Black cohosh (Cimicifuga racemosa) is without question the most
popular natural approach to menopausal symptoms. Its popularity
has been increasing in part because of all of the negative press
on Hormone Replacement Therapy. Specifically, last year the National
Institutes of Health (NIH) halted a major clinical trial designed
to help settle the debate over whether HRT benefits postmenopausal
women. This study was part of the Women's Health Initiative and
was published in The Journal of the American Medical Association.
The study concluded that the risks of taking combined estrogen and
progestin outweighed the benefits and increased the risk of stroke,
coronary heart disease and breast cancer. In case you missed it,
here were some of the more recent headlines on the potential dangers
of HRT:
August 8, 2003 - HRT Linked to Breast Cancer
A study published in the Lancet found that of more than one million
women in Britain aged 50 - 64 found that women who used HRT drugs
faced a 22% increased relative risk of death from breast cancer
compared to women who had never used hormones.
August 7, 2003 - HRT Could Increase Risk of Coronary Heart
Disease
Two studies in the New England Journal of Medicine found that
HRT does not protect women from heart disease, as doctors once
believed and one of the studies found that giving HRT to women
actually increases their risk of heart attack.
June 25, 2003 - HRT Linked to Breast Cancer
The Journal of the American Medical Association published two
studies that show HRT not only appears to stimulate the growth
of invasive breast cancers, but also makes it harder to spot the
potentially deadly tumors on mammograms.
May 27, 2003 - HRT Linked to Dementia
The May 28 issue of the Journal of the American Medical Association
cautions that post-menopausal women who took HRT have twice the
risk of developing Alzheimer's as those who do not. A related
study found that HRT also increases the risk of women sufferring
from stroke.
Some Bad Press on Black Cohosh
While black cohosh has an exceptional safety profile, two conflicting
reports came out last month. The first, a negative study entitled
"Black Cohosh and Breast Cancer a Dangerous Mix," was
picked up by almost all news services as it was headlined in newspapers
and on the television news. However, the second, a more comprehensive
study that provided tremendous reassurance on the safety of Black
cohosh in relieving menopausal symptoms was mostly ignored.
Is the reason to be concerned regarding the safety of black cohosh?
I don't believe so. Let's first take a look at the "negative"
study before we examine the weight of the evidence on black cohosh's
safety.
The yet to be published study in question was a twelve-month study
done at Duquesne University in Pittsburgh, on mice, not people.
The information regarding the detailed aspects of the study were
not released so not much is really known. What is known is that
the mice used were specially bred to be more likely to develop breast
cancer. Half were given a regular diet, while the other half had
a regular diet along with the equivalent of 40mg a day of black
cohosh extract, the amount generally used by women with menopausal
symptoms. Although the chance of getting cancer proved to be equal
in both groups, of the mice getting cancer, 27.1% of the mice that
had the black cohosh had their cancer spread into the lungs, while
10.9% of the mice not taking the Black cohosh had the cancer spread
to the lungs.
The results of this study were presented on July 12, 2003, at the
annual meeting of the American Association for Cancer Research held
in Washington. D.C. Immediately concern was voiced about women taking
Black cohosh. Lead researcher of this study, Vicki Davis, PhD, said
in a statement, "Our findings suggest that women who may be
at a high risk of having an undetected breast tumor, and certainly
those who do have breast cancer, should proceed with great caution
- or simply avoid - taking Black cohosh until we learn if there
are ways to circumvent these adverse effects."
Obviously, I don't agree with this position at all. First of all,
the effects of compounds in mice and humans can be quite different.
Second, there is considerable evidence of black cohosh's safety
and test tube studies on various types of human breast cancer cells
have shown an inhibitory effect - not a promotion of breast cancer
cell growth.
Is Black Cohosh Safe?
While the second report provided considerable more science it did
not seem to get the same degree of press coverage as the negative
study. The lead researcher was Tieraona Low Dog, MD is Clinical
Assistant Professor at the University of New Mexico and an advisor
to the NIH Center for Complementary and Alternative Medicine. Dr.
Low Dog concluded "This paper supports a growing body of evidence
on the safety of Black cohosh, an herb used by Native Americans
for centuries. The findings should reassure the increasing number
of women, who cannot or choose not to take HRT that safe options
exist to treat their menopausal symptoms."1
The opinion of Dr. Low Dog and her group was based on the most
comprehensive review of black cohosh safety data to date, and includes
pre-clinical and clinical research in estrogen-sensitive populations,
including women at risk for breast cancer and breast cancer survivors,
as well as human cell lines most relevant to breast cancer. This
review of the human use of black cohosh clearly contradicts the
theoretical concerns suggested by the study done with mice. In addition,
the BGA, the German equivalent to the FDA in the United States,
includes no contraindications or limitations of use for black cohosh
in cancer patients and another recent review concluded "that
extracts of black cohosh do not bind to the estrogen receptor, up-regulate
estrogen-dependent genes, or stimulate the growth of estrogen-dependent
tumors in animal models."2
The mechanism of action is thought to be via action on control centers
in the brain and vascular system rather than through any estrogenic
effect.3
The bottom line is that black cohosh has been substantially proven
to be safe and effective, even for those with breast cancer, and
in spite of the study with mice, to date there are no valid concerns
to worry about or warrant discontinuing its use.
A key consideration when using any herbal product, however, is
to make sure to use a high quality standardized extract from a reputable
manufacturer.
My Recommendations for Menopause
and Beyond
As I have previously described, I am a firm believer in building
a strong foundation. In that goal, there are three key dietary supplements
that I recommend to provide a strong foundation for a proper nutritional
supplement plan:
The specific multiple vitamin and mineral formula that I recommend
for women during and after menopause is MultiStart for Women Plus.
This formula was specially designed to provide full-spectrum for
menopause and beyond.
As far as a specific formula to address some of the challenges
of menopause, I recommend MenoSense from Natural Factors. This formula
was designed with my assistance by L Lorna Vanderhaeghe co-author
of the book No More HRT - Menopause: Treat the Cause. MenoSense
contains not only standardized black cohosh extract, but additional
herbal extracts and phytochemicals beneficial in supporting a smooth
transition through menopause.
How to Get Off HRT?
The best method for getting off any medication including HRT is
gradual reduction - a slow weaning process. Since menopause is not
a disease per se, you can stop cold turkey, but in my clinical experience
doing so is usually associated with rebound symptoms. In other words,
the severity of menopausal symptoms seemed to be much worse than
ever before. Black cohosh and other natural approaches are simply
not strong enough to lessen these symptoms sufficiently right off
the bat. Instead, it is best to begin your natural supplementation
program to support your health during menopause and after 2 weeks
of use cut the dosage of HRT in half. After two more weeks start
taking it every other day. After an additional two weeks discontinue
use.
How Long Can Black Cohosh Be Taken?
Although the German Commission E monograph has recommended that
treatment with black cohosh be limited to six months (the standard
recommendation for hormone replacement therapy as well), this recommendation
was made because the Commission did not feel that it was appropriate
for anyone to be taking an herbal product for any reason in an unsupervised
fashion not because of any real concern of toxicity.
Based upon detailed toxicology studies it appears the black cohosh
extract is appropriate at recommended levels for long-term continued
use. The no effect dosage in studies in a six-month chronic toxicity
study in rats was at 1,800 mg/kg body weight - or roughly 90 times
the human therapeutic dose. A six-month toxicological study in rats
is comparable to an unlimited treatment time in humans.
Key References:
- Dog TL, Powell KL, Weisman SM. Critical evaluation of the safety
of Cimicifuga racemosa in menopause symptom relief. Menopause
2003;10(4):299-313.
- Mahady GB. Is black cohosh estrogenic? Nutr Rev. 2003 May;61(5
Pt 1):183-6.
- Borrelli F, Izzo AA, Ernst E. Pharmacological effects of Cimicifuga
racemosa. Life Sci. 2003;73(10):1215-29.
Michael T. Murray, N.D., is widely regarded as one of world's leading authorities on natural medicine. A prolific author, Dr. Murray has written over 20 books on health and nutrition including the best-selling Encyclopedia of Natural Medicine and his latest book The Encyclopedia of Healing Foods. Dr. Murray is also Director of Product Development and Education for Natural Factors one of the leading manufacturers of natural products.
Vitamins, Minerals, and Specialty Supplements
encryption technology as verified by Comodo SSL™.
