medical Association.
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. More than half of men in their 60s, and up to 90 percent in their 70s and 80s, have symptoms of BPH.
The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Center for Complementary and Alternative Medicine (NCCAM) and the Office of Dietary Supplements (ODS) supported the study. All are part of the NIH.
According to Robert A. Star, M.D., director of the NIDDK's Division of Kidney, Urologic and Hematologic Diseases, the current study met an important need for rigorous evaluation of standard and higher doses of saw palmetto. The trial also confirmed results of the earlier NIDDK- and NCCAM-sponsored Saw Palmetto Trial for Enlarged Prostates (STEP), which found that a standard daily dose of 320 milligrams 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 Star. "We were disappointed to find that higher doses of saw palmetto did not improve symptoms more than placebo."
Josephine P. Briggs, M.D., director of NCCAM, added that this study further illustrates the importance of conducting research on botanical products that are used extensively by the general public.
"This was a well-designed study that addressed limitations of earlier, smaller trials – it was a multicenter study with a larger sample size and tested different doses of a carefully analyzed saw palmetto product," Briggs said. "The NIH is committed to bringing rigorous science to the study of natural products and to building the evidence base that can guide consumer decisions."
The study was a double-blind randomized placebo-controlled clinical trial conducted at 11 North American clinical sites from June 2008 to October 2010. A cohort of 369 men aged 45 years or older participated, each with a peak urine flow rate of at least four milliliters per second at the beginning of the study -- which is less than normal. Also, all had an American Urological Association Symptom Index (AUASI) score of between eight and 24 -- a lower score is better. The AUASI score ranges from zero to 35. Escalating doses of saw palmetto or placebo were given, starting at one, then two, and then three pills of 320 milligrams per day, with dose increases at 24 and 48 weeks.
The study measured the differences between the AUASI score at the start of the trial and after 72 weeks of treatment. Secondary measures included improvements in frequency, nocturia (nighttime urination), peak urine flow, prostate-specific antigen (PSA) level, sexual function, incontinence and sleep quality.
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 group average change in AUASI score from baseline to 72 weeks between the saw palmetto and placebo groups was 0.79 points, favoring placebo. Saw palmetto was not more effective than placebo in reducing urinary symptoms for any of the secondary outcomes.
According to Joseph M. Betz, Ph.D., director of the Analytical Methods and Reference Materials program at ODS and a study co-author, the study used a very well-characterized saw palmetto product. Through batch testing, study investigators took extreme care to ensure that the composition of the supplement was consistent over the whole study.
"Saw palmetto and other herbs are often manufactured in different ways, so no two brands are likely to have the same composition," Betz said.
Rottapharm/Madaus, Cologne, Germany, donated the saw palmetto extract and matching placebo used in the study.
For more information on the trial, search for NCT00603304 at www.clinicaltrials.gov. Learn about BPH at http://kidney.niddk.nih.gov/kudiseases/pubs/prostateenlargement.
To interview an NIH official or scientist, contact:
Bill Polglase, NIDDK, 301-435-8115 or 301-496-3583(BPH and urinary symptoms)
NCCAM Press, NCCAM, 301-496-7790 (complementary and alternative medicine)
Kelli Marciel, ODS, 301-496-4819 (dietary supplements)
The NIDDK, a component of the NIH, conducts and supports research on diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition and obesity; and kidney, urologic and hematologic diseases. Spanning the full spectrum of medicine and afflicting people of all ages and ethnic groups, these diseases encompass some of the most common, severe and disabling conditions affecting Americans. For more information about the NIDDK and its programs, see www.niddk.nih.gov.
The NCCAM's mission is to define, through rigorous scientific investigation, the usefulness and safety of complementary and alternative medicine (CAM) interventions and their roles in improving health and health care. For additional information, call NCCAM's Clearinghouse toll free at 1-888-644-6226, or visit the NCCAM Web site at nccam.nih.gov.
The mission of the NIH ODS is to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, stimulating and supporting research, disseminating research results, and educating the public to foster an enhanced quality of life and health for the U.S. population. For additional information about ODS, visit ods.od.nih.gov.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
Bill Polglase | EurekAlert!
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering