Nan Mei, PhD
The December 2022 EMM Editor’s Choice Article is “A cross-sectional clinical study in women to investigate possible genotoxicity and hematological abnormalities related to the use of black cohosh botanical dietary supplements” (https://onlinelibrary.wiley.com/doi/10.1002/em.22516) by Smith-Roe SL, Garantziotis S, Church RL, Bemis JC, Torous DK, Shepard KG, Hobbs CA, Waidyanatha S, Mutlu E, Shockley KR, Kissling GE, McBride SJ, Xie G, Cristy T, Pierfelice J, Witt KL.
Black cohosh, a North American species of Actaea racemosa, is a tall perennial with a woody rootstock, native to Eastern North America, found from southern Ontario to Georgia and from Wisconsin to Arkansas. Black cohosh is one of the most popular botanical dietary supplements used in the U.S. and Europe for relieving menopausal symptoms. According to the most current estimates, black cohosh was the 20th top-selling herbal supplement in the mainstream U.S. market in 2021, with sales of $23.8 million (excluding sales in natural retail stores and direct sales). Black cohosh has been used traditionally by Native Americans for the treatment of a variety of disorders, including various conditions specific to women. Contemporary uses of black cohosh include relieving menstrual and perimenopausal symptoms in women, as an alternative to estogen-based therapy. However, recent studies have reported that black cohosh extract (BCE) showed limited efficacy for relieving menopausal symptoms. In addition, adverse events, including isolated reports of hepatotoxicity, associated with its consumption raised concerns. Therefore, black cohosh was nominated by the National Cancer Institute (NCI) to the National Toxicology Program (NTP) for toxicological evaluation. While the NTP 2-year chronic carcinogenicity study with black cohosh is ongoing, results from short-term in vivo and in vitro studies demonstrated that BCE induced significant increases in the frequency of micronucleated red blood cells in female rodents and in cultured human TK6 lymphoblastoid cells, indicative of chromosomal damage.
The authors designed a pilot study to investigate a variety of hematological endpoints in women who use BCE supplements and women who do not. Twenty-three women were enrolled in the BCE-exposed group and 28 in the BCE-naïve group. The BCE supplements used by these 23 women were diverse and included pills, root powers, and liquid formulations. Dosages ranged from 40 to 1620 mg/day and duration of use ranged from 3 months to 16 years. Chromatographic profiles of the BCE samples were used to create a dendogram. Eighteen of the samples clustered together, indicating chemical similarity, while the remaining 5 showed distinct differences in chemical analysis. Blood samples from all study participants were analyzed for genotoxicity and hematological characteristics. Flow cytometric analysis of samples revealed no increases in micronucleus frequencies in either group and no hematological abnormalities were detected in women who used BCE supplements. As the authors indicated, the power to detect significant differences between the two groups in this cross-sectional study was limited by several cofounding factors including the diversity of BCE products and duration of use. Therefore, the authors suggested that additional studies employing prospective (i.e., “cohort”) designs may provide a more definitive assessment of the safety of BCE supplements.
