What clinicians should know about herbals

A literal myriad of products is available in the United States for dietary supplementation. Sometimes called “nutraceuticals,” these naturally occurring chemicals have been mass-produced for the purpose of augmenting or otherwise enhancing normal cellular function. Not only are herbal supplements readily available, they are also hugely popular. As many as 30%-60% of Americans are either currently taking or at some time have taken a nutraceutical. This poses an interesting and challenging problem for clinicians. Because there is little clear scientific data available on the safety and efficacy of many of these products and because many herbs interact with prescription drugs, there is a real potential for serious harm.

So what is the tremendous attraction to these unproven supplements? In the NIH's ongoing Complementary and Alternative Medicine trial, 55% of participants cited the hope of improving health by combining traditional medicine with these therapies; another 50% felt it would be “interesting” to try herbals. Of those participating in the trial, 28% had already failed conventional therapies.1 Simply put, the high rate of herbal-therapy use is the result of an increasing desire on the part of patients to control their own health without having to access the formal health-care system.

Overview of herbal use

The herbal-product industry is one of the fastest growing health industries in the nation, increasing at a rate of 20% per year. In 1997, more than $3 billion was spent on herbals, a figure that was well on its way to topping $5 billion in 2000.2 Even so, herbal therapy in this country is still in its infancy. The Chinese have been masters of alternative therapies for thousands of years. Native Americans had a well-developed knowledge of the use of herbs in medicine, and early pioneers relied heavily on this knowledge. In the mid-19th century, physician John C. Gunn wrote what would become a leading textbook for rural and pioneer doctors, Gunn's Newer Family Physician. In it, Gunn proclaimed, “The Creator has supplied abundant resources, and each tree, herb, and flower possesses some medicinal virtue.” This life-force belief system was prevalent in the day not only culturally but by sheer utilitarian necessity.

More recently, Commission E, Europe's version of the FDA, has methodically studied and categorized more than 700 herbals and published more than 300 monographs on selected products.3 One source estimated that botanical products account for the primary form of health care in nearly 80% of the world.4 Herbal prescriptions are frontline in most German practices, accounting for more than 70% of prescriptions written by health-care providers, and, for the most part, they are reimbursable by insurance.3

Since there are more than 250,000 known species of flowering plants, it is a daunting task to individually study the safety, potential efficacy, and dosage of each root, seed, leaf, and flower. Geographic differences come into play, as do the additive costs of production. It should be noted, however, that an estimated 25% of our current patented pharmaceuticals are at least partially plant-derived.5

Are herbal supplements safe?

As is the case with any substance taken for a medicinal purpose, safety is always the first concern. Unfortunately, many consumers assume that since herbals are “natural” products (not artificially synthesized), they are safe. In truth, there have been very few scientifically conducted trials that meet the FDA's traditional criteria of “randomized and controlled,” let alone expanded toxicology and pharmacokinetic studies.4 So the burden of assessing safety falls to the user. (For the FDA's role in regulating the use of herbal supplements, see sidebar.) As clinicians, whether or not we approve of the use of these products, we must understand the available data so we can assist our patients in making the best choices for their health needs.

The herbal industry itself has given rise to some forms of safety controls. The American Herbal Products Association (AHPA) has developed a safety rating system to try to distinguish the various levels of known risk associated with herbals in the United States.

In order to appropriately work with a patient who is either using herbals or wishes to do so, we first must establish honest communication. Studies have indicated that as many as 30% of patients using supplements do not readily provide this information to their clinician. This may be because patients fear being scolded for using an unproven product. Or more likely, since most consumers believe that herbals are harmless, they see no real need to inform their clinician. But herbals are very much to be chemically reckoned with in the body's metabolism, and clinicians must make the patient aware of the importance of disclosing the use of any herbal product.

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