BLACK COHOSH: Benefits, Side Effects, Uses, Dosage, Warnings?
Common names: black cohosh, black cohosh, black cohosh root, squaw.
Botanical names: Cimicifuga racemosa (formerly), Actaea racemosa (current name), buttercup family.
English name: black cohosh .
Parts used: rhizome and roots.
Habitat and origin: this plant, which can grow up to 2.5 m tall, is native to southeastern Canada and the northeastern United States, where it grows in shade of undergrowth.
Reduce the symptoms of menopause.
See legend of symbols
Reduce hot flashes secondary to treatment against breast cancer.
Reduce the symptoms of menopause; relieve PMS and menstrual pain.
Dosage of black cohosh
Reduction of menopausal symptoms
Standardized extract . Standardized extracts are often in the form of 20 mg tablets containing 27 mg of 1-deoxyactein. Take 1 to 2 tablets (equivalent to 1 mg to 2 mg of deoxyactein), 2 times per day. It is this type of extract that was most often used in clinical studies. There are also standardized to contain 2.5% triterpene glycosides extracts; triterpene glycosides are a group of substances for which the deoxyactein belongs.
Dye (1: 10 to 60% ethanol). Take 0.5 ml to 2 ml per day.
Dried rhizome and roots . Take up to 40 mg daily.
Decoction . Boil 40 mg of dried root and rhizome in 150 ml of water. Strain before drinking.
Please allow 4 to 6 weeks before feeling the effects of the plant.
History of black cohosh
Native Americans were the first to make a medicinal use of black cohosh . They used to fight menstrual pain and those of childbirth, but also as a gargle for sore throat and to treat rheumatism and snake bites. The plant was adopted by European settlers and quickly made part of the United States Pharmacopoeia.
In 1875, a popular remedy for women, Lydia Pinkham's Vegetable Compound, a sensation in the United States; in the original composition of the remedy used to relieve menstrual stress and nervous tension, black cohosh was in a good place. In the XIX th century, eclectic physicians used in gynecology , but also to treat arthritis and rheumatism.
The Germans discovered the virtues of the plant in the late XIX th century. By the middle of XX th century, German physicians began using a standardized extract of black cohosh as an alternative to hormone replacement therapy in postmenopausal women.
Interest in the black cohosh as well as other reputable relieve the symptoms of plants menopause , increased significantly since the publication in 2002 of the results of an American major study (Women's Health Inititiative ). During this test, followed 16,608 women who took either a placebo or treatment of hormone therapy of estrogen and progestin. After 5 years the study was discontinued because this hormone therapy had an increased risk of breast cancer and coronary heart disease 1 .
Research on black cohosh
Potential Effectiveness Menopause. before 1970 in Europe, 1465 Clinical observations on black cohosh have been published in 14 articles. The main effects reported were reduced hot flashes , excessive sweating, sleep disturbances, depression and anxiety 2 .
Several clinical studies have been conducted since then, but their results are contradictory. Summaries published from these studies conclude that if 'the black cohosh may be useful in reducing the symptoms of menopause, including hot flashes and mood disorders, evidence of its effectiveness remains to be demonstrated 3-7, 52 . Those same summaries highlight the methodological weaknesses of these studies, particularly the lack of standardized preparations used; cohosh sometimes being the component of a mixture of several crops. On the other hand, the subjectivity of some measured parameters, such as psychological symptoms, introduced a significant degree of uncertainty in the results.
When black cohosh is used alone, the observed effects varied across studies. It can reduce the symptoms of menopause 14, 53 , sometimes only in women with more severe symptoms 13 . For others, it has no effect 11, 12, 22, 54 .
However, compared to conventional treatment, black cohosh has proven as effective as tibolone 9 (a treatment used in Europe but not in North America) or other hormonal therapies 55 . It has also been more effective than fluoxetine 8 (an antidepressant medication).
The black cohosh is sometimes combined with St. John's wort to fight against mood disorders associated with menopause, such as depression and anxiety. Three independent studies on the effectiveness of such a mixture have measured a significant reduction in symptoms of menopause psychologically but also physically 10, 17, 18 . Nevertheless, it is impossible to determine the relative share St. John's wort in the observed effects. Especially since the only black cohosh is less effective 10 or ineffective against anxiety 56 .
Note. In most studies have used the commercial preparation Remifemin ® , a standardized extract of black cohosh (1% actein).
The Commission E and the World Health Organization recognize the effectiveness of black cohosh against the symptoms of menopause . Commission E also recognizes the effectiveness of plant for the relief of premenstrual discomfort and menstrual pain, but no clinical studies are listed in the PubMed database on it.
Uncertain effectiveness Flushing after breast cancer. Women who have been treated for breast cancer often suffer from hot flashes similar to those that occur at the menopause. Three clinical studies have been conducted with women who have suffered from breast cancer. Two studies without placebo group saw a reduction in hot flashes and intensity 20,21 . The placebo group showed no effect of black cohosh 22 . However, in the latter, black cohosh appeared to have a greater than placebo in reducing perspiration when flushing effect.
Note. During 2007, the authors of a synthesis and an observational study concluded that the black cohosh taken not safe for women with breast cancer 25-27 .
Estrogenic or not? It was believed until recently that black cohosh had estrogenic activity, thus raising concerns about its use by women who have had breast cancer . Several recent experimental studies for doubt that the plant has such an effect 28-34 . In fact, it would have a rather antiestrogenic effect and an inhibitory effect on breast cancer cells, at least in vitro 35-39 .
During a meeting organized by the National Center for Complementary and Alternative Medicine in November 2004, it was concluded that black cohosh had no estrogenic effect 40 . Instead, it would act on the serotonin receptor 6 . Moreover, in a recent study for 1 year among 400 women, we measured the effect of a black cohosh on the endometrium participating extract: no hormonal effects were observed, which According to the authors, shows that black cohosh is a safe and effective treatment against the symptoms of menopause 41 .
Do not confuse black cohosh ( Actaea racemosa ) with blue cohosh ( Caulophyllum thalictroides ) or white ( Actaea alba ) that does not have the same properties, which are both toxic .
Pregnancy and lactation.
Occasionally: gastrointestinal discomfort, headache, dizziness, feeling of heaviness in the legs, weight gain, spasms.
Cases of liver toxicity related to taking black cohosh has been reported. According to experts from the National Center for Complementary and Alternative Medicine, the link between cause and effect has not been established (patients taking other medicines or plants) and black cohosh does not contain toxic ingredient the liver, which would indicate a contamination of the final product rather than toxicity of the plant itself 42 . It may also be they a problem of quality control related to the presence in some supplements, Chinese rather than black cohosh cohosh 50 . During February and July 2006 respectively, the Australia and Britain have ruled that supplements containing black cohosh should display a warning about potential liver toxicity 43,44 . In August 2006, Health Canada issued an advisory warning advising caution in people taking black cohosh 45 . In 2010 an analysis of 69 cases of liver toxicity attributed to black cohosh, have occurred since 2002 in Australia, Canada, the United States and the European Union concluded that none of these cases have been caused directly and solely by the consumption of the plant 57 .
Attention. Six cases of serious liver injury were identified by Health Canada from January 2006 to March 2009, following the consumption of products containing black cohosh. In 3 cases, it was found after analysis that the product did not contain black cohosh, but related species 51 .
It is important to check the label of a natural health product has a Natural Product Number (NPN), certifying its safety, efficacy and quality standards meet Health Canada.
With plants or supplements
Data in vitro indicate that black cohosh may increase 46,47 or reduce 48 the effect of certain anticancer drugs. A clinical study was conducted with women who have survived breast cancer. These have taken for 1 year, a standardized extract of black cohosh (CR BNO 1055®) and 20 mg of tamoxifen (an anticancer drug). This trial did not reveal any adverse interaction between the 2 treatments. Instead of taking the extract of the plant has reduced flushing participants, a common consequence of the treatment of breast cancer 20 .
The opinion of our pharmacist
What about when a big budget new study contradicts what is known about a natural product?
Logically, a major study involving a number of participants over a long period of time, should give more accurate and reliable test results that shorter and smaller. Yes, but ...
In fact, this logic holds up if you forget to take the human factor into consideration. When a study lasting more than 3 months (as is the case of the study of Newton on black cohosh, which lasted one year), it is likely that participants receiving placebo realize that product they use is not effective.
Generally these patients begin to self-treat then. This behavior is well known in the scientific world. It becomes "measurable" about 3 months after the start of the study. Obviously, the fact that participants receiving placebo (inert by definition) are starting to use a form of treatment has a major impact on the final statistics of the study: the effect of "placebo" increases. Thus, the benchmark that the placebo effect is no longer valid, since it increases beyond reality. The therapeutic effect of the product studied thus decreases relative to that of placebo.
For example, if the test product is 63% effective in relieving hot flashes, it is logical to say that it is effective. By cons, if the placebo is 60% effective, the therapeutic product becomes ineffective by comparison, since it is only slightly more effective (3% higher) than placebo.
When the placebo effect at record efficiency, it is good to question the results of the study. It should then seriously consider the possibility that people who had to take an inert product took the initiative to deal with. In many cases, these people will choose to use the therapeutic product discussed (in the case of interest here, black cohosh). So, ultimately, what is being compared? The effect of the effect of black cohosh cohosh?
When you read very large studies that are intended to shed light "once for all" over the use of a natural product, always stand back and keep a bit of skepticism, especially when the results are in the opposite direction to what has been previously published.
Jean-Yves Dionne, BSc Pharm
On the shelves
In May 2006, researchers from Columbia University, the United States, published the results of analyzes of 11 supplements black cohosh sold in the United States 49 . Three of these products contained a variety of Asian and one black cohosh contained the Asian variety and the North American variety. These two varieties do not have the same profile or the same chemical properties and this is not desirable adulteration. Moreover, in products containing only the North American variety, the concentration of active ingredients suspected (triterpene glycosides) varied greatly.
The American independent laboratory ConsumerLab.com published in 2009, the results of tests on 12 products containing black cohosh. One such product was contaminated with lead in amounts that do not represent a danger and another did not show the composition of the product 50 .
Attention. few products containing black cohosh brands Swiss Herbal Health and Balance have been removed from the Canadian market between 2005 and 2009 their contamination related to black cohosh species caused poisoning resulting in liver disorders 51 .