Studies of Herbal Medicine Found Inadequate
Little information about efficacy, safety, quality
THURSDAY, Dec. 19, 2002 (HealthDayNews) -- In a wide-ranging critique of herbal medicines, a Dutch scientist reports that a lack of regulation and scientifically rigorous research damages the safety and efficacy of the alternative remedies that are taking up increasing space in the nation's medicine cabinets.
Faced with the popularity of herbal remedies like St. John's wort, ginkgo and saw palmetto, it is incumbent upon doctors to take a more active role in advising patients about the non-regulated substances, says pharmacist Peter A.G.M. DeSmet of the Scientific Institute Dutch Pharmacists in The Hague.
"It is imperative to ask patients whether they are taking herbal products, particularly when they present with an unexplained health problem. Clinicians must be informed about the potential effects of herbal preparations and must be able to discuss this subject in a non-judgmental way," DeSmet writes in today's issue of The New England Journal of Medicine.
His review article was accompanied by two essays in the journal calling for more research and regulation of the exploding herbal medicine market. About 10 percent of Americans now take them, according to the U.S. Centers for Disease Control and Prevention.
"The sale of herbal medicines ought to be based on reasonable evidence that they do something and that they're safe, but the information people now have to guide them ranges from misleading to wrong," says Dr. Donald Marcus, an immunologist at Texas' Baylor College of Medicine and author of one of the essays.
Other serious problems, he says, are that many herbal products contain undisclosed and possibly dangerous prescription or over-the-counter drugs, and that the labels on herbal medicines offer little information about possible adverse effects.
"The adulteration issue is a very real one," he says, citing as an example a 1998 California Department of Health report that found that 32 percent of Asian patent medicines sold in the state contained undeclared drugs such as ephedrine, lead, mercury and arsenic.
"Also, accurate labeling including real warnings should be on herbal products," he says.
Ginkgo is a very popular herbal product that is supposed to improve memory. However, he says, the herb can affect blood platelets and can be dangerous for people who are already taking anticoagulants to thin their blood. Yet the labeling on most ginkgo pill bottles recommends only that people check with their doctors.
While prescription drugs must undergo rigorous testing before being approved for sale by the U.S. Food and Drug Administration (FDA), herbal products must only conform to the much less onerous 1994 Dietary Supplement and Health Education Act, which defines herbs as dietary supplements. As such, while holding herbal manufacturers responsible for the truthfulness of the claims they make about their product, the law requires no evidence to back up those claims.
For the past five years, the FDA has been working with the herbal industry to set up more stringent, mandatory manufacturing guidelines for herbal products, the authors report, but the guidelines are not yet completed.
Marcus, in his essay, blames the delay on the botanical industry, claiming that it has "consistently blocked" such a proposal. An industry spokesman denies the charge.
"It is untrue," says John Hathcock, vice president for nutrition and regulatory science for the Council for Responsible Nutrition, stating it is in the interests of reputable herbal medicine manufacturers to have recognized quality standards.
"The industry has asked for regulations for the past five years, especially in the area of good manufacturing practices," he says, and he commends the Netherlands study as being "pretty well-balanced and the reviews of the studies pretty much on target."
In the Netherlands study, DeSmet discusses the problems of measuring the quality and efficacy of herbal medicines as well as insuring their safety in the unregulated marketplace. He then reviews several dozen studies of four popular herbs: ginkgo biloba, used to treat dementia; hawthorn, recommended in cases of heart failure; saw palmetto, used to treat swelling in the prostate; and St. John's wort, recommended for depression.
He reports that a number of the studies reported scientifically significant improvements in symptoms for these illnesses, but criticizes the methodology of many of the studies as having too few participants, being too short in duration, failing to use standardized symptom scores to rate results, or reporting only positive results.
In discussing the data used to support the use the St. John's wort to treat mild or moderate depression, for instance, DeSmet points to one review that stated the rates of response to St. John's wort were 23 percent to 55 percent higher than response rates to a placebo. However, the authors write, the review identified only one of the randomized, controlled trials used as a basis for the conclusion as without methodological flaws, and "even that trial has raised some questions."
Marcus, who teaches medical students about alternative medicine by having acupuncturists, herbal medicine specialists and homeopathic doctors speak in his classes, is personally skeptical about the benefits of herbal medicines. However, he believes strongly that doctors need to be informed enough about herbal medicines and open enough so that their patients will discuss the subject with them.
"I think the evidence is very clear that using herbs has considerable potential danger and very little upside," he says, especially when FDA-approved prescription drugs are available to treat the same illnesses.
"But doctors do need to inform themselves about popular therapies so they can provide help to patients. People aren't asking their doctors about herbal medicines. They're just taking them," he says, yet it is their doctors who, in the face of poor regulation, are the ones who can help patients avoid the pitfalls of poor combinations of drugs and the dangers of certain herbal products.
What To Do
The American Academy of Family Physicians and the National Institutes of Health have helpful fact sheets on what you should know about the risks of mixing herbal medications with certain medical conditions. An explanation of the different kinds of alternative medicine can be found at Alternative Medicine Foundation Inc.