A leading nonprofit herbal science organization challenges the conclusions of an unpublished study on the effect of black cohosh for treating symptoms of menopause.
The American Botanical Council (ABC) responded to a study conducted by researchers at the Mayo Clinic in Scottsdale, Ariz. The researchers concluded that black cohosh pills used in their trial on 132 women did not provide any noticeable benefit for menopause symptoms when compared to placebo. The findings are reported at a meeting of the American Society of Clinical Oncology in Orlando, Fla.
ABC pointed out the weaknesses and problems with the trial described in the press release from Mayo Clinic. It said that a full report describing the trial’s results has not yet been completed and subjected to the necessary peer-review process required for publication in a reputable medical journal.
Further, the trial was only four weeks and was probably too short to measure any effect from the product tested, since most clinical trials on black cohosh have run for three to six months.
“Most of the clinical trials published to date on black cohosh have demonstrated positive results in helping to treat various symptoms of menopause,” said Mark Blumenthal, founder and executive director of ABC. “The evidence supporting the benefits and relative safety of this traditional herb is becoming increasingly clear.”
Menopausal symptoms include the well-known hot flashes (sometimes called hot flushes), as well as nighttime perspiration, vaginal dryness, and mood swings. According to ABC, several European black cohosh preparations have been shown to be effective in alleviating these conditions.
At least 14 clinical trials on black cohosh preparations support their safety and efficacy in treating menopause-related symptoms, including hot flashes, perspiration, and mood swings, according to Gail Mahady, PhD, assistant professor of pharmacy practice at the University of Illinois at Chicago, who has reviewed most of the research on black cohosh for a monograph for the World Health Organization.
Black cohosh, also known by its scientific names (Actaea racemosa and Cimicifuga racemosa) is a member of the buttercup family (Ranunculaceae) native to the eastern United States. The roots and rhizomes (lateral roots) of the herb have a long history of use by American Indian tribes to deal with genitourinary complaints in women. An extract of black cohosh has been used in German clinical practice since the mid-1950s with safe and effective results, and black cohosh preparations have been approved by the German government as nonprescription medications for treatment of menopausal symptoms.
Black cohosh has become increasingly popular as a natural alternative to hormone replacement therapy (HRT). Black cohosh preparations ranked eighth of all herbal supplements sold in mainstream retail outlets in 2004, according to data from Information Resources in Chicago as reported in the current issue of HerbalGram, ABC’s quarterly journal. Total retail sales of black cohosh in all channels of trade are difficult to estimate, but may be as high as $76 million in 2003, a jump of about 28 percent in sales from the previous year, according to Nutrition Business Journal.
Source: American Botanical Council, www.herbalgram.org
1. Mayo Clinic Researchers Report on Effectiveness of Treatments for Hot Flashes [press release]. Scottsdale, AZ: Mayo Clinic; May 15, 2005
2. Osmers R, Friede M, Liske E, Schnitker J, Freudenstein J, Henneicke-von Zepelin H-H. Efficacy and Safety of Isopropanolic Black Cohosh Extract for Climacteric Symptoms. Obstet Gynecol 2005;105:1074–83