The rapid growth of the herbal products industry in the past few years has been nothing short of explosive. But consumers of herbal and dietary supplements currently have no standard, reliable way to compare these products for dosage, source, quality and purity. And as the popularity of these products continues to skyrocket, this will become an ever-increasing problem.
In a keynote address to a recent gathering of experts in herbal medicine sponsored by the University of North Carolina and Duke University, Dr. Varro Tyler of Purdue University noted that herbal products are already used by at least one-third of U.S. adults and have an annual retail market value of about $4 billion. Yet, he said, the safety, efficacy, and quality of many of these products remains unproven.
He particularly criticized the 1994 Dietary Supplement Health and Education Act, under which the Food and Drug Administration regulates medicinal herbs as dietary supplements rather than as drugs, which are subject to much more stringent standards. Herbs are potent medicines, he said, and if used incorrectly they can be far from harmless.
Standardizing an Industry
In a landmark article, researchers June McDermott and Thomas Motyka highlighted a number of areas in which the safety and effectiveness of herbal products can go awry, and they recommended sweeping, industry-wide changes to address these problems:
- Authenticity - Plants should be accurately identified using standardized laboratory methods. They should be referred to by their botanical Latin name rather than their common name (which can sometimes be applied to more than one plant within a species). Also, the specific part of the plant that is being used in the preparation should be identified (e.g., flower, leaf, seeds, bark, root, etc.). Different parts of the plant contain different chemicals that can have dramatically different actions.
(Regarding the latter point, traditional medicine systems support the use of the whole plant or plant part and not just the extract of isolated chemicals. It is thought that there is a synergy among the many plant constituents and that the true benefit depends on their combined effects.)
- Growing Conditions - Growing conditions such as soil, altitude and climate can markedly influence the final effectiveness of herbal products. Although not much can be done to specify where products are grown, at least the optimal storage conditions for each botanical product should be standardized, including temperature, light and humidity. Also, herbal products should be grown without exposure to pesticides, herbicides, toxic metals and other contaminants.
- Manufacturing Conditions - Plant extracts are dependent on the solvent used in the extraction process as well as the extraction time and temperature. Therefore, these should be identified. Expiration dating should be mandatory and lot numbers and test results should be logged. The manufacturer should also guarantee the specific quantity of active constituents in the final product.
Industry Responses
McDermott and Motyka point out three new industry initiatives that should go a long way toward standardizing the safety and effectiveness of herbal products on the market.The National Nutritional Foods Association, a trade association for the dietary supplement industry, has established a "Good Manufacturing Practices" certification program that will require third-party inspections of the manufacturing facilities to determine whether certain standards are being met. The manufacturer will then be allowed to use a seal on its product labels ensuring the consumer of a quality product. The program will be phased in by the year 2002.
In a similar vein, a privately held company, ConsumerLab.com, has begun a program for the independent testing of herbal products and dietary supplements. Products passing their testing procedures can then carry their certification seal on the label.
Finally, the Institute for Nutraceutical Advancement, which provides analytical services to the natural products industry, is developing a "Methods Validation Program" designed to standardize methods for testing compounds in herbal products. They have currently validated and published methods related to six botanical species, with more being added each year.
A Patient's Responsibility
Even in a best-case scenario, however, it will be years before a meaningful, industry-wide system is implemented that will guarantee the safety and effectiveness of all herbal products on the market. And even then, herbal supplements will still not undergo the stringent review and approval procedures that the Food and Drug Administration applies to medicinal drugs.
Therefore, consumers themselves must take the initiative to ensure the quality and safety of what they are purchasing. Talk to your pharmacist, read the labels, and most importantly of all, let your physician know that you are taking herbal supplements. While most herbal products are safe if taken in the appropriate doses, they can skew the results of certain diagnostic tests and possibly interact with other medicines being taken.
In a study presented at the annual meeting of the American Academy of Family Physicians, Dr. Margaret Planta reported that 60 percent of the patients she interviewed at a low-income county health clinic reported using herbal remedies or dietary supplements. But more than half (53 percent) said they had not informed their physician. Furthermore, nearly 20 percent of the patients who reported using such product said that they had no intention of telling their physician about their use of the products.
In a related study, Dr. John Metz of the University of Pennsylvania reported at a recent meeting of the American Society of Clinical Oncology that cancer patients tend to divulge their use of alternative therapies only when directly questioned by their physician. After interviewing 196 cancer patients, just 13 (7 percent) said they were using an alternative or unconventional therapy. Yet, more than a third of the patients (34 percent) admitted using vitamins, herbal supplements, shark cartilage, guided imagery or meditation when asked directly about these therapies.
A growing number of research studies are now underway which are testing the safety and effectiveness of at least the most popular herbal products. For example, four herbal products-aloe vera, ginseng, kava kava, and milk thistle-have been recommended by the National Cancer Institute for substantially increased testing because of their widespread use by the public. NCI also cited indole-3-carbinol, a substance found in cruciferous vegetables such as broccoli, as a compound requiring additional study.
But many more herbal products must be subjected to similar scrutiny. And definitive results from these and other studies are still years away. Therefore, in the interim, the old adage still applies-buyer beware.
SOURCES:
"Assessing the Quality of Botanical Preparations," McDermott JH, Motyka TM, Medscape Pharmacology, 2000
National Cancer Institute (www.nci.nih.gov)
Pediatric News, 2000:34
Clinical Psychiatry News, 1999; 27(11):40
American Society of Clinical Oncology (www.asco.org)
American Academy of Family Physicians (www.aafp.org)
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