A couple years ago,
a study of herbs and other natural remedies for menopause got a lot of press. Particularly of note were its assertions that black cohosh is the only herb shown to help in menopause.
We could incorrectly assume then that no herbs help for menopause. However, there are some problems with that conclusion. Let’s take a look at them:
1. Most herbs have not been subjected to RCT’s (Randomized Controlled Trials, medical science’s most advanced study design).
2. RCT’s are not the only kind of study that provides reliable information.
3. Herbs are hardly ever prescribed alone. Research should be conducted on time-tested herbal formulas for menopause – not single herbs.
4. American researchers tend to ignore or discount research done outside the U.S.
5. Researchers’ own biases affect their conclusions… no study is perfect. Researchers may have little trouble finding reasons to throw out a study whose conclusions threaten their beliefs.
Ok, then…
1. Which herbs have been subjected to RCT’s?
A quick search of MedLine for “herb randomized controlled trial” yields only 13 results for 11 herbs and herb formulas (note that searching for just herbs alone yields more than 2300 studies):
St John’s Wort, Black Cohosh
Bing gan tang, Yi zhu tang, Yi Er Gan Tang (Hep C)
Phyllanthus, ‘Jianpi Wenshen recipe’, Fuzheng Jiedu Tang (Hep B)
Polyporus umbellatus polysaccharide
Echinacea (Common cold)
Ginger (Nausea)
‘AM’ a Ugandan herb remedy (Malaria)
I know this is not the full list of well-studied herbs. The groundbreaking 1998 Journal of the American Medical Association issue on alternative medicine included the first RCT faithful to the principles of chinese herbal medicine, a study of herbs for IBS.
In the November 2002 review of menopause treatments, only 10 of the 29 studies (RCT’s) they reviewed studied herbs. Of those, only two – black cohosh (sheng ma) and dang gui – are chinese herbs. There are many chinese herbs and herbal formulas for menopause that have not been studied in RCT’s.
2. RCT’s aren’t the only kind of study.
Without a doubt, they are the best, the gold standard… they eliminate the placebo effect as much as possible, etc. They’re good. But most herbs haven’t had their RCT day in the sun. Why not? Because it costs a lot of money!
Drug companies spend hundreds of thousands of dollars on each drug to prove its safety (not necessarily its effectiveness) in RCT’s. No single company has a motivation to study an herb which they cannot patent, own, and have the exclusive right to sell. They may take the course of isolating one part of an herb and patenting that, but then we’ve taken the herb out of its traditional framework. Applying it like a drug puts it in the biomedical treatment framework- the same one that assumes side effects are unavoidable. We’d like to avoid that!
There are plenty of other kinds of studies- from smaller scale clinical retrospectives (analyzing the data from treatment records) to in-vitro (in a glass tube) lab studies of herbs’ effects on micro-organisms. In-vitro studies can show how a substance works, but don’t tell us how it works in humans.
A search of MedLine for “Chinese Herb” yields 879 results. We get everything from the effect of herbs on rats in space (yes, really) to drug-herb interactions. And we find a lot of studies from outside the U.S. I don’t have time right now to survey all 626 – sorry!
But the point is that there are a lot of studies out there that tell us positive things about herbs even though they haven’t yet been awarded adequate funding for an RCT.
3. Herbs are hardly ever prescribed alone. Research should be conducted on time-tested herbal formulas for menopause – not just single herbs.
Most people know little to nothing about the most comprehensive and effective traditional system of herbal prescription – Chinese Herbal Medicine.
Clinical experience and research studies have shown that herbs work better in groups (formulas) than alone. Just as certain drug combinations have positive or negative effects, certain combinations of herbs have special additive functions or may need to be avoided.
The first systematic herbal text was written in 200AD, the Shang Han Lun (Cold Damage Classic). For at least 1800 years, chinese herbs have been prescribed primarily in formulas – groups of 4-12 herbs.
New research on chinese herbs should verify, refine, and build on the last 1800 years. The idea to research single herbs comes from the pharmaceutical drug paradigm, not the tradition to which chinese herbs belong. It makes sense that since most American researchers are biomedical that they would use a biomedical approach… but it’s still wrong.
4. American researchers tend to ignore or discount research done outside the U.S.
I wasn’t able to find anything to back this up, so I’ll just say that it seems as if American researchers don’t acknowledge research from other countries. Or perhaps they simply are more skeptical of it? In any case, I notice that many of the topics I investigate (alternative and complementary treatments) are studied in Europe, but not in the U.S. I admit I don’t have all the info on the general level of quality of studies from different countries, or how much and why American researchers disregard such studies.
5. Researchers’ own biases affect their conclusions. No study is perfect. Researchers can easily find a reasons to be skeptical about any study that opposes their own beliefs.
This is backed up by a meta-study I found… the psychology researchers found that those who reviewed studies were more likely to criticize its methodology if its conclusions disagreed with their bias, and more likely to approve of its methodology if its conclusions agreed with their bias.
There is no such thing as a perfect study. Good research tries to keep problems affecting the results and interpretation at a minimum, but imperfections are unavoidable. That means that if someone doesn’t like the results of your study, they can find a reason to discredit the study.
This reminds me of the joke: “97% of all statistics are false.” This implies, of course, that it could itself be false. Statistics, like anything else, can be deceiving. Inaccuracies of commission or omission (conscious or unconscious) can “spin” the truth toward the reader’s bias.
Traditional Chinese Medicine (Herbs and Acupuncture) for Menopause
The review of RCT’s on herbs for menopause shows that many herbs still need to be investigated. However, RCT’s are not the only reliable proof that medicines are effective and safe.
At least 1000 years of tradition indicate that chinese herbal medicine helps balance women in menopause. Acupuncture has been used for somewhere between 2,000-30,000 years.
Acupuncture and herbs for menopause help alleviate many symptoms; most commonly responsive are hot flashes, depression, and vaginal dryness. Salivary hormone tests in clinical settings often show changes in testosterone and progesterone.
Another interesting point about the November 2002 study is that neither black cohosh nor dang gui are used alone in chinese herbal remedies for menopause. Black Cohosh can cause headaches and dizziness, but might be safely used in an herbal formula for menopause. Dang gui is similar- it is a warming herb, so by itself it could even increase the heat in hot flashes!
The moral of the story: See a chinese medical practitioner and use formulas, not single herbs.
Menopause Herbs Don’t Work?
by Brian Benjamin Carter
