Black Cohash: What Does it Really Tell Us?

 

Published October 2, 2004 in the North Island Weekender

As this is Breast Cancer Awareness Month I wanted to write about a very popular herb, Black Cohash and its safety for women with breast cancer or with a history of it. Many patients ask about the safety of herbs in general as they have heard this and that story on the TV or radio. I tell them that 19 years ago when I first started practicing, the medical professions’ general response to a patient seeing a Naturopathic Physician was: “It is a waste of your money, the treatments are ineffective, but it isn’t going to hurt you.” Now the response from the pharmaceutical companies and the medical system is: “Herbs can be not only harmful they can kill you!” They fail to make clear that the proper use of prescription medications in North America within medical institutions is the fourth leading cause of death due to adverse drug reactions (after cardiovascular disease, cancer and smoking) and that does not account for medications taken at home leading to adverse drug reaction leading to death. Deaths from herbs make up .0001% of all deaths. “First Do No Harm” is part of the Hippocratic Oath.

Kerry Bone wrote a recent article on Black Cohash that I would like to summarize for you. He is a very well known master herbalist with an industrial chemistry background. He has been practicing for 19 years and has written many texts and has developed a Masters Degree Programme in clinical herbal medicine. “Principles and Practice of Phytotherapy” has sold more than 14,000 copies worldwide. He lives in Australia.

Back in July 2003, Dr. Davis et al presented at the American Association for Cancer Research held in Washington DC. The media release launched soon after that stated that black cohash may not be a safe alternative for women with breast cancer. Many women diagnosed with breast cancer use the herb as an alternative to hormone replacement therapy (HRT) to control hot flushes primarily. Publication by press release is a growing trend in scientific circles which does not reflect well on the scientists who indulge in such practices. This study has yet to be published in a journal!

Test tube studies have little relevance to oral uses of herbs as many phytochemicals in plants never reach the bloodstream and hence have no chance of reaching the cells which have been exposed to them in the test tube research. The issue of bioavailability of phytochemicals is often overlooked  by many scientist because it is not something they encounter in their conventional medical research. The drug being tested has established bioavailability and, if it does not then it will be administered by injection. In most parts of the world, herbs are not given by injection. Phytochemicals in herbs have not been designed with human bioavailability in mind. Some are absorbed, but many are too large and water loving to cross the intestinal barrier, and others are broken down by stomach acid or bowel flora to form new compounds and so will deliver effects which cannot be anticipated in test tube research on crude extracts. The key constituents of black cohash are saponins and these large water loving molecules will have poor bioavailability so that the powerful effects seen in the test tube are NOT found in the body (in this case the bodies of mice).

In this Davis et al research  the two herbs used were only active at dilutions of 1:500 and 1:1000, at 1:5000 they were inactive. A normal dosage of these herbs would be 1:10,000 well below the levels which were active in the study.

One of the fundamental principles of research investigation is that of repeatability, where the same experiment must be shown to give the same results in a different laboratory. This has not been done as of yet.

The experimental conditions were highly artificial where mice (programmed to get  cancers easier) were fed black cohash for 12 months which is the equivalent of women taking it continuously for 30 years. 

The next question is the source of the black cohash extracts used in the Davis et al study. The details of the phytochemical content are not yet available but this may be addressed if the study is ever actually published in a journal.

Using mouse models to assess the safety of treatment which is already widely used in the community is questionable. Surely the best way to assess any risks associated with black cohash would be to study the health of women already taking it, the same approach used with HRT.  

With the demise of HRT there is increased interest in the use of herbal treatments and it is often assumed that such treatments are estrogenic in nature. Their effects could be much more subtle than that. Recent investigations fail to find estrogenic activity in black cohash. In another recent study there was found strong evidence regarding the safety of black cohash extracts in humans which has been used for the past several hundreds of years.

The bottom line for Dr. Davis et al research is that it is only transgenic (genetically engineered) mice that need to be cautious about consuming black cohash.            

The next time a news item instills fear about taking a herb remember the key points in this article. Look for the research, was it even published, what form of the herb was used, in what doses was it given, how much of the herb is actually being absorbed, was it done in the test tube or in humans and has it been reproduced. You can also call your local naturopathic physician to help clarify these issues for you.

After digging through the study it can often be found that there were great flaws in the research and you should be much more afraid to take some of the common over the counter drugs used to treat pain, which are very liver toxic, than most of the herbs on the market today.

Dr. Pincott has been practicing naturopathic medicine since 1985 and is currently practicing in Campbell River. She can be reached at (250) 286-3655 or www.DrPincott.com