Are Consumers ‘Inappropriately’ Using Herbs?

Study finds that adults are not using herbs in accordance with evidence-based indications.

By
Marian Zboraj
Associate Editor

The May issue of the peer-reviewed journal Mayo Clinic Proceedings published an article titled “Use of Herbs Among Adults Based on Evidence-Based Indications: Findings From the National Health Interview Survey,” in which it examined the extent to which U.S. adults use herbal supplements to treat a specific health condition in accordance with evidence-based indications. The Natural Standard database was used to formulate evidence-based standards for herb use. These standards were applied to the National Health Interview Survey (NHIS) data to identify groups of people who used herbs “appropriately” and “inappropriately,” using a multivariable logistic regression model. According to researchers, of the 30,617 adults surveyed, 5787 (nearly 19%) consumed herbs in the past 12 months. Of those, 3315 (57%) used herbs to treat a specific health condition, but researches found that roughly two-thirds of adults using commonly consumed herbs (except echinacea) did not do so in accordance with evidence-based indications.

The study suggests that consumers may not fully understand the intended scientific use of particular herbal products and therefore are inappropriately using them. Mark Blumenthal, founder and executive director of the American Botanical Council (ABC), Austin, TX, doesn’t discredit the study, but he points out that consumers often use herbs based on traditional use, not on modern scientific information, which doesn’t mean the herbs are being “misused” as interpreted by various mainstream media outlets.

The goals of the recent study were to examine the indications that consumers report for taking individual herbs and to determine whether these are consonant with available evidence, but Steven Dentali, PhD, vice president, Scientific & Technical Affairs, American Herbal Products Association (AHPA), Silver Spring, MD, notes that the article makes no mention of the contradicting practice of doctors recommending products’ off label use. “Every women taking an non-hormonal product for menopause, which doctors constantly prescribe, is taking a product where the science doesn’t support that use,” he said. “The article basically indicates that consumers don’t use herbs based on science, but very little of medicine today is evidence-based.”

From traditional Native American medicine to ancient Chinese remedies, it’s true that the current knowledge of numerous beneficial plants and herbs originated from various historic cultures. However, some argue that many of the alternative uses for plants still have not been scientifically studied, or if they have, the studies have been very limited. According to Mr. Blumenthal, if research has refuted a traditional use of an herb, a flawed study may be the culprit. “For example, using a poor quality herb, not using proper dosage, not choosing a proper end point, using narrow criteria for inclusion of the participants, or not including the appropriate population to be tested—there are many reasons why studies fail,” he said. “And it doesn’t necessarily dismiss the potential use or benefit of a particular herb.”

Dr. Dentali agrees that much of the studies being conducted on herbs have not been well designed and to claim herbs do not work based on such research is unfair. Proving that the quality of evidence conducted in the U.S. is sorely lacking, he states that approximately 95% of investigators that apply for grants from the federal government to study conventional alternative medicine have no prior experience in the field.

This further complicates matters because even though herbs have been used for centuries, science has yet to catch up with all of the potential benefits. Consumers could be effectively using herbs in a traditional sense, but because these ways have yet to be scientifically validated, their use is considered inappropriate. Bottom line according to Dr. Dentali is lack of proof of efficacy is not proof of lack of efficacy.

“We are still in the relative infancy of conducting clinical trials to test historical and traditional uses of herbs,” said Mr. Blumenthal. “Clinical trials based on certain herbs are often very narrow in the scope of the potential use of that herb, at least based on historical use. Consumers using herbs in ways that are not consistent with existing levels of published evidence does not constitute misuse. It only means that some of the science may have not yet have caught up with the traditional usage. We have to understand that unproven does not mean disproven.”

Research is of course vital to the industry, but Dr. Dentali feels science is also more than just double-blind placebo-controlled studies. “Science is an organized body of knowledge,” he said. “We have an organized body of knowledge for herbs that is centuries old. Not fitting the new model of published evidence-based indications has no relevance as to whether it works or not. Herbs have been used effectively long before these trials were even created.” Dr. Dentali suggests that if evidence-based indications are going to be utilized in the field then it should be established on appropriate science that concentrates on the effects based on traditional uses, rather than stacking herbs up against evidence-based drugs—which they were never intended to do.”