Herbal supplement fails to relieve hot flashes in large NIH trial

December 18, 2006

The herbal supplement black cohosh, whether used alone or with other botanical supplements, did not relieve hot flashes in postmenopausal women or those approaching menopause, who participated in the Herbal Alternatives (HALT) for Menopause Study, according to results from the clinical trial. The research, funded by the National Institutes of Health (NIH), found that women using menopausal hormone therapy, however, did receive significant relief from their hot flashes and night sweats.

The 12-month randomized, double-blind, placebo-controlled trial, compared several herbal regimens and menopausal hormone therapy (estrogen with or without progesterone) to placebo in women ages 45 to 55.

The HALT Study was conducted by Katherine M. Newton, Ph.D., of the Group Health Center for Health Studies, Seattle, and the University of Washington, and colleagues. The National Institute on Aging (NIA) and the National Center for Complementary and Alternative Medicine (NCCAM), two components of NIH, funded the research. The findings are reported in the Dec.19, 2006, issue of Annals of Internal Medicine.

"In recent years, scientific studies have raised questions about the safety of certain types of menopausal hormone therapy in some women. Interest has grown in alternatives to hormones, including herbal supplements, for controlling hot flashes and other symptoms of menopause," says NIA Director Richard J. Hodes, M.D. "Testing the safety and efficacy of various treatments in randomized clinical trials such as HALT is critically important in helping women in mid-life and their doctors to make informed choices."

Three-hundred and fifty-one women, ages 45 to 55, took part in the HALT Study, conducted at the Seattle-based Group Health Center for Health Studies. Each participant was experiencing at least two hot flashes and/or night sweats daily at the start of the study. The women were approaching menopause, having missed at least one menstrual cycle in the preceding 12 months, or were postmenopausal, having had no menstrual cycle in at least 12 months. Researchers included women who were perimenopausal (or in the menopause transition) because most previous studies looked only at postmenopausal women, who tend to have fewer symptoms than women going through menopause.

Initially, the women were randomly assigned to receive one of five therapies: Participants met with clinic staff at three, six, and 12 months after the beginning of the study and also received monthly telephone calls from study nurses. The women were recruited into the study from May 2001 through August 2003. When the first reports from the Women's Health Initiative (WHI) in July 2002 raised possible concerns about the safety of menopausal hormone therapy*, researchers informed all women in the study about those findings and offered them the opportunity to take part in a study without a menopausal hormone therapy group. Most women consented to continue participation in the trial. All participants were informed about subsequent WHI publications, and later recruits were enrolled in the trial without the option of a menopausal hormone therapy group.

Newton and colleagues found no significant difference between the number of daily hot flashes and/or night sweats in any of the herbal supplement groups when compared to the placebo group. At the end of one year, the average difference was less than 0.6 symptom per day. However, the average difference at one year in symptoms between the menopausal hormone therapy and placebo group was significant--4.06 fewer symptoms per day among women receiving hormones.

"While this study found that black cohosh alone or with other herbs did not reduce menopausal hot flashes," said NCCAM Acting Director Ruth L. Kirschstein, M.D., "it highlights the importance of studying herbs using well-designed research to find out what works and what does not. With this information women and their physicians can have a meaningful discussion of complementary and alternative medicine approaches to menopause."

According to the 2000 census, about two million women turn 50 every year, and 51 is the average age of menopause. Many of these women experience menopausal symptoms of varying intensity. Some seek relief from their symptoms. Newton and colleagues previously noted that alternatives to menopausal hormone therapy, including over-the-counter supplements and phytoestrogens, "are sometimes assumed to be safer than ET/EPT (i.e., menopausal hormone therapy), though few have been evaluated in randomized trials."

The NIA leads the federal effort supporting and conducting research on aging and the medical, social and behavioral issues of older people, including Alzheimer's disease and age-related cognitive decline. General information on research and aging, including menopause, is available on the NIA's website at www.nia.nih.gov or by calling the NIA Information Center toll-free at 1-800-222-2225.
-end-
The primary mission of NCCAM is to explore complementary and alternative healing practices in the context of rigorous science, train researchers in the field, and disseminate authoritative information to the public and professionals. For additional information, visit the NCCAM website at www.nccam.nih.gov, or call the NCCAM Information Clearinghouse toll-free at 1-888-644-6226.

The National Institutes of Health (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. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

NIH/National Institute on Aging

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