More than two centuries ago, Native Americans discovered that the root of the black cohosh plant (Actaea racemosa, formerly known as Cimicifuga racemosa) helped relieve menstrual cramps and symptoms of menopause, such as hot flashes, irritability, mood swings, and sleep disturbances. Today, people use black cohosh for these same reasons. In fact, the herb has been widely used for more than 40 years in Europe and is approved in Germany for premenstrual discomfort, painful menstruation, and menopausal symptoms.
Quite a few clinical studies confirm that the use of black cohosh is effective for improving menopausal symptoms, although some have found no improvement. Early German studies found black cohosh improved physical and psychological menopausal symptoms, including anxiety, hot flashes, night sweats, and vaginal dryness.
In a clinical study of 120 women with the menopausal symptoms, black cohosh was more effective in relieving hot flashes and night sweats than the antidepressant fluxetine (Prozac).
Given the results of most clinical studies, many experts conclude that black cohosh may be a safe and effective alternative for women who cannot or will not take hormonal replacement therapy (HRT) for menopause. A 2010 review by researchers found that black cohosh provided a 26% reduction in hot flashes and night sweats (also known as vasomotor symptoms).
However, experts do not agree on the effectiveness and safety of using black cohosh to relieve symptoms of menopause. The American College of Obstetricians and Gynecologists (ACOG) reports that many of the early studies were poorly designed and did not evaluate the safety and effectiveness of black cohosh beyond 6 months of use. A 2009 study reported that black cohosh did not relieve hot flashes any more than placebo did. Still, the ACOG recognizes the value of black cohosh for menopausal symptoms.
Until further studies are conducted, some doctors recommend only short-term (less than 6 months) use of this herb for the relief of hot flashes.
Hot Flashes Related to Breast Cancer Treatments
Breast cancer medications such as tamoxifen (Nolvadex) can cause hot flashes. While many breast cancer patients may take black cohosh to reduce the number and intensity of hot flashes, two well-designed studies concluded that the herb is no more effective than placebo. In addition, Yale researchers report that herbal medicines such as black cohosh may interfere with common breast cancer treatments, such as radiation and cancer therapy drugs.
There has been some concern that black cohosh may contain plant based estrogens, or phytoestrogens, which can stimulate the growth of breast tumors. However, a case-control clinical study of 949 breast cancer cases and 1,524 controls found that black cohosh use had significant protective effects against breast cancer development. More research is needed. Patients with a history of breast cancer, risk factors for breast cancer, or who are actively engaged in breast cancer treatment, should talk to their doctor before taking black cohosh.
Preliminary studies suggest that black cohosh may help reduce inflammation associated osteoarthritis and rheumatoid arthritis. In a review of scientific studies, researchers concluded that a combination of black cohosh, willow bark (Salix spp.), sarsaparilla (Smilax spp.), guaiacum (Guaiacum officinale) resin, and poplar bark (Populus tremuloides) may help relieve symptoms of osteoarthritis. However, there is not enough human research to make a clear recommendation about the use of black cohosh alone for arthritis.
Laboratory studies have found that plant based estrogens (called phytoestrogens) in black cohosh may inhibit bone loss, such as seen with osteoporosis. More research is needed.
The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs contain active substances that can trigger side effects and interact with other herbs, supplements, or medications. For these reasons, you should take herbs only under the supervision of a health care provider.
Some people who take high doses of black cohosh report side effects, including abdominal pain, diarrhea, dizziness, headaches, joint pains, nausea, slow heart rate, tremors, visual dimness, vomiting, and weight gain. You should not use black cohosh if you have a hormone-sensitive condition, such as breast cancer, endometriosis, ovarian cancer, uterine cancer, or fibroid tumors.
It is not clear whether black cohosh stimulates the growth of breast cancer cells or inhibits their growth. Research has been limited and has produced mixed results. Women with a history of breast cancer, and those at a high risk for developing breast cancer (for example, a strong family history like a mother or sister with breast cancer), should not take black cohosh without talking to a health care provider.
A few cases of liver toxicity have been reported, but a direct association with the ingestion of black cohosh has not been demonstrated. However, you should not use black cohosh if you have liver damage or drink alcohol in excessive quantities. Pregnant and breastfeeding women should avoid black cohosh as the herb may stimulate contractions and lead to premature labor.
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