Herbal supplements, also called botanicals, are classed by the FDA as dietary supplements. They usually come in the form of pre-packaged capsules or tablets containing plants or parts of plants such as flowers, leaves, bark, fruit, seeds, stems and roots, either singly or in combinations. Popular herbal supplements include echinacea marketed to prevent colds, ginkgo marketed to improve memory and flaxseed marketed to lower cholesterol and so on.
Herbal supplements are often promoted as being ‘all natural’ and because they are sold as dietary supplements rather than drugs, they are not as strictly regulated as medications. Reputable manufacturers are expected to follow good practice to ensure that supplements are processed consistently to meet quality standards and are free from contaminants such as pesticides and lead. While herbal products in the United States, the UK and some European countries are highly regulated, toxic ingredients and prescription drugs have been found in supplements manufactured elsewhere, particularly China, India and Mexico. Emeritus Professor Duncan Burns, an analytical chemist from Queen’s University Belfast’s Institute for Global Food Security, said in a press release. “We have found that these supplements are often not what customers think they are — they are being deceived into thinking they are getting health benefits from a natural product when actually they are taking a hidden drug.” A 2013 study published in the journal BMC Medicine found that one-third of herbal supplements sampled contained no trace of the herb listed on the label. The study found products adulterated with filler including allergens such as soy, wheat and black walnut. One bottle labelled as St. John’s Wort was found to actually contain Alexandrian senna, a laxative. Researchers at the University of Adelaide found in 2014 that almost 20% of herbal remedies surveyed were not registered with the Therapeutic Goods Administration, despite this being a condition for their sale. They also found that nearly 60 % of products surveyed had ingredients that did not match what was on the label. Out of 121 products, only 15 had ingredients that matched their TGA listing and packaging. In 2015 the New York Attorney General issued cease and desist letters to four major U.S. retailers (GNC, Target, Walgreens, and Walmart) who were accused of selling herbal supplements that were mislabelled and potentially dangerous. 24 products were tested by DNA barcoding as part of the investigation, all but five contained DNA that did not match the products’ labels. The investigation was prompted by the 2013 BMC study.
The chemical makeup of a herb can vary, depending on environmental factors, so most herbal supplements come as standardised extracts to overcome this, in which one or more components are present in a specific, guaranteed amount. This practice developed out of the drug model of conventional medicine in which scientists have attempted to identify the components of a plant which have pharmacological activity in the body. Consequently, standardisation may concentrate one constituent at the expense of other potentially important ones (most St. John’s wort tablets and tinctures are standardised for hypericin, for example, but the latest research shows that hyperforin is the real active ingredient), while changing the natural balance of the herb’s components. Standardisation is based on the idea that isolated compounds are responsible for the action of a herb, but there is evidence that this is may not be the case. An article several years ago in JAMA on use of ginkgo biloba to counter dementia explained that no active ingredient from among the several hundred constituents present had been determined and it was, in fact, likely that the effect resulted from a complex, synergistic interplay of the parts. In other words, the whole plant contains a range of chemicals which seem to work in concert. This makes it doubtful that this type of standardised herbal extract can exhibit the same full spectrum of use as the whole herb. There is a second form of standardisation, however, which uses key components only as markers of identity while trying to maintain the same full spectrum of components as the whole herb, assuring that no major component has been removed in the extraction process, and if supplements are used, these are thought preferable by herbalists of the synergistic school of thought.
© Anna Franklin