The many faces of herbal adulteration

Bilberry extract sometimes sees substitution with amaranth, a purple food dye
Bilberry extract sometimes sees substitution with amaranth, a purple food dye
The global natural products industry is beholden to vast quality control challenges, which are in turn amplified when it comes to herbal ingredients, given the quality management minefield this segment presents. 

Those involved in adulteration devote substantial energy and resources attempting to thwart the detection techniques that are known to be used by quality control personnel. Generally speaking, the adulterants that are not routinely tested for can set the traps for organisations in our space.

As a catch-all term, adulteration can be considered to cascade down to substitution, fortification and depletion, as well as unintended instances of adulteration that generally involve mistaken identity.

As its name implies, substitution​ occurs when a herb is simply replaced by another herb or substance. 

A number of classic cases exist for this method of duping the consumer, for example amaranth, a purple food dye also known in many countries by its food additive code E123, can be a substituent in materials proffered as bilberry extract. 

Amaranth has been banned in the US since the 1970s and is heavily restricted in most other markets, bringing related safety concerns into play for this method of substitution. 

Techniques to detect substitution of bilberry with amaranth have been available for a while now, but like all good detection techniques, they’re only as valuable as our readiness and willingness to use them. 

Due to its high commercial value, bilberry has seen many and varied methods for supplanting with low-cost substitutes. You can read more about this along with detection methods in a 2014 paper on Bilberry adulteration detection, published in the journal Fitoterapia​.

The next adulteration category, fortification​, involves “topping up” what is often a key constituent and/or quality marker in an herbal ingredient. The intended purpose of this is to mislead quality control personnel into believing a herb naturally contains more of a key component than it actually does. 

One extreme example of fortification was the baby formula scandal that rocked China in 2008 and resulted in 54,000 hospitalised infants. Melamine was added to artificially “boost” the protein content of the formula formula, thereby parading it as a higher quality product than it was in reality. 

In the herbal context, a common example of herbal fortification is the addition of synthetic caffeine to guarana, or synthetic ascorbic acid to acerola. Both instances present little in the way of safety risk as the synthetic varieties of these components are used widely in food preparations. 

The issue therefore is with the ingredient user being given the impression that the quality standard of the product they receive is higher than it actually is. It also proves challenging for those ingredient companies aiming to do the right thing by their customers, who are forced to wrangle with low-cost competition operating on an entirely different quality plane. 

Should the provider of the fortified ingredient be forced to declare when these synthetic additives are used? Why would said ingredient provider be reluctant to disclose this information?

The practice of herbal depletion​ involves the removal of key therapeutic active constituents with the sale of the remaining “by-product” as a herbal extract ingredient. 

One stark example of such a practice is with milk thistle extract. The components silybin A and B are to some extent removed from the crude material and go off in a different direction for pharmaceutical use in the treatment of liver disease. 

The leftover by-product is then supplied at a very low cost to the supplements market as “silymarin extract”. Historically, analytical procedures for quantitation of key milk thistle constituents would not detect when the product was silybin-depleted. It’s comforting to know at least in this case, analytical techniques are becoming more available to help identify when the herbal ingredient on sale is actually just a cheap by-product.

Then after all is said and done, we have good old fashioned adulteration​. This generally consists of the addition of other substances to trick the user into believing they’ve received an authentic, 100% adulterant-free product. 

The examples of straightforward adulteration are numerous, and unfortunately not that straightforward to detect. Present examples under review by the industry include the addition of quercetin to ginkgo extracts, or the more sophisticated addition of Sophora japonica​ which has succeeded in toppling some of the earlier adulteration detection methods. 

Another prevalent case is the inclusion of peanut skin in grapeseed extracts. An example of adulteration at its best (read: worst), it is difficult to detect and provides for a low-cost alternative, while having substantially questionable safety characteristics.

The challenge for the industry in continuing the battle against adulteration practices might seem insurmountable. To date, we have been forced to deal with each technique on a case-by-case basis, developing detection methods that address the means of specific adulteration head-on, but a blanket system for eliminating adulteration remains as elusive as ever. 

Ingredient users must demand quality, but with so much price competition on the global natural products stage, the difficulty prevails in delivering a high-quality, authentic herbal ingredient at a price the consumer is willing and able to pay.

  • Ryan Gorman is the founder and chief executive of Network Nutrition, which became part of the publicly listed Dutch multinational IMCD in 2013. The company is the recipient of the industry peak body Complementary Medicines Australia (CMA) Quality Raw Material Supplier Award three years running (2012/13/14), making Network Nutrition-IMCD CMA’s most awarded ingredients provider.

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