“Shoddy” herbal safety study slammed for bias

A study that found 75% of herbal products on sale in the UK were not adequately labelled with safety information has been criticised for mischaracterising the majority of products it assessed like ginseng, ginkgo and St John's wort.

The Alliance for Natural Health (ANH) said 48 of the 68 products in the study published in the journal BMC Medicine were labelled as food supplements, governed by the EU Food Supplements Directive, and therefore did not require the kind of safety data the researchers concluded was lacking.

They therefore disputed the study findings that matters were improving under the Traditional Herbal Medicinal Products Directive (THMPD).

“Herbal products sold as food supplements, by contrast, are intended for healthy populations; as a result, indicating the product's risks, for example, to diabetics or other diseased populations might be sufficient for a regulator to deem the product as medicinal under the broad scope of EU medicinal law,” the group said.

“It is what might be described as a ‘Catch 22’ situation.”

The group added: “It can be seen, therefore, that many of the products criticised by the study authors for not including patient safety information are not legally obliged to do so.

It went on to criticise the study, led by David K Raynor from the University of Leeds, for misinterpreting US National Center for Complementary and Alternative Medicine (NCCAM) monographs in regard to dosage and usage, and ignoring Community Herbal Monographs published by the European Medicines Agency.

Conflicts of Interest

The ANH also said there were undeclared conflicts of interest among the study authors.

“The main author, David K Raynor, from the School of Healthcare, University of Leeds, is a director of Luto Research. One of the co-authors, Peter Knapp, was a co-founder of Luto, and Alison Blenkinsopp, who reviewed the manuscript, is a non-executive director of Luto. Luto Research "specialises in improving patient communication [by working] to enhance the clarity of information created for patients": in other words, they develop the type of patient information leaflets that this study finds are so sorely needed in OTC herbal products."

“So by giving the paper its particular spin, they give themselves a high chance of earning lucrative consultancy income from a new industry. Several of the authors have worked together in the past to evaluate patient information in the pharmaceutical sector – now it appears they have been led to new, fertile pastures.”

The group concluded: "...without having categorised the products appropriately, by looking at only five different kinds of single-herb product in the UK, and by ignoring the dosage of herbal active ingredients within the products, we believe that the study is not worth the paper it is printed on.”

From the US, Cara Welch, PhD, the vice president of scientific and regulatory affairs at the Natural Products Association added: “The dietary supplement industry is committed to providing high-quality products for consumers to lead healthful lives. There are a number of labeling requirements for dietary supplements manufactured and sold in the US; in addition, many manufacturers go the extra step to include information about the safe use of their products.”

“The NPA, along with our independent natural product retail store owners, urge consumers to discuss their supplement use with their physician to ensure the consumer is getting the best overall care and to avoid any interactions.”

Mark Blumenthal, the founder and executive director of the American Botanical Council, said the literature did not back up some of the contraindications cited in the research.

“To my knowledge there's no credible evidence that Asian ginseng be contraindicated in type-2 diabetes – in fact clinical studies show that it and/or American ginseng might be useful in helping to modulate blood glucose levels – and there's certainly no credible evidence that any form of Echinacea cause allergenic reactions.”

The full ANH response can be found here.