How to Evaluate the Research on Herbal Medicine for Those With Hepatitis and Liver Disease
Walking through the aisles of a health food store or supermarket, you are likely to see many everyday products—such as green tea, licorice, artichokes, dandelion root, peppers, and turmeric—claiming to be beneficial in the treatment of liver disease. Obviously, one should and must research an herb more thoroughly before taking it with the expectation that it will help the liver. Simply reading the label on a supplement bottle, reading the description in an herbal remedy book, or asking the owner of the health food store if a particular herb will help the liver may not be enough. There are many steps a person can take on her own to determine if the herbal product that she is considering taking is, in fact, effective.
Many libraries, as well as the Internet, have access to medline (an electronic database maintained by the National Library of Medicine), which contains thousands of medical research papers. From MEDLINE you can get copies of original scientific articles cited in magazines, books, or journals. This will provide you with information as to what doses the investigators used and under what conditions they were used. Also, it is advisable to consult the Physicians’ Desk Reference (PDR) for Herbal Medicines. This book provides a wealth of important information on herbs. It provides indications for an herb’s use, including whether the indication is considered controversial; some of the known side effects of the herb; and some possible interactions with other drugs. Anyone contemplating the use of an herbal preparation is urged to purchase this book. Thanks to this book, people now have a good starting place for researching a particular herb or dietary supplement. In addition to the PDR for Herbal Medicines, the Office of Dietary Supplements (ODS) at the National Institutes of Health (NIH) has an up-to-date comprehensive website containing a database of scientific publications related to dietary supplements (see Appendix for website addresses). And, in 1998, the Commission E Monographs was translated into English—The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. This book describes which herbs have been approved or rejected in Germany for medicinal uses, the recommended dosages and uses of approximately 250 specific herbs, the contraindications, possible adverse reactions, and drug interactions that may occur with specific herbs.
As a general rule, there isn’t as much scientific research on herbal remedies as there is on conventional therapies. Much of what does exist is usually based on a small number of test subjects who have taken the herb in question for a short duration. Still, it’s worthwhile finding out exactly what sort of information exists. With the increased interest in herbal products, there are bound to be more and better controlled scientific studies in the future. In fact, randomized controlled trials have begun to be conducted in the United States on the efficacy of certain herbs. Unfortunately, results so far been disappointing. For example, studies on the herb St. John’s Wort, which is commonly used to treat depression, concluded that this herb did not have significant efficacy. Studies done on ginko, an herb purported to improve memory, have concluded that ginko does not provide significant benefits to memory. Studies done on milk thistle (silymarin) see page xx, have concluded that this herb does not provide any benefit to people with the liver disease primary biliary cirrhosis (PBC).
In order to evaluate a research study, a few guidelines must be kept in mind. First and foremost, no single study can be considered to truly prove anything. Find out if the results have been reproduced in other laboratories or by other researchers. Next, try to determine the study’s credibility—has it been published in a well-respected medical journal (such as most of those appearing in the bibliography of this book) or has it only been self-published—as in a book or pamphlet that does not require any type of review. Look closely at the details of any study you are trying to evaluate. Did the investigators actually compare two groups of subjects (a control group and an experimental group) or had they simply performed an observational study, which simply involves looking at what happened to people taking the product in question? If they used a control group, how did they ensure that the two groups were indeed comparable in every way before the study began? Is there a possibility that the control group was actually sicker than the experimental group? What criteria did they use to include people in their study? Have they made sure that there weren’t other disorders or other medications that confounded their results? How long did the study last and what happened after the treatment was stopped?
After examining the methods that were used to conduct the experiment, look at the conclusions. Are they warranted by the evidence? Have the investigators taken into account the placebo effect (an improvement in response to treatment with a placebo, not the substance being tested)? Be particularly wary of research that does not include possible alternative explanations for its findings.
If a person can’t find any useful information from independent sources on the efficacy of the particular herbal remedy in question, then it may be time to ask some tough questions, including: Do I want to be a guinea pig for an untested product? How do I know if the product is safe if I become pregnant? What guarantees do I have that the compound won’t promote cancer, trigger ulcers, or contribute to liver failure? How do I know what dose I should use and how often? If the person still decides to take the compound, she should be sure to tell her doctor, so that the doctor can be on the lookout for any potential side effects or drug interactions.
All contents of this article are Copyright © Melissa Palmer, MD
Melissa Palmer, MD is the author of " Dr. Melissa Palmer's Guide of Hepatitis and Liver Disease". (Published 2004. Penguin Putnam).
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