Are Herbal Supplements Safe?


The New York Times had an article this week, Herbal Supplements Are Often Not What They Seem, that suggested that herbal capsules may not contain what they say, often containing different species in the family or fillers.  The study cited is found here.

The study has major problems and the American Botanical Association has called upon the BMC medicine journal to retract the paper:

In our view, and in the opinion of expert reviewers of this critique, and with all due respect to the authors and BMC Medicine, the journal should retract this paper, and require that the authors address various errors, ambiguities, and areas of confusion by appropriately rewriting, correcting, and resubmiting it to the journal. The editors of the journal should then submit the corrected revision to an appropriate peer-review process that employs numerous expert reviewers (not just the two who presumably reviewed the initial paper) who are knowledgeable not only in the fields of DNA testing, but also in botanical analytics and related disciplines. Only then, if the paper passes such appropriately expanded peer review, should the paper be republished. Until then, despite the good intentions of its authors, this paper creates confusion, promotes false conclusions, and, unfortunately, may constitute a disservice to scientific researchers and other responsible members of the botanical products community.

Herbalism (Photo credit: Nomadic Lass)

The DNA barcode study looked at extracts as if they were herbs.  Herbal extracts do not contain complete DNA from the plants, but instead concentrate constituents from the plants.  You need fewer capsules of extract than of powdered herb which is why most capsules contain  extracts or extracts spray dried onto carriers.  The extracts usually require a solid base which can range from the herbal marc, to rice to alfalfa, or they will clump and not break down well in the body.  But in the study the extracts were seen as missing herbs and the excipients and fillers were seen as adulterants.

While it was not possible to tell the difference between slight contamination- a few dandelion leaves in a hectare of herbs or wholesale substitution of amaryllis family for cinnamon, we know there is some adulteration  in the herbs supply, just not most of it as the study implies. In an era where most herbal products are subject to intense Good Manufacturing Practice (GMO) and third party verification there is less adulteration than one might think.

Still, I almost never suggest using encapsulated herbs, for reasons of identification and freshness, as well as because taste is an important signal to the body that the herbs are coming and to start secreting digestive juices to use them.  Besides, herbs you taste can get into the lymphatic system in your tongue and throat, instead of waiting in your stomach for the gel cap to dissolve.  But I had several reactions to the article:

  • We have adulterated olive oil, e-coli in meat, melamine in pet food, banned pesticides in our fruit,  counterfeit or badly studied pharmaceuticals and bottled tap water sold as “fresh from the spring”.  In all cases, including herbs, the regulations are strong but the FDA is pitiful at enforcing them.  Frankly I prefer that they focus on hamburger and chicken since it causes more health problems.  Misidentified herbs, which I abhor, have not killed anyone. But we have nowhere enough inspections for an internationally sourced food and medicine supply.
  • The herbs you purchase from your acupuncturist, herbalist or naturopath are not likely to be a problem.  I prefer to use fresh herbs which I was trained to inspect, purchased directly from growers I have met in the US or firms which use liquid chromatography and a variety of other means to test for species, heavy metal contamination or other problems. I use five exceptional tincture companies or make tinctures myself.  Serious herbalists, many of whom I know started companies to help heal people. The granules I use are from Taiwanese firms with pharmaceutical-grade manufacturing, certified GMP (good manufacturing practice compliant) and have third party inspection certificates.  When I do use teapills or capsules I purchase from firms that I know to be careful, from a Chinese medicine pharmacy that inspects sources or from high quality US firms.
  • Be careful where you get your herbs if you buy them yourself.  I don’t purchase herbs from my local CVS or even GMC. We have a high quality independent health store where the proprietor is careful to select brands with good quality standards.  You can grow your own herbs for teas or tinctures. There are quality mail-order herbs.  Ask questions. Join Consumerlab and purchase the supplements that have passed their tests for species, potency and heavy metals. Ask for GMC compliance and third party verification.
  • It appears that the test in the article was to promote a new DNA bar code scanning technology to be a standard, although it can identify herbs, but  not when they are processed or in formulas and which can neither account for potency or heavy metal contamination.  (See the Consumerlab founder’s letter at the bottom of the NY Times article.)  While this does not excuse the mislabeled herbs, the actual percentage is likely under the  amount identified in their study.

    Herbal supplements
    Herbal supplements (Photo credit: Ano Lobb. @healthyrx)
  • Some species are similar to others and have similar properties, others not.  In Chinese medicine a pharmaceutical name like niu xi may refer to several functionally similar species although they really ought to be identified. by Latin binomial species name.  The black cohosh (Actea racemosa) cited in another study had Actea asiatica substituted, but that plant is used in Chinese medicine and really is not a serious risk for toxicity at normal doses.  It is used differently though.  Echinacea species usually have similar properties.
  • Most capsules are made with herbal extracts where constituents from plants are extracted but the DNA is not present.  This would show up with the barcoding as missing the herb when in fact it is the basis of the extract.
  • Keep it in perspective.  Hundreds of thousands of people each year die from properly-identified pharmaceuticals while you need to go back several years to find any deaths from herbs, properly identified or not.

The study does not name manufacturers by name,  which would have been helpful.  Here are some herb companies I deal with which I consider safe and accurate:   Herbalist & Alchemist, HerbPharm, Cedar Bear Naturals, Mountain Rose Herbs, Zach Woods Herb Farm, Healing Spirit Herb Farm, Blessed Maine Herbs , Wise Women Herbals, Mushroom Harvest, Plum Flower, Lotus Herbs, Gaia, Spring Wind Herbs, KAN, KPC, Kamwo Herbs, New Chapter, Starwest, Frontier, Pacific, and there are many, many more.


Addenda:  The American Botanical Council has called for a recall of the study because of its serious failures.  Here are a few extracts from its critique:

” The approach taken by the authors was to create a number of homemade definitions and then evaluate materials against those definitions using DNA fingerprinting. …There are internationally recognized definitions for identity, authenticity, contamination, and substitution. Invention of new definitions for these terms by the authors in order to demonstrate the novelty of their approach and their technical virtuosity is self-referential and, unfortunately, very possibly self-serving. Their apparent lack of adequate knowledge in this field has allowed them to create a virtual problem and then, figuratively, ride to the rescue and solve it.”

Despite the authors’ contention to the contrary, there is no evidence that DNA can be obtained from botanical extracts, and DNA from relatively highly processed materials such as finished supplements in tablets and capsules is of poor quality. As a result, the DNA that is detected in these cases is typically either accidental environmental contamination, cross-contamination among samples in the lab, and/or the DNA from the product’s carrier or filler (soy, potato, or rice).

… In the same PCR reaction mix, a shorter fragment (e.g., from the adulterant) is preferably amplified over a larger fragment, which also could be misinterpreted to mean that the sample has more adulterant material than authentic material…We thus are at a loss to know whether or not non-target DNA found in a product is present at levels that would constitute a significant amount of extraneous material or perhaps a few dandelion (Taraxacum officinale, Asteraceae) leaves commingled with a hectare’s worth of harvested crop.

22 people like this post.


Leave a Reply

Your email address will not be published. Required fields are marked *