This is Part 3 (of 4) in the Supplement Savvy series by Jeremy Appleton, ND, CNS. Other articles include:
Part 1: Understanding Food and Supplement Labels
Part 2: Product Potency
Part 4: Quality and Purity
Dietary supplements containing botanical ingredients are popular for many uses: garlic is used to support normal cholesterol levels, St. John’s Wort is well known for boosting mood, Echinacea is used by millions for immune support. These are just a few of the many herbal supplements sold without prescription in the United States under the Dietary Supplements Health and Education Act (DSHEA). Many herbal products are safe and effective. However, the DSHEA guarantees neither their safety, their efficacy, nor even that the products are what they say they are. If the Food and Drug Administration discovers that an herbal product does not meet its label claims, it has the authority to pull the product; however, there are no pre-market requirements for potency or authenticity for any herbal product.
As a result of this, there are a great many herbal products on the market that do not, in fact, meet their label claims. Either they contain less than the amount of the herb stated on the label, or the standardization of active constituents is not in agreement with the label, or the identity of the plant itself is not the same as what is listed on the label. There are many reasons these discrepancies can occur, ranging from the inadequate quality control in harvesting or processing to deliberate adulteration of products with other (usually cheaper) ingredients.
There are a variety of methods that scientists and manufacturers use to verify the identity of plants and plant constituents in supplements. These methods are typically carried out in a laboratory setting, and include high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), mass spectrometry, and others. For each substance tested, the method of testing must be validated; otherwise, there can be unacceptable variance in standards applied to different plants and constituents.
Some manufacturers find these tests, or the validation process, to be unacceptably expensive to run on every lot of material they produce, so random testing is sometimes employed. Other times, especially with smaller companies, the tests are omitted altogether. However, even when other quality control measures are followed to ensure the identity and potency of a plant, laboratory testing is still necessary for positive confirmation. In many cases, validated laboratory testing methods have not even been developed.
Consider the following case-in-point. Black cohosh (Actaea racemosa; also known as Cimicifuga racemosa) is an increasingly popular dietary supplement in the United States for the treatment of symptoms related to menopause. However, the botanical authenticity of most products containing black cohosh has not been evaluated. In one study (Jiang et al, 2006), 11 black cohosh products were analyzed for their main active constituents, which in black cohosh are 1) triterpene glycosides, 2) phenolic constituents, and 3) formononetin. The researchers used a modified, improved version of HPLC / mass spectrometry to quantify the presence of these active constituents. Three of the 11 products were found to contain a key marker compound (cimifugin) and not one of the key identifying glycosides. This indicated to the researchers that these samples contained not black cohosh, but another species of plant in the Actaea genus. (In the Latin naming system, plants are identified first by genus, then by species. So for black cohosh, the correct genus is Actaea and the correct species is racemosa.) One product was found to contain both black cohosh and an Asian Actaea species. Even among the products that were not adulterated (i.e., that contained only black cohosh), there was significant product-to-product variability in the amounts of the active constituents. This can occur for a variety of reasons, including where the plant is grown, under what conditions, when it is harvested and how it is stored.
Consumers may understandably find the range of considerations around botanical quality to be daunting. It is impossible for anyone without a laboratory to assess a botanical product’s quality; you cannot tell just by looking at it, or smelling it, or tasting it. However, there are some things to look for in the company that makes the product that can provide assurance of an authentic product of acceptable potency:
- Does the manufacturer follow FDA Good Manufacturing Practices for Dietary Supplements?
- Can the manufacturer provide lot-specific certificates of analysis for every ingredient used in their formulas?
- Are herbal raw materials purchased by the manufacturer through distributors, or directly from farms that grow the plants?
- Does the manufacturer submit its products for identity and potency validation to a qualified laboratory, and are those results available for review.
By asking a few pointed questions of a manufacturer’s technical director, it is possible to get a good sense of the quality of thir products.
In the final part of this four-part series, Quality and Purity, we will examine the critical factors and challenges that affect supplement quality and purity — and how you can use your supplement savvy to choose top quality supplements.
Jiang B, Kronenberg F, Nuntanakorn P., et al. Evaluation of the Botanical Authenticity and Phytochemical Profile of Black Cohosh Products by High-Performance Liquid Chromatography with Selected Ion Monitoring Liquid Chromatography-Mass Spectrometry. J Agric Food Chem2006;54(9):3242 -53. Free full text available online at: http://pubs.acs.org/cgi-bin/sample.cgi/jafcau/2006/54/i09/pdf/jf0606149.pdf (Accessed 9/25/08)