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, which 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.
Katherine M. Newton, Ph.D., of the Group Health Center for Health Studies, Seattle, and the University of Washington, and colleagues, conducted the HALT study. 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, MD "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 because most previous studies looked only at postmenopausal women, who tend to have fewer symptoms than women going through menopause.
"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, MD, "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, though few have been evaluated in randomized trials."