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How pesticide cocktails can taint ‘natural’ herbs

The safety and purity of traditional medicines are a growing concern in a world of unscrupulous production

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By Narda Robinson, DO, DVM

“Natural” plant medicines can both help and harm, but the more we learn about how medicinal plants are cultivated, harvested, stored and sold, especially in China, the more we realize the need for heightened scrutiny and regulatory enforcement.

Uncertainties about safety from seedling to shipment raise the central question: “Are herbs ultimately helping or harming?”

Some argue that traditional remedies must be safe considering how many people and animals depend on them for their primary health care needs. Indeed, most of the world’s population relies on herbal and traditional remedies (about 75 percent, according to World Health Organization estimates); it follows that the vast majority of people living in developing countries also depend on indigenous agents for their animals’ health.

Thus, the safety and purity of these medicines becomes a One Health issue with heightened importance, given the rising reports of unscrupulous production.

The lack of obligatory adverse event reporting along with the laxity of manufacturing guidelines and perpetual unwillingness of consumers to report problems all contribute to unknowns regarding the true public health impact. Moreover, the wanton exposure of medicinal plants to pesticides and heavy metals poses additional risks not present decades ago.

In contrast to synthesized pharmaceuticals, herbal medicines take up pesticides, herbicides, heavy metals and more along with the water and nutrients they derive from the ground. Instances have surfaced where common spices such as ginger, cinnamon and black pepper show high levels of lead, depending on where and how they are grown.

Heavy metals contaminate medicinal plants most frequently in industrial areas where factories’ effluents pack high amounts of damaging pollutants.

Metal pollution affects how plants grow along with the makeup of their active agents. Cadmium, for example, comes from companies involved in manufacturing plastics, paint, fungicides, phosphate fertilizers and cadmium-containing batteries.

Heavy Metal

Cadmium is a heavy metal often implicated in herb and food contamination. It is toxic to humans and animals; it is carcinogenic and highly mutagenic. It damages the kidney and other organs and stays in the body for years after ingestion. Both herbs and food can contain harmful levels of cadmium.

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In 2012, a report out of China found 10 percent of the rice from China contaminated with excessively high amounts of cadmium.8 In fact, China is receiving an abundance of media attention for problems related to food and herb safety.

In 2013, Greenpeace startled the Chinese herb industry and consumers by publishing a troubling treatise about the amount of pesticides saturating Traditional Chinese Medicine compounds.

The research team purchased 65 Chinese medicine products in Hong Kong as well as on the Chinese mainland. Nearly three-quarters of the herbal mixtures contained up to 39 pesticide residues, six of which were banned in China. Nearly all of the banned pesticides had been supposedly off limits for over a decade. In one case, pesticide levels were 500 times the safe limits set by the European Union.

Some of the most popular Chinese herbs subjected to pesticide-intensive agriculture include notoginseng (a major constituent of Yunnan Baiyao), angelica, chrysanthemum, honeysuckle and wolfberry.

The Greenpeace exposé ignited a series of secondary stories around the globe. The news made its way back to China and even farmers producing the herbs, many whom were unaware of the products they were applying to their fields. Greenpeace representatives indicated that most of the farmers growing herbs such as honeysuckle and wolfberry were over 50 years of age and did not know how to apply the pesticides in a scientific manner. Some farmers remain illiterate, relying on the shape and color of the bottle in order to select pesticides rather than by reading the label and following dosing instructions.

Shockingly, the researchers reported, “Neither the government nor the manufacturer has any guidance for them. …They often take the advice of local shops, which tend to recommend highly toxic pesticides.”

Many farmers spread banned pesticides on their crops, unaware of the risks or regulations. Based on this false sense of security, they expose themselves and their young children to the chemicals, as family members typically participate in the process. “Middlemen” companies then purchase the plant products and purportedly “have no interest in pesticide usage; they only look at the honeysuckle colour and quality when deciding whether to buy.” Some Traditional Chinese Medicine companies may obtain the herbs through these “middlemen,” meaning that end-users might be unable to track the true source of the product and its safety.

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Curiously, even fresh culinary herbs imported from Southeast Asia serve as a source for contamination with multidrug resistant bacteria, i.e., enterobacteriaceae resistant to third-generation cephalosporins and quinolones. Eight of 10 batches of fresh herbs from Southeast Asia tested positive for contamination.

The problem extends worldwide, even outside of Asia, where herbs may contain molds, microbes and aflatoxins. For example, milk thistle botanical supplements can be contaminated with various fungi and their secondary metabolites known as mycotoxins.

In fact, some milk thistle preparations have been found to contain aflatoxins.19 Certain samples of dried chamomile were also found to harbor high amounts of microbial contamination that may relate to processing, storage, and moisture content.

Fake Organics

Is the solution reaching for organic herbs? That depends. Opting for organic may offer false comfort.

Since 2011, the USDA’s National Organic Program has been informing the public about fraudulent organic certificates. Over a two-year span, it identified 22 faked certificates, including nine from China. This affected, for example, Chinese extracts of hibiscus, jasmine and beet root that had been labeled as organic.

Consider the Source

Consumers concerned about herb, as well as food, safety, should be able to determine where the product was grown and, ideally, buy locally and know the source. This is what citizens in China are doing amid their own nation’s food scandals.

In addition, consumers should be on the lookout for a list of food (and herb) frauds.

These include origin fraud, or intentionally misrepresenting where a product originated in order to obtain a higher price; counterfeiting, or selling a fake as a lookalike to a popular product; species swapping, mislabeling a cheap variety of an ingestible product as a premium counterpart; simulation, such as coloring ordinary olive oil with chlorophyll so that it resembles virgin olive oil; and ethical deception, exploiting those who want to pay more for ethically sourced ingredients by disguising non-ethical alternatives.

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While DNA analysis can identify plant and animal genetic material in herbal remedies, aiding in identifying toxic plants and endangered species, companies also need to screen ingredients for microbes, mold, metals and pesticides.

Considering the paucity of safety and effectiveness data for many imported products sold today, one might ask, are they really worth the risk? For herbs that often lack scientific evidence of effectiveness and safety for most veterinary species, the question becomes even more crucial.

Originally published in the July 2014 issue of Veterinary Practice News

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