Herbal medicine is popular. Consumers seem to be attracted by the notion that they are natural – and if it’s natural, it must be safe!!! But do we really know what is in the product that we might be buying? A recently published analytical study aimed to investigate herbal product integrity and authenticity with the goal of protecting consumers from health risks associated with product substitution and contamination.

The researchers used DNA barcoding to conduct a blind test of the authenticity for (i) 44 herbal   products representing 12 companies and 30 different species of herbs, and (ii) 50 leaf samples collected from 42 herbal species. They also assembled the first   standard reference material (SRM) herbal barcode library from 100 herbal species of   known provenance that were used to identify the unknown herbal products and leaf samples.

DNA barcodes from 91% of the herbal products and all leaf samples could be recovered. 59% of the products tested contained DNA barcodes from plant species not listed on the labels. 48% of the products could be authenticated but one-third of these also contained contaminants and or fillers not listed on the label. Product substitution occurred in 30 of the 44 products tested and only 2 of the 12 companies sold products without any substitution, contamination or fillers. Some of the contaminants we found pose serious health risks to consumers.

Based on these findings, the authors drew the following conclusions: Most of the herbal products tested were of poor quality, including considerable product substitution, contamination and use of fillers. These activities dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them. We suggest that the herbal industry should embrace DNA barcoding for authenticating herbal products through testing of raw materials used in manufacturing products. The use of an SRM DNA herbal barcode library for testing bulk materials could provide a method for ‘best practices’ in the manufacturing of herbal products. This would provide consumers with safe, high quality herbal products.

These findings are fairly alarming. I have previously blogged about the fact that herbal products are far to often adulterated or contaminated. Now it seems that we have to add to this list of dangers the substitution of the herbal ingredient with a presumably less expensive but potentially toxic herb that should not legally be there at all.

4 Responses to Herbal supplements: do we really know what is in them?

  • What an amazingly depressing study. I followed through your link and read the whole study as a free PDF here:
    Only 2 of the 12 companies whose products were tested did not have substitutions or fillers not disclosed on the labels. All the products were single herb products (capsules/tablets) available in both Canada and the USA. This should mean they were from larger companies who have grown into an international market. It is stunning that these were all single herb capsules, not formulas or mixes (this rules out most Traditional Chinese Medicine products, which are almost always formulas of multiple herbs). One would assume that a product made of a single plant would be more likely to have the correct species than a product of 10 species having all of the correct species. But they found that less than half of them were the right species, and even then, many had undisclosed fillers such as wheat and rice. The conclusion is clear: Herbal supplement consumers are more likely to be taking a product with the wrong species or undisclosed fillers than a product with an accurate match between what’s on the label and what’s in the bottle. This is *now* in 2013, not before the Aristolochic Acid substitution disaster which rightfully rocked the TCM world.
    I thought the Good Manufacturing Practice (GMP) requirements to independently verify the species/ingredient was strict, and it clearly is more expensive to produce a supplement if one can’t just accept the Certificate of Analysis from the supplier as factual. This study suggests that many, many supplements are not being made to minimum requirements of the GMP. Once again, the FDA (in the USA) is far from being engaged in a successful conspiracy to destroy the supplement world, but is not even able to enforce the sensible rules requiring verification of ingredients.
    A similar DNA was done on TCM medicines last year, with similarly scary findings. Great quotes from Dr. Ernst in this article at Nature:

    • thank you; I had completely forgotten that. here is my quote from last year: “Screening might be a way forward,” says Ernst. “It would be surprising if, among these thousands of ingredients, there were not a few that have the potential to do more good than harm. However, my impression is that we are a very long way from instilling proper science into this area such that patients are not at risk of either direct harm or the indirect harm of treating serious conditions with useless supplements.”

  • Can’t Trading Standards departments get involved in this sort of thing instead of spending taxpayers’ money on supporting the likes of Disney and large footabll clubs who get anmoyed when others make replica shirts at lower prices?

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