The folks at Science-Based Medicine and Respectful Insolence have been pointing out for a while that the Huffington Post has become a mainstream media champion for unreliable alternative medical information. And fortunately for us, HuffPo isn’t ignoring the veterinary side of alternative medical propaganda. Dr. Richard Palmquist, President-Elect of the American Holistic Veterinary Medical Association (AHVMA), of which I recently ran afoul, contributes a column to HuffPo. His latest commentary is instructive in that it illustrates the free mixing of reasonable ideas and science with nonsense made up out of thin air, in order to make the two indistinguishable and paint opinion and unsupported belief with a patina of scientific respectability.
In Veterinarians Team with Mother Nature for Better Results, Dr. Palmquist begins with the tried and true appeal-to-nature fallacy:
Scientists are pretty smart, but give them a bucket of carbon, oxygen, hydrogen, sulfur, iron, nitrogen and a few other miscellaneous things and see how many tomatoes they can make from scratch.
Nature is smarter.
Of course, scientists can’t whip up rattlesnake venom, syphilis, hookworms, tsunamis, or many other natural phenomena from scratch either. What’s the point here? If it is that what nature comes up with is better than what humans can make, I think that’s childish reasoning. “Nature” is just our personification of impersonal and undirected processes that have resulted in everything that exists, including human beings and their inventions, and it cares not a whit for our happiness and well-being. We like to say nature makes the good stuff, like puppies and strawberries, and we make all the toxic waste, but the reality is that nature made polio and we made the vaccine, so sometimes we are the good guys..
Dr. Palmquist then proceeds to make the true and quite reasonable observation that many useful medicines come from plants. Of course, this requires humans to analyze, purify, process, mimic, and test all sorts of compounds to find a few useful ones, none of which come without drawbacks, so how natural or inherently benign all of this is open to question. In any case, he inserts another assumption into this otherwise reasonable point, namely that the plants that contain substances useful as medicines were identified as medicinal and used to heal diseases by folk traditions a long time before science stumbled across their usefulness.
I am not aware of any evidence to support this notion, though it is commonly put forward by advocates of herbal remedies and traditional folk medicine in general. It may be true, but there are several reasons why I am doubtful of this assertion and would like something more than herbalists’ word for it. Prominent among them is confirmation bias, the tendency to focus on those examples which support one’s position and ignore those that don’t.
1. Many pharmaceuticals derived from plants, animals, fungi and other natural sources are discovered for reasons not related to folk medicine use. Someone notices that mold in a petri dish inhibits bacterial growth near it, and penicillin is discovered. Scientists work out that blowfish toxin paralyzes muscles and the chemical turns out to be useful in surgery. There are lots of reasons why a particular compound is pursued as a possible medicine apart from its traditional folk medicine use.
2. Most of the folk remedies one can find in historical documents turn out not to work reliably when tested, so Dr. Palmquist is guilty of counting the “hits” and ignoring the “misses.” If folk tradition were a reliable guide to which plants have medicinal value and which don’t, then the plants used in folk traditions should turn out to produce useful medicine more often and more reliably than those not so used. I have seen no evidence investigating this questions, so while it is possible it is by no means safe to assume it is true.
3. Almost every plant has been identified by some culture at some place and time to have medicinal properties. And when these properties are described, the plants are often said to treat a huge number of unrelated symptoms and diseases. When a plant turns out to contain a substance useful for a particular medical problem, one can almost certainly find a reference somewhere to that plant being used for that problem. This ignores the fact that the vast majority of claims made in traditional use of plants are either untested or shown to be untrue, so again Dr. Palmquist is cherry picking the examples where someone somewhere guessed right and ignoring all the wrong guesses.
4. As the post properly points out, getting medicines from plants almost always requires isolating, purifying, and altering chemicals to get better efficacy and fewer side effects. Most compounds investigated as possible drugs fail because they do more harm than good, or no good at all, and those that do succeed are often quite different from what one gets when eating plant parts directly. But Dr. Palmquist persists in putting forward the notion that a mixture of chemicals found in nature is likely to be safer and more effective than isolated and processed compounds. The evidence of medical history is soundly against this idea.
Certainly, it is true that combinations of medications are often more effective than single medications in managing complex diseases. But these are combinations of individual agents that are well-studied and understood and that have demonstrable benefit alone as well as in combination. And the sad reality is that combinations of drugs often leads to drug interactions which can be harmful. Dr Palmquist can say that Vitamin E is synergistic with NSAIDs for cancer therapy, but it is also true that Vitamin C diminishes the effect of some cancer treatments, so he is again picking examples that support his point and ignoring those that do not.
So why should we believe that the combination of chemicals found in a plant was somehow designed by nature to be ideal for treating a disease? Why should we think the combinations of plant ingredients created by folk medical traditions, arrived at either by uncontrolled trial and error or often fantastical theories based on religion, astrology, sympathetic magic, and so on, should be safer and more effective than medicines tested scientifically? Especially given the far greater success of medical science at treating diseases than any previous system has achieved in human history. And how do we explain the contamination of herbal remedies with toxins or even prescription drugs?[see references below] Dr. Palmquist answers none of these concerns but simply blithely assumes that what is natural and traditional is likely to be better than what is manmade and science-based.
There is no doubt nature, which after all describes everything that exists unless one arbitrarily chooses to exclude humans and their activities, holds many medical therapies yet to be discovered. But there is significant doubt that these therapies have already been identified in their safest and most effective form by herbalists and other folk medicine traditions. The reality is that science has taken not only the theories of these traditions but many other ideas they never conceived and created a wealth of medicines undreamt of before the age of scientific medicine. So to say nature knows best is at least naïve and at most an ideological even religious statement of faith rather than a scientific statement of fact. Dr. Palmquist is entitled to his faith like the rest of us, of course, but it should be clearly identified as such, not put forward by HuffPo as if it were established, accepted science.
Herbal Preparations, Including Ayurvedic and Traditional Chinese Medicine (TCM) Herbs:
Aliye Uc, MD, Warren P. Bishop, MD, and Kathleen D. Sanders, MD, Camphor hepatoxicity. South Med J 93(6):596-598, 2000,
Angkana R, Lurslurcharchai L, Halm E, Xiu-Min L, Leventhal H, et al. Use of herbal remedies and adherence to inhaled corticosteroids among inner-city asthmatic patients. Annal Allerg Asthma Immunol 2010:104(2);132-138.
Berberine. Inbaraj JJ, Kukielczak BM, Bilski P, Sandvik SL, Chignell CF. Photochemistry and photocytotoxicity of alkaloids from Goldenseal (Hydrastis canadensis L.) Chem Res Toxicol 2001 Nov;14(11):1529-34
Booth JN 3rd, McGwin G. The association between self-reported cataracts and St. John’s Wort. Curr Eye Res. 2009 Oct;34(10):863-6.
Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol 1999 Aug;246(8):667-70
Coon JT, Ernst E. Panax ginseng: A Systematic Review of Adverse Effects and Drug Interactions. Drug Saf 2002;25(5):323-44 Drug Saf 2002;25(5):323-44
Cupp MJ Herbal remedies: adverse effects and drug interactions. Am Fam Physician 1999 Mar 1;59(5):1239-45
Debelle FD, Vanherweghem JL, Nortier JL. Aristolochic acid nephropathy: a worldwide problem. Kidney Int. 2008 Jul;74(2):158-69. Epub 2008 Apr 16.
Emery DP, Corban JG Camphor toxicity. J Paediatr Child Health 1999 Feb;35(1):105-6
Ernst E Adverse effects of herbal drugs in dermatology. Br J Dermatol 2000 Nov;143(5):923-
Fugh-Berman A Herb-drug interactions. Lancet 2000 Jan 8;355(9198):134-8
Huang WF, Wen KC, Hsiao ML. Adulteration by synthetic therapeutic substances of traditional Chinese medicines in Taiwan. J Clin Pharmacol. 1997 Apr;37(4):344-50
Kutz GD. Herbal dietary supplements: Examples of Deceptive or questionable marketing practices and potentially dangerous advice. General Accounting Office. May 26, 2010.
Lai MN, Lai JN, Chen PC, Tseng WL, Chen YY, Hwang JS, Wang JD. Increased risks of chronic kidney disease associated with prescribed Chinese herbal products suspected to contain aristolochic acid. Nephrology (Carlton). 2009 Apr;14(2):227-34.
Lawrence JD. Potentiation of warfarin by dong quai. Page RL 2nd, Pharmacotherapy 1999 Jul;19(7):870-6
Means C. Selected herbal hazards. Vet Clin North Am Small Anim Pract 2002 Mar;32(2):367-82
Nizsly N, Grizlak B, Zimmerman M, Wallace R. Dietary Supplement Polypharmacy: An Unrecognized Public Health Problem? eCAM 2010 7(1):107-113
Norred CL, Finlayson CA Hemorrhage after the preoperative use of complementary and alternative medicines. AANA J 2000 Jun;68(3):217-20
O’Connor A, Horsley CA. Yates, KM “Herbal Ecstasy”: a case series of adverse reactions. N Z Med J 2000 Jul 28;113(1114):315-7
Pittler MH. Ernst, E Risks associated with herbal medicinal products. Wien Med Wochenschr 2002;152(7-8):183-9
Poppenga RH. Risks associated with the use of herbs and other dietary supplements. Vet Clin North Am Equine Pract. 2001 Dec;17(3):455-77, vi-vii
Pies R Adverse neuropsychiatric reactions to herbal and over-the-counter “antidepressants”. J Clin Psychiatry 2000 Nov;61(11):815-20
Prakash S, Hernandez GT, Dujaili I, Bhalla V. Lead poisoning from an Ayurvedic herbal medicine in a patient with chronic kidney disease. Nat Rev Nephrol. 2009 May;5(5):297-300.
Raman P, Patino LC, Nair MG. Evaluation of metal and microbial contamination in botanical supplements. J Agric Food Chem. 2004 Dec 29;52(26):7822-7
Ruschitzka F, Meier PJ, Turina M, Luscher TF, Noll G Acute heart transplant rejection due to Saint John’s wort. Lancet 2000 Feb 12;355(9203):548-9
Saper RB, Phillips RS, Sehgal A, Khouri N, Davis RB, Paquin J, Thuppil V, Kales SN. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet. JAMA. 2008 Aug 27;300(8):915-23.
Shad JA, Chinn CG, Brann OS Acute hepatitis after ingestion of herbs. South Med J 1999 Nov;92(11):1095-7
Smolinske SC J Am Med Womens Assoc 1999 Fall;54(4):191-2 Dietary supplement-drug interactions.
Tachjian A, Maria V, Jahangir A. Use of herbal products and potential interactions in patients with cardiovascular disease. J. Am. Coll. Cardiol. 2010 55: A32
Yang HY, Wang JD, Lo TC, Chen PC. Increased mortality risk for cancers of the kidney and other urinary organs among Chinese herbalists. J Epidemiol. 2009;19(1):17-23. Epub 2009 Jan 22.
Zhang SY, Robertson D. A study of tea tree oil ototoxicity. Audiol Neurootol 2000 Mar-Apr;5(2):64-8