What is Black Cohosh?
Black cohosh (known as both Actaea racemosa and Cimicifuga
racemosa), a member of the buttercup family, is a perennial plant that is
native to North America. Other common names include black snakeroot, bugbane,
bugwort, rattleroot, rattletop, rattleweed, and macrotys. Insects avoid it,
which accounts for some of these common names.
Historical Use
Black cohosh was used in North American Indian medicine for malaise,
gynecological disorders, kidney disorders, malaria, rheumatism, and sore throat.
It was also used for colds, cough, constipation, hives, and backache and to
induce lactation.
In 19th-century America, black cohosh was a home remedy used
for rheumatism and fever, as a diuretic, and to bring on menstruation. It was
extremely popular among a group of alternative practitioners who called black
cohosh "macrotys" and prescribed it for rheumatism, lung conditions, neurological
conditions, and conditions that affected women's reproductive organs (including
menstrual problems, inflammation of the uterus or ovaries, infertility,
threatened miscarriage, and relief of labor pains).
Black cohosh became a popular treatment for women’s health
issues in Europe in the mid-1950s. Since that time, black cohosh has commonly
been used to treat symptoms of menopause, premenstrual syndrome (PMS), painful
menstruation, acne, weakened bones (osteoporosis), and for starting labor in pregnant
women. Black cohosh has also been tried for a lot of additional uses, such as anxiety,
rheumatism, fever, sore throat, and cough, but it is not often used for these
purposes these days.
Possible Mechanism
The root of black cohosh is used for medicinal purposes.
Black cohosh root contains several chemicals that might have effects in the
body. Some of these chemicals work on the immune system and might affect the
body’s defenses against diseases. Some might help the body to reduce
inflammation. Other chemicals in black cohosh root might work in nerves and in
the brain. These chemicals might work similar to another chemical in the brain
called serotonin. Scientists call this type of chemical a neurotransmitter
because it helps the brain send messages to other parts of the body.
Black cohosh root also seems to have some effects similar to the female hormone, estrogen. In some parts of the body, black cohosh might increase the effects of estrogen. In other parts of the body, black cohosh might decrease the effects of estrogen. Estrogen itself has various effects in different parts of the body. Estrogen also has different effects in people at different stages of life. Black cohosh should not be thought of as an “herbal estrogen” or a substitute for estrogen. It is more accurate to think of it as an herb that acts similar to estrogen in some people.
The most recent investigations do not support an
estrogen-receptor mediated theory as a plausible mechanism of action of black
cohosh. Alternate mechanisms of action have been proposed, such as a
dopaminergic or serotoneric effects, and pharmacologic investigations in these
areas are currently underway.
Does it Work?
December of 2006, a large study looking at the effects of
several herbal-combination regimens and menopausal hormone therapy concluded
that black cohosh was no better than placebo in reducing menopausal hot
flashes. Results of this study — called the Herbal Alternatives for Menopause
Trial (HALT) and jointly funded by the National Center for Complementary and
Alternative Medicine (NCCAM) at the National Institutes of Health — were a huge
disappointment, but as the executive director of the American Botanical Council
put it, “definitely not the last word.” He pointed out that not only was the study
design flawed, but the authors omitted data showing a host of beneficial
secondary effects when they published their findings in the Annals of
Internal Medicine. While the mainstream media leapt on the findings as
conclusive, the reality is that the results of this study are entirely
inconsistent with the history of findings on black cohosh and menopause, and
should be placed in context alongside them.
Looking on the history of research, although some studies’
results suggest that black cohosh may help relieve menopausal symptoms, other
studies results do not. Multiple studies of black cohosh have yielded
conflicting data, in part because of lack of rigor in study design and short
study duration (6 months or less). In addition, interpretation of these studies
is complicated by the fact that different amounts of black cohosh from
different sources were used in the various studies and their outcome measures
were different.
To date, the effects of black cohosh have been studied on
thousands of menopausal women, with the preponderance of evidence of slight
favor of its benefit–risk ratio. When women rank their menopausal symptoms
using two different assessment measures known as the Kupperman Index and
the Menopause Rating Scale, black cohosh has more consistently delivered
better results than many conventional therapies such as hormonal drugs and
antidepressants in assuaging hot flashes, mood swings, vaginal atrophy,
depression, anxiety and other menopausal symptoms — without increasing their
risk of uterine or breast cancer.
Side Effects
Black cohosh can cause stomach discomfort and headaches. Clinical
trials comparing estrogens with black cohosh preparations have shown a low incidence
of adverse effects associated with black cohosh; headaches, gastric complaints,
heaviness in the legs, and weight problems were the main adverse effects noted.
As said, black cohosh usually has not been used for long periods, and published studies have followed women for only 6 months or less. Recently, a large study that followed postmenopausal women taking combined estrogen and progestin for an average of 5.2 years showed a small but significant increase in the risk of certain diseases, demonstrating the importance of long-term studies in revealing risks that may not be apparent in shorter studies. If black cohosh is estrogenic, long-term use may adversely affect uterine or breast tissue. No studies have been published on long-term safety in humans, particularly regarding abnormal stimulation of cells in the endometrium or breast.
As said, black cohosh usually has not been used for long periods, and published studies have followed women for only 6 months or less. Recently, a large study that followed postmenopausal women taking combined estrogen and progestin for an average of 5.2 years showed a small but significant increase in the risk of certain diseases, demonstrating the importance of long-term studies in revealing risks that may not be apparent in shorter studies. If black cohosh is estrogenic, long-term use may adversely affect uterine or breast tissue. No studies have been published on long-term safety in humans, particularly regarding abnormal stimulation of cells in the endometrium or breast.
Liver damage has been reported in a few individuals using black cohosh, but millions of people have taken the herb without apparent adverse health effects. While studies of black cohosh have not provided scientific evidence to show that the herb causes liver damage, at least one country has added a warning to the label of all products containing black cohosh, stating that it may cause harm to the liver of some individuals and should not be used without medical supervision.
In the United States, the U.S. Pharmacopeia (the standards-setting organization for foods and drugs) advises that black cohosh products be labeled with the following cautionary statement: "Discontinue use and consult a healthcare practitioner if you have a liver disorder or develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice"
Regulatory Status of Black Cohosh in the United States?
In the United States, black cohosh is sold as a dietary
supplement, and dietary supplements are regulated as foods, not drugs.
Manufacturers do not have to provide the Food and Drug Administration (FDA)
with evidence that dietary supplements are effective or safe before marketing.
Because dietary supplements are not always tested for manufacturing
consistency, the composition may vary considerably from one lot to another.
Dosage and
Consumption
Black cohosh can be taken in various forms: as an extract in
an alcohol-based or water-based tincture, as a tea infusion, or in tablets or
capsules formed from the dried powder. If you decide to use black cohosh on its
own, however, for maximal therapeutic benefit, the product label should state
that it’s standardized to a minimum of 2% total triterpene glycosides
(calculated as 26-deoxyactein — this is sometimes mistakenly listed as
27–deoxyactein, so be sure to check the label). In addition, black cohosh is
generally a “wildcrafted” species, meaning it’s grown and harvested in the wild
rather than being farmed. As with other stand-alone herbal remedies, you may
want to check the label to be sure the ingredients are either ecologically
wildcrafted or certified organically grown.
Optimal dosage will depend on your unique physiology; some
practitioners recommend women start with a daily dose of 40 mg of the dried
root powder twice a day, while others suggest 20 mg twice daily. You may want
to consult with an herbalist or naturopath in determining which black cohosh
product will work best for you as an individual.
Sources and Additional
Information: