Women who took the herb black cohosh to manage menopause symptoms were less likely to have breast cancer than women who did not take the nutrient, and black cohosh appeared safe for breast, uterine and general health in two new studies.
Researchers from the University of Pennsylvania School of Medicine, Philadelphia, recruited 949 women with breast cancer and 1,524 women of similar age without breast cancer and analyzed which herbal preparations the women were taking to manage menopause symptoms. The doctors determined that 5.4% of African American women and 2.0% of European women had used or were using herbal preparations containing black cohosh. Comparing the black cohosh users to all other women, and accounting for lifestyle and other risk factors, the scientists determined that women who took black cohosh were 61% less likely to have breast cancer than women who did not take black cohosh.
In an open (not placebo-controlled) drug-safety study from the Karolinska University Hospital in Stockholm, Sweden, published in the February 2007 issue of Menopause, researchers recruited 65 healthy, naturally—not surgically induced—postmenopausal women who took 40 mg of black cohosh extract per day for six months. At the start and end of the study, doctors took mammograms to determine breast tissue density and biopsies for breast cell growth, both of which can signal breast cancer risk. Doctors also measured the thickness of the endometrial lining of the uterus, another cancer signal. At the end of the study, the women had no increase in breast tissue density or breast cell growth and no endometrial thickening. Doctors concluded that black cohosh did not cause adverse effects on breast tissue and did not raise any endometrial or general safety concerns during six months of treatment.