Pet Food Nutrition Myths

Posted on July 15, 2009 by skeptvet

I’ve previously written an analysis of one of the most popular veterinary nutrition myths, the idea that cats and dogs should eat raw food. I was recently asked by one of my colleagues to address a couple of other veterinary nutrition myths, and by a happy coincidence Dr. David Dzanis, a board-certified veterinary nutritionist and consultant, gave a brief talk on the subject at the American Veterinary Medical Association conference from which I just returned. While I hope to someday put together a more comprehensive and thoroughly referenced list of such myths, I thought I’d share a few tidbits I learned from Dr. Dzanis, and a few other sources, on the subject of pet nutrition.

 

“Good” vs “Bad” Ingredients

Popular mythology assigns food ingredients statues as “good” or “bad,” ill-defined categories which are seldom based on any scientific facts but which have a powerful impact on the purchasing decisions of the pet-owning public. Unfortunately, pet food manufacturers play along and exacerbate this mythologizing of certain food ingredients for marketing advantage. When the public begins to believe a common ingredient is harmful, manufacturers will sometimes begin proudly announcing their foods are free from the ingredient, and this will appear to be confirmation of the myth. The chemical preservative ethoxyquin is a perfect example. While there is no evidence this ingredient causes any harm, and it is clear that spoilage of “preservative free” food can pose a real health risk, the ingredient is now rarely used because uninformed and unscientific public opinion demanded its removal from pet foods. A similar sort of process lead to the removal of thimersal from human vaccines despite the clear science refuting the public concerns about this preservative.

Often the growth of a movement against a food ingredient  is a purely aesthetic issue with no scientific merit. Eating chicken feet and viscera, unborn calf fetuses, and so on sounds gross, so people assume these aren’t healthy pet food ingredients. But the aesthetic standards of cats who like to chew on dead lizards and dogs who eat socks, rubber, and poop are different from ours, so it’s a meaningless way to judge such food constituents.

Such food ingredients are also disdained because of the confusion in many people’s minds of nutrients and foods. People will claim that “sea salt” is somehow different from mined salt or that wheat proteins are somehow less nutritious than beef proteins. The fact is that, properly prepared, many things we would not consider appropriate as foods in their original state can provide vital nutrients of the same quality, or better, as more aesthetically pleasing sources.

It is particularly common these days for people to claim that grains are “bad,” and that wheat and corn in particular are harmful or “allergenic” for our pets. As Dr. Dzanis puts it, “Corn and wheat are often criticized as inferior to other grains such as rice. While rice is generally more digestible than corn, that also means the starches are reduced to sugars and absorbed much more quickly. This may not be desirable for animals with clinical problems related to blood glucose control. As far as potential allergenicity, historical use of rice in therapeutic diets as a “novel ingredient” for diagnosis or control of food allergies may have led to a false impression. In cases where the cause of a food allergy has been determined, the incidence of allergy to corn is equivalent to the incidence of allergy to rice.”

The popular suspicion of wheat is likely related, to some extent, to the incident in which a Chinese firm supplying many American pet food manufacturers with wheat gluten adulterated their product with melamine, leading to kidney failure, sometimes fatal, in pets who consumed the tainted food. While this is a tragic and infuriating example of venality and inadequate regulation in China, it has nothing to do with the appropriateness of wheat as a pet food ingredient. And while a few breeds, such as the Irish Setter, have genetic gluten sensitivity, in general wheat is a healthy and nutritious ingredient perfectly appropriate as an energy and protein source in pet food.

Corn has also gotten a sinister reputation from popular author Michael Pollan. While I enjoy, and agree with, the balance of Mr. Pollan’s writing, his indictment of the corn industry and the use of corn-derivatives in food products can easily encourage an irrational and hysterical assessment that corn is somehow poisonous and nutritionally vacuous, which is simply not true. Corn and wheat proteins are common allergens for dogs and cats not because they are especially “allergenic” but simply because they are common proteins in pet food. As they are replaced, under the misguided pressure of public mythology, with rice and soy and so on, these newer ingredients will become the predominant allergens in pets who develop hypersensitivities or true allergies to commercial foods.

Hidden Food Ingredients

Pet food manufacturers are often accused of slipping roadkill, old shoes, and all sorts of other bizarre and disagreeable things into commercial pet food. While these companies exist to make a profit and certainly do what they can do encourage the public to view their products favorably, even if this involves a little slight-of-hand when it comes to describing the content of their foods, the reality is that they are legally required to identify any ingredient they use, and there is no evidence that they ignore this requirement in any routine or egregious way. Which brings me to one off the most shocking, and farfetched, concerns about pet food:

Dead Pets in Pet Food

Soylent Green is….Rover? Probably not. Promoters of this story take a few facts and weave them into an unlikely, but shocking narrative. It is true that in some parts of the country, euthanized dogs and cats are disposed of by rendering, a process which breaks whole carcasses down into potentially useful constituents. This is usually done by commercial services, and at facilities, not associated with slaughter and rendering of the agricultural animals generally used as pet food ingredient sources. however, the practice of using rendered cattle as an ingredient in cattle feed, and the subsequent epidemic of Bovine Spongiform Encephalopathy (BSE, aka “Mad Cow Disease) illustrates that there are potential risks to such practices. However, from a purely economic point of view, using rendered pets as an ingredient in pet food makes no sense. Additionally, the Pet Food Institute, an industry lobby which represents the manufacturers of  ~98% of commercial pet foods, specifically prohibits rendered pet ingredients in their members’ products.

 

FDA studies in 1998-2000 did find miniscule quantities of pentobarbital (2-32 parts per billion) in many commercial pet foods. This is an anesthetic often used to euthanize animals, and the finding provided some ammunition for those who claim dead pets have made their way into pet foods.

However, the same studies did not find any cat or dog DNA in the proteins from any of the tested foods. While the source of the pentobarbital was not identified, the best guess is that it comes from small numbers of cattle or possibly horses euthanized and then rendered and used in pet foods. In any case, follow up studies estimated the minimum amount of pentobarbital which has any measurable physiological effect and found that even the smallest dog eating large amounts of the food with the most pentobarbital could not get to this dose. So while the FDA cannot guarantee, that no rendered pet material ever makes it into any pet food, it is highly unlikely, and there is no evidence that even if this were the source of the anesthetic detected that there is any health risk associated with such miniscule amounts of the contaminate.

People concerned about such “toxins,” whether in food or vaccines, often fail to understand the concept of dose-dependent toxicity. As I’ve pointed out before, water and oxygen can kill in sufficient doses, despite being vital for life. And even an anesthetic which, when given as an overdose can kill, can be harmless in quantities measured in parts per billion.

The Role of AAFCO (Association of American Feed Control Officials)

AAFCO is a private organization that establishes non-binding guidelines for the production of animal feeds, including pet foods. While it is not a government agency, only government officials can be members. Most are from the U.S. but there are members from the FDA/USDA equivalents in other countries. It is often labeled, by promoters of raw or home-cooked pet diets, as an organ or lackey of the pet food industry. Industry and private groups can attend AAFCO meetings and contribute advice or information to task forces or working groups, but they cannot vote. Such groups have included pet food manufacturers, but also veterinary groups such as the Academy of Veterinary Nutrition, the American Veterinary Medical Association, and the American Animal Hospital Association, as well as advocacy groups such as People for the Ethical Treatment of Animals, Defend Our Pets, and others.

AAFCO creates guidelines and models but has no regulatory authority. However, their ingredient definitions and nutritional standards are often adopted by the FDA in their regulation of pet foods.  A food can be certified as meeting AAFCO standards based on nutrient analysis done by the manufacturer. Or it can be certified as “feeding trial tested” based on trials conducted by the manufacturer. These often last 10weeks (for growth diets) to 6 months (for maintenance diets) and involve regular clinical and laboratory monitoring. Unfortunately, a food can also be certified as “feeding trial tested” without an actual feeding trial if it is ruled by FDA substantively similar (in the same “product family”) to a food that has undergone feeding trial testing. Clearly,, this is less than ideal but without the political will to fund government testing of all pet foods marketed, these standards at least ensure a minimum level of adequacy, and they are certainly preferable to the complete lack of standards that apply to most home-cooked diets or those marketed outside the official regulatory system. Which leads me to the last category of veterinary nutritional mythology:

“Natural” and “Organic” Foods

By legal definition, to be “natural” an ingredient must come from an animal, plant, or mined source and must be minimally processed (it can be heated, fermented, and so on). Most vitamins added to foods are synthetic and do not meet this requirement. However, to be legally marketed, “natural” foods must still conform to the nutritional standards established by AAFCO and regulated by the FDA. There is zero evidence, of course, that this designation has anything to do with the safety or nutritional value of a food/food ingredient. It’s really a marketing issue, not a scientific one. The popularity of this designation is an example of the “naturalistic fallacy,” the idea that “natural” is synonymous with “good” or “healthy.” Salmonella, hydatid cyst disease, poison oak, and gamma radiation are all “natural,” while most antibiotics, antiparasitics, anti-inflammatories, and cancer treatments aren’t, but if I am unlucky to run into these “natural” things I’d sure like to have the “unnatural” ones around .

“Organic” foods and food ingredients, similarly, have a specific legal definition, enforced by USDA not FDA, that has detailed requirements for how a food ingredient can be grown and processed. The best way to ensure something is truly “organic” is too look for the USDA Organic seal. There is no evidence that food produced by these standards is superior in terms of health and nutrition. There is, however, good evidence that organic production methods have less harmful impact on the environment than more common industrial methods, so there may be some value to the designation despite its unfortunate affiliation with the mythology of the naturalistic fallacy. 

References

 

 

Comprehensive proceedings from the 2009 Hill’s Symposium on Nutrition Myths and Truths, Facts and Fallacies. Cats and Carbohydrates- What are the Concerns.

Cowell CS, Stout NP, Brinkmann MF, et al. Making commercial pet foods (Ingredient myths and facts). In: Hand MS, Thatcher CD, Remillard RL, et al. P (eds). Small Animal Clinical Nutrition, 4th

Edition. Topeka, KS: Mark Morris Institute, 2000; p. 141.

 

Food and Drug Administration/Center for Veterinary Medicine: Report on the risk from pentobarbital in dog food [Online]. Available: http://www.fda.gov/cvm/FOI/DFreport.htm. 31 March 2009.

 

 

Posted in Nutrition | 47 Comments

The David and Goliath Myth

Posted on July 8, 2009 by skeptvet

CAM proponents often present a picture of the relationship between CAM and mainstream medicine that is as dramatic as it is fanciful, and it bears a resemblance to the myth of David and Goliath. Scientific medicine is portrayed as a venal cabal of big corporations and corrupt government bureaucracies determined to maintain a lucrative monopoly on health care by suppressing safe and effective, but unprofitable natural cures such as herbs, homeopathy, acupuncture, chiropractic, reiki, and so on. CAM, in contrast, is portrayed as a loosely-affiliated network of individual healers all dedicated to promoting health and well-being and to bringing people the freedom to choose their own path to wellness outside the rigid and coercive structures of government, the Cancer Industry, Big Pharma and the rest of the nefarious medical-industrial complex.

Like most myths, this one contains a few grains of truth amidst the chaff of fantasy and marketing. The pharmaceutical industry, for example is enormous, wealthy, and driven primarily by profit. While there are many individuals working in pharmaceutical and biotechnology research who are dedicated to relieving suffering through science, the institutions exist as entities of the market, and as such they often prioritize their efforts based on profitability, and they often work vigorously to manipulate health care providers, consumers, and government in ways that have more to do with return on investment than promoting health and welfare. Any corporate, for-profit company must consider making money a goal or it ceases to exist. This is true for pharmaceutical companies veterinary hospitals, and — hey, wait a minute. It’s true for herbal medicine manufacturers, dietary supplement companies, chiropractors, acupuncturists, and all those CAM folks too!

Reliable figures are hard to come by, but there’s no doubt CAM is big business. In 2005, consumers spent more than $21 billion on supplements in the U.S. and $66 billion worldwide, according to the Nutrition Business Journal (1). One study estimates total annual CAM sales at £4.5 billion in the UK, $2.4 billion in Canada, and $80 million in Australia.(2) Many of these supplements are sold by corporate giants such as Herbalife (2008 earnings $2.15 billion) and GNC (2008 earnings > $16 million). And even 10 years ago mainstream pharmaceutical giants were getting involved in the vitamin, supplement, and herbal products market, and this involvement has only increased. Most veterinary herbal and neutraceutical products are manufactured by the same pet food and drug giants the CAM community so derides. So in many ways, Big Pharma is Big CAM.

The image of alternative medicine providers as individuals fighting to practice and tell their side of the story against the organized opposition and censorship of mainstream medicine is also disingenuous. The supplement and herbal medicine industry is highly organized and has a vigorous, well-funded lobby that has successfully fought government attempts to regulate their products in a way comparable to other medicines on the market. The United Natural Products Alliance and the Council for Responsible Nutrition are among the biggest supplement industry advocacy and lobbying groups, and they have aggressively and successfully supported a fox-guarding-the henhouse strategy of industry self-regulation and opposed government attempts to require published evidence of safety and efficacy for their products.

Chiropractors are also highly organized, well-funded, and politically active. They successfully defeated the efforts of the American Medical Association to curtail the acceptance of chiropractic as legitimate by government and the health insurance industry. After organizing to defend individual chiropractors against injury lawsuits, the chiropractic lobby supported a successful anti-trust lawsuit which has left the AMA very reluctant to oppose the spread of chiropractic despite its poor evidence of efficacy and its very real risks. (3)

And in the United Kingdom, The British Chiropractic Association has successfully pursued a libel lawsuit against Simon Singh, a journalist who wrote an article in the Guardian Newspaper critical of their promotion of chiropractic for childhood asthma, colic, and other conditions for which chiropractic is proven ineffective. Hundreds of thousands of pounds have been spent by the chiropractic lobby suppressing the evidence-based opinion of one journalist in one newspaper article. This is hardly consistent with the image the industry promotes of itself as the well-meaning and plucky underdog.

CAM proponents often complain about the resistance to their ideas in academic institutions, and portray themselves as inheritors of folk tradition and wisdom that does not require academic validation. Yet they aggressively promote their agendas in these same academic institutions and set up their own credentialing and degree programs to take advantage of the legitimacy and respectability conveyed by the imprimatur of academic institutions they disdain.(2) And while CAM proponents talk about “health care choice” and keeping government out of the business of regulating the claims of health care products, they have successfully supported spending over $1 billion of taxpayer money through the National Center for Complementary and Alternative Medicine at the NIH on research which has yet to validate and clinically significant CAM therapy.

So while the CA as David and the Medical/Industrial Complex as Goliath marketing strategy has been creative and effective, it is not an accurate portrayal of reality. In both CAM and scientific medicine, there are mostly hard-working people genuinely dedicated to relieving suffering. And in both areas, there are venal and unscrupulous individuals seeking money, fame, and other self-serving goals. This has no bearing on the issue that should be the center of any discussion about CAM and science-based medicine, which is what works and what doesn’t. The David and Goliath frame is a fantasy designed to distract from the realities of the evidence and to shield the CAM industry from the scrutiny and supervision mainstream medicine is expected to undergo.

1. Hurley, D. Natural Causes: Death, Lies, and Politics in America’s Vitamin and Herbal Supplement Industry. Broadway Books, New York. 2006.

2. Shapiro, R. Suckers: How Alternative Medicine Make Fools of Us All. Vintage Books, London, 2008.

3. Ernst, E., Singh, S. Trick or Treattment: The Undeniable Factts About Alternative Medicine. W.W. Norton & Company, New York. 2008.

Posted in General | 5 Comments

Licensing Woo in WA

Posted on July 5, 2009 by skeptvet

A fellow veterinarian recently drew my attention to a glaring example of the disconnect between the logic of science and the logic of politics, and how Big CAM is, sadly, better at playing politics than scientists seem to be. A proposal has been filed with the Washington state Department of Health to revise the scope of practice for acupuncturists. Apparently, the acupuncture lobby in Washington(1) wants to expand its role in primary health care beyond sticking needles in people. What they are requesting is:

“the addition of seven modalities that will enhance public health. These
modalities are: breathing, relaxation, and exercise techniques; qi gong, health education; in-office testing of temperature, blood pressure, oscultation[sic], weight, body fat percentage, urine, saliva, stool, and blood to assist the practitioner in determining the need for referral to a primary care physician and to assist in treatment; massage and tui na; heat and cold therapies; and recommendations and dispensing of herbs, vitamins, minerals, and dietary and nutritional supplements.”

They would like this new conglomeration of diagnostic and therapeutic techniques to be labeled “Asian Medicine” by the state, since “Acupuncturist” implies they limit themselves to acupuncture, which they clearly do not. Now, it would seem from the perspective of science that the logic of licensing acupuncturists is itself not ironclad. A method of therapy that has never demonstrated itself to be more than an unusually good placebo gains more from the implicit endorsement of government licensure than the public health would seem to gain from regulating the practice. Still, one could argue that regulations such as requiring disposable sterile needles and so forth might be appropriate to minimize the admittedly small harm that acupuncture can do since people are going to have the treatment whether it is licensed or not.

But giving official imprimatur to a hodgepodge of techniques united only by their basis in ephemeral, and unverifiable, energies and forces seems questionable. And allowing practitioners of such methods, who frequently denounce the core principles of scientific medicine, including the germ theory of disease, to handle body fluids and make themselves the first line of primary health care seems obviously misguided. But the logic of politics is not the logic of science. Public demand for the services involved, and the marketing successes of the applicants, will likely count for more than any hard evidence that the practices involved are ineffective and based on erroneous theories.

Still, the political playing field is one we in science-based medicine had better get used to if we truly want to serve public health. So any of you in Washington, take a lok at the proposal and make your voices heard.

1. American Association of Acupuncture and Oriental Medicine (AAAOM)
PO Box 162340
Sacramento, CA 95816
916-443-4770
916-443-4766 Fax
866-455-7999 Toll-Free
Washington Acupuncture and Oriental Medicine Association (WAOMA): 223 members
Advocates for the Advancement of Asian Medicine (AAAM): Unknown number of members
South Sound Acupuncture Association: 29 members
Southwest Washington Acupuncture Group: 26 members

Posted in Law, Regulation, and Politics | Leave a comment

Neoplasene-The Latest Head of the Escharotic Hydra

Posted on July 5, 2009 by skeptvet

A reader recently drew my attention to a form of CAM that is particularly dangerous and irresponsible but that like the mythological Hydra manages to raise its ugly head again and again despite efforts to kill it. Its latest incarnation in the veterinary field is as Neoplasene, yet another example of how CAM can achieve success through marketing unsupported by any evidence of real benefit.

According to the marketing materials, the ingredient in Neoplasene is “one of the prominent candidates deserving of the wonder drug designation.”(1) Pretty exciting, no? The promoters go on to follow the well-traveled road of CAM marketing, explaining why scientific medicine has missed the obvious truth, and only the iconoclastic promoters of the “wonder drug” can see it. “[Pathologists] clearly have not made reliable sense out of biopsy analysis…they just aren’t up to the task of reliable diagnostics.”(1) Of course, that doesn’t really matter since “this author…believes that inordinate attention is paid to diagnostics because, until now, little could be done to eliminate neoplastic disease so instead of treatment mainstream protocol has been to study the symptoms a lot and treat the disease a little.”

Oh, instead of studying the disease, we should be treating it!!! Gosh, how could we have been so blind? Oh, maybe because of “the barriers to the development and use of really effective cure oriented chemical treatment of neoplasm which are intertwined with political, economic and regulatory realities.”(1) See where this is going? “Cancer treatment and research are big business. Tremendous resources of facilities, personnel and funding are allocated to address education, equipment, real estate, personnel and patented designer drugs. Big organizations have momentum; they do not change direction easily or quickly…It has been viewed by drug developers that patentability may not be attained on some pharmaceuticals.”(1) So we in mainstream haven’t seen that “these alkaloids clearly attack neoplasm preferentially” and “this fact has been known and largely ignored by pharmaceutical researchers for nearly two hundred years” because of institutional inertia and the fear that we won’t make back the cost of developing such a miraculous cancer cure.

Such clichés seem as obviously ridiculous and unbelievable as the fake moon landing sort, yet they are just as persistent, and even more dangerous in that they drive people away from real medicine and into the arms of CAM.

The Neoplasene marketing materials go on in some detail, using testimonials and sloppy semi-scientific verbiage to clearly claim that the product treats, and even cures cancer, despite a few lame disclaimers to the contrary. And what is this miracle elixir the bloated bureaucracy of scientific medicine has overlooked?

Neoplasene is a derivative of bloodroot, which is one of several caustic herbal products known as escharotics(2). When applied topically in sufficient concentrations, these derivatives burn the flesh and cause tissue necrosis, often leaving thick scabs called eschars, and tremendous local devastation of healthy tissue. The danger of these products is well-illustrated by case reports in the scientific literature(3,4). Though the promoters claim the chemicals somehow recognize cancerous tissue and spare healthy tissue, there is no clinical evidence of this. Some preliminary in vitro research certainly shows the chemicals can kill cells. And there is some limited evidence that they may even be better at killing diseased cells than healthy cells in culture.(5) But when you smear the stuff on your skin to “draw out” the neoplastic cells and leave untouched the healthy tissue, you’re likely to wind up with a gaping hole and a lot of plastic surgery to look forward to. If you’re especially lucky, though, some deeper neoplastic cells will be left behind, and the provider of the salve can then explain why the recurrence or metastasis of your cancer despite its apparent removal by the product is not their fault. Probably chemicals in the water or something.

The promoters of Neoplasene acknowledge, while downplaying, the risk of tissue damage from topical use of their product. They say you should “expect a wound to manage. It size will be in proportion to the extent of the tumor and the amount of Neoplasene compound applied…expect some scarring.”(1) The relevance of their earlier claim that “bloodroot chemicals and Neoplasene are simply not escharotics. They do not burn flesh” isn’t entirely clear, since they seem to be arguing that causing tissue to die and slough off leaving a bloody great hole is fine, so long as it’s through some mechanism other than chemical burn. Hmm.

The FDA has actually gone so far as to ban importation and marketing of bloodroot and other escharotics for cancer treatment, an all-too-rare example of government challenging “Big CAM” which further illustrates how frightening these products are(2). And yet these products are easily found on the Internet and used by a depressingly large number of CAM-oriented veterinarians, likely with a genuine belief that they are curing cancer through a miraculous means ignored by the corrupt and blind medical-industrial complex. I can’t say whether the active use and promotion of such products in the veterinary field, free from government sanction, is due to a loophole in the law or just the fact that the Hydra has many more heads than the FDA has paid investigators.

The only FDA-approved use of a bloodroot derivative, sanguinarine in dentifrice, is no longer popular as it proved to be a significant risk factor for leukoplakia, a potentially pre-cancerous disease(6). And while removal of low-risk, superficial skin tumors can be accomplished with escharotics, there are safer and more effective methods. Far from being a “wonder drug,” these products are an inappropriate and dangerous substitute for real scientific diagnosis and therapy of cancer. And contrary to the nonsense about the venality and blindness of the “cancer industry” and their own great insight, the promoters of Neoplasene are simply the latest head of the corrosive hydra that is bloodroot derivative cancer salves.

1. Fox, T.S. Discussion of and clinical guide for: the treatment of neoplasm, proud flesh and warts with sanguinarine and related isoquinoline alkaloids. Buck Mountain Botanicals, Inc., www.neoplasene.net, 2008.

2. Barrett, S. Don’t use corrosive cancer salves (escharotics); Quackwatch. www.quackwatch.org, 2009.

3. McDaniel, S., Goldman, G.D, Consequences of using escharotic agents as primary treatment for nonmelanoma skin cancer. Arch of Dermatol 2002; 138:1593-1596.

4. Moran, AM., Helm, K.F. Histopathologic findings and diagnostic difficulties posed with use of escharotic agents for treatment of skin lesions: a case report and review of the literature. J Cutan Pathol 2008; 35:404-406.

5. Ahmad, N., et al. Differential antiproliferative and apoptotic response of sanguinarine for cancer cells versus normal cells. Clin Cancer Res 2000; 6:1524-1528.

6. Mascarenhas, A.K., Allen, C.M., Moeschberger, M.L., The association between Viadent use and oral leukoplakia-results of a matched case-control study. J Public Health Dent 2002; 62:158-162.

Posted in Miscellaneous CAVM | 89 Comments

Screening Tests-Scientific Ambiguity or CAM Certainty

Posted on July 2, 2009 by skeptvet

One of my favorite encounters with CAM was when a woman brought an old golden retriever to see me because her energy practitioner told her she had detected leukemia, a kind of white blood cell cancer. Though the pet had no signs of illness at all, I ran a number of tests that failed to show any evidence of leukemia. A year later, the pet came back with a slight cough, and again the energy practitioner had told the owner there was cancer, probably in the lung this time. No such cancer appeared on x-rays, and the cough went away when the dog was treated for a bacterial upper respiratory infection. I asked the owner what had happened with the lymphoma that was previously “diagnosed” by her alternative provider. It turns out, not only was the energy practitioner not mistaken, she had apparently diagnosed lymphoma that was undetectable to the scientific methods I used and then cured it with homeopathy and manipulation of the patient’s energy.

Now this is fun all by itself. The quack will predict that an old golden retriever has cancer every year. Whenever the prediction is wrong, the energy healer will get credit for preventing the disease. But, sooner or later, the dog probably will get cancer, since it is a common disease in the aged and in that breed. When that happens, she’ll get credit for predicting it, and probably for palliating its symptoms and delaying the course. How do you get a racket like that?!

But, more seriously, this raises the question of how decide what screening tests to run in a given patient. Running bloodwork to look for leukemia in a symptom-free animal is pointless. The disease isn’t common, and it’s usually rapidly progressive so it makes the patient sick pretty fast. Testing clinically normal animals won’t likely find any leukemia cases, and it also won’t guarantee that the animals we test won’t get leukemia next week. It’s probably a harmless waste of $45 since the risk from drawing a blood sample is negligible, but it’s still unnecessary.

It is generally of questionable value to run screening tests blindly in apparently healthy animals. A study in Germany1 looked at bloodwork taken prior to anesthesia in over 1500 dogs and found that “the changes revealed by pre-operative screening were usually of little clinical relevance and did not prompt major changes to the anesthetic technique…In dogs, pre-anesthetic laboratory examination is unlikely to yield additional important information if no potential problems are identified in the history and on physical examination.” The study did show, however, that there were some “abnormal” results, and if those results led to delay in surgical treatment or to unnecessary diagnostics, then there could potentially be a cost to such screening.

In fact, sometimes the costs of tests that are not indicated by some specific clinical suspicion can be quite high. A recent study in the Annals of Family Medicine, covered in more detail on the Science-Based Medicine blog, found that the cumulative risk of undergoing unnecessary invasive diagnostic tests as a result of false positive results in several common screening tests for cancer was 29% in men and 22% in women over 3 years. These people had to cope with the anxiety of thinking they might have cancer, and with the risks of invasive diagnostic tests, when in fact the screening test was wrong. Harriet Hall has done a fine job of illustrating the same problem with screening asymptomatic patients in her discussion of prostate cancer and the PSA test. As with all things in the real world, benefits come with risks, and an appropriate balance between the two comes only from careful study and constant re-examination and revision of clinical practices.

Certainly screening tests, properly used, can save lives. But such tests are seldom as definitive as the public tends to think, and they are not without their risks. At least, in scientific medicine, an effort is made to determine when such tests are indicated, when their benefits outweigh their costs. In CAM, this is rarely the case. Chiropractic booths offering free spinal screenings are ubiquitous at county fairs, farmer‘s markets and other such venues, and shockingly every single person who gets “tested” turns out to have something that needs fixing. CAM practitioners are remarkable in their ability to find problems in apparently healthy patients. But as the anecdote I started with illustrates, they have some advantages over science-based medicine when it comes to such screening tests.

If you apply a CAM test to a healthy patient and find a subluxation, unbalanced Ch’i,
or some other result that no one else can confirm or deny, you may create some anxiety, and you will very likely expose the patient to the expense, and sometimes risk of treatment. But ultimately you can do whatever magic you do, declare the patient cured and the follow-up test results normal, and your client will likely thank you. You will certainly never have to face the awkward situation of not being able to find a lesion, and having the patient of pet owner decide you must be incompetent because they “know” something is wrong. And you will never have to agonize over whether running the test in the first place will do more harm than good, or whether false positive results might lead you to perform ultimately unnecessary diagnostics or treatments. And, as I’ve suggested before, you will have the advantage of a satisfyingly simply and clear narrative to offer, with no uncertainties. Yet another example of how CAM practitioners avoid the whole unpleasant issue of truth and fiction, and manage to make clients happy and themselves a nice living without all the bother of the constant questioning, self-doubt, and paradigm revision of real medicine.

1. Alef, M.,von Praun, F., Oechtering, G. Is routine pre-anesthetic haematological and biochemical screening justified in dogs? Vet Anesth Anal 2008; 35:132-140.

Posted in General | 4 Comments

The Evidence-Based Veterinary Medicine Conundrum

Posted on June 29, 2009 by skeptvet

The Evidence-Based Veterinary Medicine EBVM Conundrum

“Dr. X said that one of his main purposes when discussing EBM/EBVM at meetings is to get students/practitioners to question their decisions (i.e., to be less certain about decisions they make). This invariably results in “push back” from some attendees, because they go to meetings in hopes of coming away with answers/information; not more doubt and indecision. In human medicine, they do not have that problem. Once a physician’s misled belief in old stereotypic (non-evidentiary) information can be torn down, they can readily be remolded along EBM lines because there is plenty of valid EBM results published. On the other hand, there is a paucity of hard-core EBVM studies in the literature, and without significant funding this trend will continue in the foreseeable future. However, that should not diminish the effort… to get students and practitioners to understand that what they learn and later practice as practitioners is based on this paucity, to factor that into their decision processes, and to demand more valid studies based on the principles of EBM.

Another point made was that students, in particular, have the misguided belief that consensus is evidence. This belief needs to be dispelled.”

The above statement was made in the context of developing projects and goals for an organization striving to promote evidence-based medicine within the veterinary field. It struck me as identifying a key problem for those of us in the field trying to change the culture of veterinary medicine to be more focused on scientific, evidence-based medicine EBM) and less on the “art” of medicine, by which we usually mean the following of hunches and intuition by doctors.

Of course, the first step towards recognizing the values of EBM is acknowledging the limitations of our own abilities to assess our patients’ clinical problems and responses to our interventions. This is challenging enough as it directly threatens our sense of knowledge and competence. Doctors often caricature EBM as a painting-by-numbers approach to medicine, where the doctor is a mere robot following the pre-programmed algorithms produced by some faceless research bureaucracy. This image speaks to the depths of the fear clinicians have about acknowledging the unreliability of their own judgment in the face of the vast body of information that constitutes modern medical knowledge and the dazzlingly complex organisms that are our patients.

I believe this fear is unfounded, as the need for and value of intelligent, talented, and hard-working people is not diminished by EBM. It is simply a tool that replaces our best guess with real information. But the fear is understandable and powerful, and must be addressed if EBM is to make any headway among veterinarians.

But the EBVM Conundrum speaks to a problem that lies in wait for us after we have faced the already daunting task of instilling a greater sense of skepticism about our own wisdom and abilities in vets. What body of reliable science and evidence-based information are we to use as a replacement for our intuition and experience? There can, of course, never be enough good clinical data, and some level of uncertainty will always remain to be bridged by individual judgment. But in veterinary medicine, we are particularly blighted by the lack of well-designed and well-conducted clinical research. This is primarily an economic problem, though the culture of veterinary medicine plays a role.

Funding such research often requires the deep pockets of industry or government. And while industry does support a lot of veterinary research, the profits to be made are miniscule compared to those in the human medical field. And industry money doesn’t come without an agenda which can influence the direction and results of research. Even with rigorous controls and the best of intentions, it has been clearly demonstrated that the source of funding has a consistent and significant impact on the outcome of clinical studies.

And the political climate has long been unhealthy for government sponsorship of independent research even in human medicine. Veterinary medicine cannot expect much public sector support of such research except in those areas that are, or can be made to seem, directly relevant to human health concerns.

The news is not all bad, of course. Some good quality veterinary clinical and basic research is done and published, funded by academia, private foundations, industry, and the others. And, with a wealth of necessary caveats, research already done concerning human health issues can provide some useful guidelines. At the least, such data can help us be wise in how we use the limited resources we have. If decades of extensive research in human medicine have revealed nothing of value in prima facie unlikely therapies such as homeopathy, therapeutic touch, acupuncture, and the like, we would be smart to take the lesson and not spend too much effort and money demonstrating the comparable lack of utility for such methods in veterinary patients.

There are many individual veterinarians, and some institutions with veterinary medicine, that see the medical and economic benefits and the practical and philosophical, and ethical value of making veterinary medicine a truly evidence-based, scientific enterprise. And these agents are contributing to the realization of this goal despite the obstacles I’ve discussed. As the opening statement points out, changing the culture among veterinarians to be more accepting of our own limitations and of the need for the tool of EBM is necessary part of the process of developing the solid, evidence-based guidelines clinicians need. And identifying such problems as the EBVM Conundrum improves our ability to plan how best to move the veterinary medical field in this direction.

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The Science of Fear:Why We Fear the Things We Shouldn’t by Daniel Gardner

Posted on June 28, 2009 by skeptvet

The Science of Fear: Why We Fear the Things We Shouldn’t-and Put Ourselves in Greater Danger by Daniel Gardner does an outstanding job of explaining and supporting the argument that our ability to assess risks is fundamentally flawed.

The basic thesis is that our brains developed in an evolutionary context that selected for heuristics, quick and dirty methods of assessing situations and establishing guidelines for responding to the environment. These heuristics are hardwired into our brains (though Gardner refers to them collectively as Gut), and we tend to use them to rapidly judge how serious a potential risk is. Our higher reasoning abilities (which Gardner labels Head) can moderate these snap judgments by applying relevant facts and analysis, but more often our conscious reasoning merely manufactures rationalizations for what we’ve already decided.

The psychological literature on heuristics is vast, and though he uses shortcut labels such as Gut and Head, Gardner does a good job of defining and illustrating specific heuristics and tracing their discovery and the evidence for them. He then delves into factors that tend to prevent Head from doing a good job of moderating our emotional risk assessments. Inadequate education and familiarity with the relevant facts and with statistics, the influence of others’ opinions on our own, and the manipulation of our judgments through the media by government, industry, and lobbies, all of which use fear as a way to raise money and consciousness regardless of the statistical realities of the dangers they want us to care about.

He does an especially thorough job tracing the history of how unjustified popular fears of toxic chemicals in the environment and terrorism emerged and were promoted by the deliberate effort of those who cared more about influencing people’s behavior than about truth. I routinely have to disabuse people of the notion that their tap water or perfume or commercial dog food contains mysterious but horrible toxins responsible for their pet’s cancer. Gardner provides overwhelming evidence to show that environmental toxins are a negligible source of cancer, and yet we fear them out of proportion to their real danger. This leads us to underestimate the importance of much more significant risk factors such as age and obesity.

Gardner ends with what is for me the most salient chapter, entitled There’s Never Been a Better Time to Be Alive. Humans, and our pets, routinely live longer, healthier lives than at any time in history, and yet we are beset with anxieties about the food we eat, the water we drink, the air we breathe, the vaccines that protect us from the infectious we used to die of, and so many other sources of danger that we would be better off paying far less attention to. It is sad more than ironic that our ability to enjoy the unprecedented well-being our era provides is handicapped by our innate risk evaluation apparatus, which is still using rules that may have worked well enough on the savannah but which simply cannot cope with the subtleties and complexities of the modern world. Gardner provides some glimpses of hope, showing that while we cannot eliminate the errors in our risk assessments, we can moderate them significantly by virtue of deliberate, and difficult, application of thought and analysis.

From the point of view of scientific medicine, this book provides yet more evidence of the unreliability of our clinical judgments and intuitions compared with well-designed and conducted research. Science-based medicine acknowledges that we must have the courage and intellectual integrity to accept the inadequacy of our own judgments, of how things seem when confronted with clear evidence that they are wrong. CAM, in contrast, relies inherently on anecdote, tradition, and subjective evaluation for validation. And sadly, as unreliable as these clearly are, they are emotionally compelling. A nice companion to this book is Robert Burton’s On Being Certain: Believing You Are Right Even When You’re Not, which looks at the mechanisms of how we come to feel we know the truth of something. This feeling, like our assessment of truth and risk, is established at a level of thought we are not consciously aware of and then rationalized, often through obvious confabulation, by the conscious mind. The feeling of certain gets applied to our gut-level evaluation of the risk or benefit of something, and it then takes more effort than most of us are able or willing to make to discard the heuristic judgment in favor of the rational, and more likely correct one. But a commitment to doing the best for our pets requires that we try to make this effort so that we can provide them with the best care.

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From Science-Based Medicine Blog-Death and Rebirth of Vitalism

Posted on June 25, 2009 by skeptvet

Peter Lipsom has written a concise and insightful post at the Science-Based Medicine Blog, entitled The Death and Rebirth of Vitalism. It illustrates why the underlying philosophical position of faith-based medicine is unteneable. Magical entities, such as Ch’i in acupuncture, Innate Intelligence in chiropractic, Water Memory in homeopathy and so on, are required by CAM practices that cannot demonstrate plausible rationales by mainstream scientific methods. This contrasts with the Methodological Naturalism required by science, and the true philosophical naturalism and materialism many scientist accept as the truth about the nature of the universe.

As the comments that follow the post illustrate, pointing out the intellectual bankruptcy of the philosophy behind most CAM approaches can lead to resistence against science-based medicine even among scientists and people not otherwise sympathetic to CAM. This is at least partly because looking at the underlying philosophical and epistemelogical distinctions between science-based and faith-based medicine can lead to awkward questions about other faith-based beliefs.

The human mind is miraculous in its ability to hold contradictory ideas at the same time, so many scientists can go about their lives practicing methodological naturalism while believing in the eternal soul, reincarnation, or other non-material entities without trouble, so long as the conflict isn’t shoved in their faces. When it is, some attempt to work out acceptable philosophical compromises, such as Stephen Jay Gould’s Non-Overlapping Magisteria approach. Others simply choose faith over reason and most simply decide not to dwell on the issue. A few, think and read and meditate deeply about the controversy and elect to try and extend their professional naturalism into all areas of their lives. As far as I’m concerned, these are all fair and legitimate responses to a tough question.

But what is not legitimate is when the challenge to faith in areas outside of science is so threatening that scientists choose to let go of their methodological naturalism and embrace faith-based medicine uncritically. Not everyone cares to conduct difficult and complex investigations into the philosophical underpinnings of theri work or their personal life, and this isn’t by any means a requirement for a productive life in science or medicine. I happen to think it can enrich anyone’s life and work, but that may just be my personal intellectual tastes. However, when it comes to the material world, which includes the bodies and minds of our patients and the tools with which we treat them, there are right and wrong answers. Vitalism may stumble on the right answers by accident from time to time, but science and methodological nauralism consistently get the answers right far more often. To ignore this and cling to faith-based medical practices simply to avoid uncomfortable questions about other deeply held faith-based beliefs is intellectually dishonest and not in the best interests of our patients.

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Veterinary Vaccines-Fact and Fiction

Posted on June 24, 2009 by skeptvet

What Are Vaccines?
The principle behind vaccination is that small amounts of weakened or killed organisms that normally cause disease, or even just pieces of these organisms, are given to an animal. This stimulates the immune system to generate a protective immune response without an actual infection or illness.

The first experiments with vaccination in dogs were conducted by Louis Pasteur in 1884, but reliably safe and effective vaccinations for most disease were not routinely available until the 1950s or later. Since vaccination became commonplace, the incidence of rabies, distemper, parvovirus, and many other infectious diseases has decreased dramatically. Along with improvements in nutrition and the development of antibiotics, vaccines have been among the most successful medical interventions for reducing disease, suffering, and death in companion animals.

But like all effective medical treatments, vaccines are not without risks, and recently there has been an increase in concern about their safety. Fortunately, there has also been a great deal of research into the benefits and risks of vaccination, and this information can help veterinarians and pet owners to make appropriate decisions about the best way to safeguard their pets’ health.

Why Vaccinate?
There are many infectious diseases that affect dogs and cats. Some cause severe, life-threatening illness. Some cause mild symptoms that can resolve spontaneously or persist for years. And some, such as rabies, can cause disease in humans as well as our pets.

The most obvious benefit of vaccination is preventing illness in the individual given the vaccine. This is especially clear with vaccines that are highly effective at preventing potentially fatal infections, such as canine distemper, canine parvovirus, and feline panleukopenia. Even those vaccines that do not prevent illness can reduce the severity of symptoms, as in the cases of several upper respiratory viruses in cats.

A less well-know but very important benefit of vaccination is to prevent epidemics in a population of animals, through what is called herd immunity. If a large number of individuals are protected by vaccination, there are not enough susceptible animals to allow a disease to spread, and so even unvaccinated individuals are protected from infection. When vaccination rates drop, however, then a few isolated cases can turn into a widespread epidemic.

There have recently been outbreaks of measles and haemophilus influenza B among humans as a result of fewer people in some areas getting vaccinated for these diseases. And in 1994-1995 there was an epidemic of canine distemper in Finland, where the disease had previously been eliminated, largely because too few dogs were adequately vaccinated.

The proportion of the population that must be vaccinated for herd immunity to work depends on the prevalence of the disease, the effectiveness of the vaccine, and other factors, but in most cases more than 90% of individuals must be vaccinated for those who are not to be protected. So if even a few individuals do no receive adequate vaccination, an epidemic can potentially develop.

Finally, vaccination of pets can be important for the health of their owners and other humans. Human cases of rabies due to dog bites, which is nearly always fatal, were once a serious public health problem in the United States. Widespread vaccination of dogs has eliminated this threat, though it is still a serious risk for people, especially children, in countries where such vaccination is not available or utilized.

Do They Work?
For many serious diseases, vaccination is very effective. There is some variation between vaccines, but the efficacy for vaccination against canine distemper, canine parvovirus, rabies, feline panleukopenia, and feline leukemia is excellent, in some cases close to 100%. Other vaccines, such as those for feline herpes virus and feline calicivirus, may not prevent infection but may markedly reduce the symptoms the infected pet suffers. However, there are some vaccines that are considered only poorly effective and others for which not enough information exists to determine how well they work.

As already mentioned, herd immunity depends to some extent on how common the disease organism is in the environment, how effective the vaccine is, and what percentage of the population is vaccinated. Even for vaccines with weak efficacy, if most animals are vaccinated then epidemics are less likely. And even when a vaccine is very effective, if many unvaccinated individuals are present to spread the disease, epidemics can develop.

What, When, How Often?
When many of the common vaccines were introduced decades ago, there was limited information on how effectively they protected animals from disease and for how long. The common practice was to give vaccines for many different diseases routinely every year. Significant improvements in our understanding of how vaccination works to prevent disease has led to widespread abandonment of this practice. The precise vaccines to be given, when, and how often can only be determined on an individual basis, considering the exposure of the patient to specific diseases, the effectiveness and risks of available vaccines, and many other factors. Some general principles, however, are applicable to all individuals.

Puppies and kittens that nurse usually receive antibodies from their mothers. These antibodies offer some protection from infectious diseases, though how much protection and for which diseases depends on many variables and is very difficult to predict. These maternal antibodies, however, also interfere with the action of vaccines. As puppies and kittens mature, they gradually lose their maternal antibodies and, if vaccinated, develop their own. For most individuals and most diseases, maternal antibodies begin to decrease by 6-8 weeks of age and are effectively gone by 14-16 weeks of age. As the level of maternal antibodies decreases, the young animals are at more and more risk for contracting infections until they have produced sufficient protective antibodies of their own.

For this reason, young animals must receive a series of vaccinations between 6 and 16 weeks of age. Because it cannot be determined exactly how much protection each individual has from nursing or how long that protection lasts, a series approach to vaccination maximizes the development of the patient’s own antibodies and minimizes the risk of gaps in protection as the maternal antibody levels decline.

For adult animals, the vaccines that will best protect them depend on individual circumstances. Current recommendations divide vaccines into core and non-core categories. Core vaccines are those that protect against organisms which cause severe disease, are easily transmitted between animals, are widespread in the environment, and for which the vaccines are recognized as safe and highly effective. Non-core vaccines are those used for organisms that cause mild self-limiting disease, are not widespread or easily transmitted, or for which the vaccines are not highly effective or carry unacceptable risks. Non-core vaccines are still appropriate to use if warranted by circumstances, but unlike core vaccines are not generally recommended for all pets
Finally, a few vaccines are generally not recommended at all due to uncertainty about their safety or efficacy or other concerns.

It is generally recommended all animals receive core vaccines at regular intervals and only receive non-core vaccines if the individual’s circumstances suggest the benefit outweighs the risks. For dogs, most veterinarians consider core vaccines to be those against canine distemper, parvovirus, hepatitis, and rabies. For cats, feline panleukopenia, herpes virus, and calicivirus vaccines are generally consider core vaccines. There is some debate about whether rabies and feline leukemia vaccines should be considered core vaccines for cats, and this depends mostly on a given cat’s likelihood of exposure, age, and the local rabies vaccination laws.

How often to give vaccines to adult animals is a topic of vigorous debate. Differences in individual immune function, in vaccine efficacy and safety, in regional risk of exposure to specific diseases, in individual or breed predisposition to diseases and response to vaccines, and many other factors make it nearly impossible to make definitive and universal statements about how long a vaccine will protect a given patient. A broad consensus exists among veterinarians and researchers that the initial puppy or kitten series of core vaccinations and a booster one year later is appropriate for almost all animals. There is strong evidence that most core vaccines will provide adequate protection for most individuals if given at most every 3 years, and for some diseases protection likely lasts much longer. However, there is insufficient evidence for detailed and universal guidelines for most vaccines.

There is little research on vaccines in geriatric animals. Older pets do respond to vaccines with an appropriate increase in immunity, and they do not seem to be at an increased risk of dverse reactions from vaccines. There is no sound evidence to suggest that vaccination should be stopped at any particular age.

A general principle of medicine is that the benefit of a treatment should exceed the risk, so much of the discussion about how often to vaccinate and for which diseases centers on what is know about the risks of vaccination.

Are They Safe?
Like any potent medical therapy, vaccines can have unintended effects. Since vaccines are commonly given, often multiple times over many years, it can be difficult to decide if an illness is related to previous vaccination. In humans, there has been much concern about vaccination being responsible for autism in children, since the disease tends to emerge at about the time most children are vaccinated. Only after years of extensive research in thousands of children throughout the developed world has this theory been convincingly disproven. High quality research on this large a scale is rarely possible in veterinary medicine.

However, some good quality studies have been done to determine what adverse effects vaccines might cause, and how common and serious these are. Estimates vary, largely because it is often impossible to determine what the total population of dogs or cats is, what percentage of these have been vaccinated when and for what, and to gather other information necessary to accurately determine how common vaccine reactions really are. On the high end, estimates of total adverse vaccine reactions, provided by manufacturers based on pre-clinical testing, are on the order of 100 reactions per 10,000 vaccine doses given. Numbers based on research in actual pet populations are much lower, ranging from less than 1 reaction per 10,000 vaccines given up to 13 reactions per 10,000 doses given in dogs and 20 per 10,000 doses given in cats.

The most common by far are local or systemic hypersensitivity reactions, usually called allergic reactions. These account for 30-60% of adverse vaccine reactions. The vast majority of these reactions that are seen by a veterinarian resolve spontaneously or with minimal medical treatments. Many localized allergic reactions are thought to resolve without ever being noticed by the owner or reported to a veterinarian.

The risk of allergic reactions is not the same for all pets. Smaller dogs are at greater risk than larger dogs, and the risk increases the more vaccines are given at one time. Some research suggests certain breeds may be at higher risk than others, but other studies do not support this.

More serious adverse reactions are much rarer. A disease in which the immune system attacks the patient’s own red blood cells (IMHA) has been reported in one study to be associated with vaccination at a rate of 0.01 reactions per 10,000 doses, though a more recent study of the same disease found no association with vaccination. Other autoimmune diseases have been reported in specific breeds (such as hypertrophic osteodystrophy after canine distemper vaccine in Weimeraners and localized vasculitis in Dachshunds), but these are uncommon to rare and linked with specific genetic predispositions in affected dogs. It is also important to remember that these diseases can also be triggered by the very infections vaccines are used to prevent as well as medications, natural substances in food and in the environment, and anything that stimulates a response in the immune system of a predisposed animal.

The most widely known adverse vaccine reaction in animals is a rare type of cancer in cats known as Vaccine Associated Sarcoma (VAS). Identified by careful research in the early 1990s, this tumor has been linked to specific vaccines for rabies and feline leukemia. Similar tumors can occur spontaneously or in response to trauma, foreign bodies, local infections, and other things that stimulate the immune system. However, the risk of VAS is significantly increased by these vaccines, and it is suspected that the reason is certain ingredients, such as aluminum, that were added to the vaccines to increase their stimulation of an immune response. Estimates vary, but the most reliable figures suggest VAS occurs at a rate of 0.3-2 tumors per 10,000 vaccine doses given.

The discovery of this tumor stimulated much concern about the safety of vaccinations. While it is quite rare, great efforts have been made to reduce the incidence of VAS by developing new vaccines and researching the safest way to use these vaccines to protect cats from infectious disease while minimize such reactions. The debate and research has even spread beyond feline leukemia and rabies and stimulated a significant change in vaccination practices generally for both dogs and cats.

Finally, it is vital not to forget that the risks of vaccination must be considered in light of the benefits. For most core vaccines, the diseases they protect against represent a far greater threat to the health of our pets than the vaccines.

Vaccine Myths
While careful evaluation of the risks and benefits of vaccination, and cautious and thoughtful use of this potent medical tool, is absolutely appropriate, irrational fear of vaccines has unfortunately led to the spread of many myths about them. Some of the concerns raised about vaccines used in humans have been extended to companion animal vaccination, despite the evidence that many of these concerns are unfounded. And it has become all too common to identify vaccination as a possible, or even probable cause for any disease that is not yet completely understood. While unknown and unpredictable risks are always possible, careful scientific research has discovered even such rare adverse effects as Vaccine Associated Sarcomas, and many of the purported negative effects of vaccines are merely wild speculations with no basis in fact.

The most common myth about vaccines is that they are not necessary since the diseases they protect against are rare. The diseases for which we have core vaccines in dogs and cats all continue to exist in the population as a threat to unvaccinated individuals. And in cases where vaccine rates have dropped due to this misconception, epidemics of some of these diseases have occurred.

Another common concern are the immune system diseases caused by vaccines. Though auto-immune diseases such as IMHA may be associated with vaccination, this has not been conclusively demonstrated. And if vaccines do precipitate such diseases, so do infectious organisms, natural substances in food, and many other possible environmental factors. These conditions are uncommon, and any risk of them posed by vaccination is undoubtedly outweighed by the protection the vaccines offer against serious infectious diseases.

Some vaccinated animals have been shown to have antibodies against normal proteins in their own bodies, including the thyroid gland and the kidneys, and this has stimulated speculation that diseases in these organs may be the result of vaccination. However, the relationship between vaccination and such antibody formation is inconsistent, and no actual immune-mediated disease has ever been shown to result from the presence of vaccine-induced auto-antibodies.

Much publicity has been generated by concerns over “toxins” in vaccines. Thimerosal, aluminum, formaldehyde, anti-freeze, and many other substances have been claimed to be present in vaccines and to be harmful to vaccinated people or animals. Some of these substances are present in minute quantities in vaccines, though others are not. The primary misconception that creates unjustified fear about these ingredients is the notion that substances are inherently either toxic or safe. Water and oxygen can be poisonous, even fatal in high enough amounts even though they are vital for life. And while large amounts of some vaccine ingredients can be dangerous, the minute quantities in vaccines have never been shown to be harmful.

Preservative such as thimerosal and formaldehyde prevent bacterial and fungal contamination of vaccines, and research in humans has shown they do not cause harm at the amounts given in vaccines. Aluminum adjuvant has not been associated with significant risk in humans. In cats, aluminum is believed to increase the risk of VAS, and non-adjuvanted vaccines are now recommended in this species.

Some people have expressed concern over the number of vaccines given in the puppy or kitten series, or over the lifetime of the pet, and have put forward the notion that so many vaccine antigens (the part of the disease-causing organism that the immune system reacts to) may “overload” the immune system, causing health problems. However, the number of foreign antigens animals are exposed to in vaccines is far less than what they encounter in the course of everyday life. We and our pets ingest and inhale antigens continuously, and we are exposed to more through wounds, insect bites, and many other sources. The relative contribution of vaccines to the total antigen exposure of any individual is miniscule. And the capacity of the immune system to generate a response to possible disease-causing organisms is so vast that even the extensive vaccination schedule recommended for children has been calculated to require only about 0.01% of this capacity.

It is commonly supposed that vaccines should be dosed by body weight the way most drugs are in veterinary patients. This is a misconception. While most drugs work by being distributed throughout the body and acting in proportion to their concentration in the blood or tissues, vaccines stimulate the immune system locally where they are administered. The Minimum Immunizing Dose (MID) is the amount of antigen necessary to stimulate a protective immune response. This varies by species and vaccine, but it has little relationship to body size. Horses only receive twice as much rabies vaccine as dogs, and elephants only twice as much as horses. The difference in size between individuals within a species is too small to affect the MID, and if only partial doses of vaccine are given there is a real risk on not triggering an adequate response to protect the patient.

Finally, there has been some talk of a vague, generalized illness attributed to vaccination and sometimes referred to as “vaccinosis.” There is no consistent definition of this supposed illness, but it is generally described with a series of anecdotes about animals that were vaccinated and became ill sometime afterwards, with no explanation of why the vaccine should be considered responsible for the illness. There is no evidence that “vaccinosis” is a real clinical entity or that the practice of blaming any illness of unknown cause on vaccines is justified.

A large-scale study of over 4000 dogs completed by the Animal Health trust in the UK found no association between vaccination and any specific illness, or ill-health in general, in the 3 months following the vaccination. Careful and controlled research is needed to document any adverse reaction to vaccines, and without such research there is no basis for concluding that vaccines cause disease beyond the uncommon, and rarely serious reactions already identified.

Alternatives to Vaccination?
The most commonly chosen alternative to vaccination is simply to not vaccinate. Unfortunately, this replaces the very small risks from vaccines with a much greater risk of disease for the unprotected individual and for other animals and even humans. While it is true that natural exposure to infectious organisms can stimulate a protective immunity, this comes with a risk of disease that is much more dangerous than the adverse effects of vaccines.

It has been suggested that proper nutrition in general, or special diets and dietary restrictions, can prevent disease and make vaccination unnecessary. While the immune system does function poorly in malnourished animals, those individuals who are fed adequate amounts of a balanced diet and are in good general health have normal immune function. There is no evidence that special diets or dietary limitations can improve on this normal function, and diet is certainly no substitute for appropriate vaccination.

Some alternative products claim to provide protection from disease without the risks of vaccines. The most common of these is the homeopathic nosode. Nosodes are prepared by extreme dilution of blood, urine, pus, or some other substance associated with the infection the preparation is supposed to prevent. Like all homeopathic preparations, nosodes do not contain any of the original ingredients due to the extensive dilution, so they consist only of the vehicle used, usually water or alcohol. Despite the lack of a plausible scientific rationale behind nosodes, some clinical studies of their effectiveness have been done, and these have shown them to be ineffective at preventing canine parvovirus and other infectious diseases.

Finally, blood antibody titers are sometimes recommended as an alternative to vaccination. This is a complex subject, and it is not possible to make definitive, universal recommendations about when titer testing is helpful. For some diseases, such as canine parvovirus, rabies, and feline panleukopenia, high antibody titer levels have been shown to reliably predict resistance to infection. However, due to other elements of the immune system which titers do not measure, animals with low titers to these diseases may still be protected from infection.

For other diseases, titers do not reliably predict whether the patient is resistant to the disease or not. And the predictive value of antibody levels also depends on how common the disease is in the population, so for an uncommon disease a negative titer is more likely to be an error, which makes deciding which individuals need vaccination based on their titer unreliable. Titers are useful in certain circumstances, but they are not appropriate as a routine alternative to vaccination for the general population.

Summary

? Vaccination is an important tool that has reduced the risk and harm of infectious disease dramatically in companion animals.

? While they vary in their efficacy, most commonly used vaccines are highly effective at preventing infection or reducing the symptoms of disease.

? Puppies and kittens need a series of vaccinations between 6 and 16 weeks to develop their own protective immunity as the maternal antibodies they get from nursing disappear.

? Which vaccines need to be given to adult animals, and how often, should be decided on the basis of unique individual circumstances and risk factors.

? Vaccines are generally very safe, but some adverse effects do occur. These are uncommon and usually easily treated, but more serious effects are possible, and the benefits of vaccination should always be weighed against the risks for each patient.

? The fears that vaccines contain harmful toxins, that they overwhelm the immune system, or that they routinely cause serious illness are unfounded and not supported by any real evidence.

References and More Information
American Animal Hospital Association Canine Vaccine Task Force. Canine vaccine guidelines (rev). 2006. Available at http://secure.aahanet.org/eweb/dynamicpage.aspx?site=resources&webcode=CanineVaccineGuidelines .

American Veterinary Medical Association. What you should know about vaccinations. 2008. Available at www.avma.org .

Day, M.J. Vaccine side effects: Fact and fiction. Vet Microbiol 2006; 117:51-58.

De Verdier K, Ohagen P, Alenius S. No effect of a homeopathic preparation on neonatal calf diarrhoea in a randomised double-blind, placebo-controlled clinical trial. Acta Vet Scand 2003; 44:97-101.

Edwards, D.S., Henley, W.E., Wood, J.L. Vaccination and ill-health in dogs: a lack of temporal association and evidence of equivalence. Animal Health Trust 2004. Available at http://www.future-of-vaccination.co.uk/animal-health-survey.asp .

Ek-Kommonen, C., et al. Outbreak of canine distemper in vaccinated dogs in Finland. Vet Rec 1997; 141:380-383.

Feline Vaccine Advisory Panel, American Association of Feline Practitioners. JAVMA 2006; 229:1405-1441.

Frana, T.S., Clough, N.E., Gatewood, D.M., Rupprecht, C.E. Postmarketing surveillance of rabies vaccines for dogs to evaluate safety and efficacy. JAVMA 2008; 232:1000-1002.

Klingborg, D.J., et al AVMA Council on Biologic and Therapeutic Agents’ report on cat and dog vaccines. JAVMA 2002; 221:1401-1407.

National Office of Animal Health. Vaccination of companion animals: Briefing Document No. 10. Available at www.noah.co.uk .

Gobar, G.M, Kass, P.H. World wide web survey of vaccination practices, postvaccinal reactions, and vaccine site-associated sarcomas in cats. JAVMA 220; 1477-1482

Grosenbaugh, D.A., et al. Comparison of the safety and efficacy of a recombinant feline leukemia virus (FeLV) vaccine delivered transdermally and an inactivated FeLV vaccine delivered subcutaneously. Vet Ther 2004; 5:258-262.

Holmes MA, Cockcroft PD, Booth CE, Heath MF. Controlled clinical trial of the effect of a homoeopathic nosode on the somatic cell counts in the milk of clinically normal dairy cows. Vet Rec 2005; 156:565-567.

Larson L., Wynn S., and Schultz R.D. A Canine Parvovirus Nosode Study. Proceedings of the Second Annual Midwest Holistic Veterinary Conference 1996.

Legendre, A.M., et al. Comparison of the efficacy of three commercial feline leukemia virus vaccines in a natural challenge exposure. JAVMA 1991; 199:1456-1462.

Moore, G.E. Vaccine reactions today and tomorrow: When vaccines do too much. Proceedings of the American College of Veterinary Internal Medicine 2003.

Moore, G.E. A perspective on vaccine guidelines and titer tests for dogs. JAVMA 2004; 224:200-203.

Moore, G.E., et al. Adverse events diagnosed within three days of vaccine administration in dogs. JAVMA 2005; 227:1102-1108.

Moore, G.E., et al. Adverse events after vaccine administration in cats: 2,560 cases (2002-2005). JAVMA 2007; 231:94-100.

Offit, P.A., Jew, R. K. Addressing parents’ concerns: Do vaccines contain harmful preservatives, adjuvants, additives, or residuals? Pediatrics 2003; 112:1394-1401.

Offit, P.A., Bell, L. M. Vaccine Concerns. Chapter 15 of Vaccines: What You Should Know 2003. Available at www.immunize.org .

Rikula, U. K. Canine distemper in Finland- Vaccination and epidemiology. Academic dissertation 2008. Available at http://www.evira.fi/uploads/WebShopFiles/1207123242400.pdf .

Roush, S.W, Murphy, T.V. Historical comparisons of morbidity and mortality for vaccine-preventable diseases in the United States. JAMA 2007; 298:2155-2163.

Scott-Moncrieff, J.C., et al. Evaluation of antithyroglobulin antibodies after routine vaccination in pet and research dogs. JAVMA 2002; 221:515-521.

Veterinary Prducts Committee Working Group on Feline and Canine Vaccination, Dept. for Environment, Food & Rural Affairs 2001. Available at http://www.noah.co.uk/papers/vpc-catdogvetsurv.pdf .

Wolf, A.M. Vaccines, viruses, vaccinosarcoma-Truth or fiction. ProceedingsAtlantic Coast Veterinary Conference 2002.

© Brennen McKenzie, 2009
http://www.skeptvet.com
http://skeptvet.com/Blog

Posted in Vaccines | 29 Comments

Government Fails to Protect People from Harmful CAM

Posted on June 23, 2009 by skeptvet

A healthy women, told by her chiropractor she needed her subluxations treated by forceful manipulation of her neck to “improve her health and wellness” ended up a quadraplegic. She and others hurt by chiropractors in Canada have filed a class-action lawsuit, not only against the chiropractors but against the state government. The government, of course, is trying to get itself out of the lawsuit, which alleges that it bears some responsibility for the harm done to healthy people by chiropractors.

While it is no surprise to anyone that governments set health policy based on money and influence rather than science, it has always disappointed me how easily ineffective, unproven, and even potentially dangerous medical treatments get the imprimatur of the state. When I begin to tell people about the lack of evidence for benefit from chiropractic manipulations, the second objection they make after reporting some anecdotes and testimonials is that it is licensed by the government so how could it not work? It’s difficult to explain to them simply why money and influence trumps science, and why our faith in government regulation of medicine is not justified when it comes to CAM. By not insisting on real evidence of safety and efficacy for all medical therapies, government not only contributes to the harm CAM does to its citizens, but it undermines its own credibility as guardian of the public health.

A lawsuit like this, though I doubt it will be successful, makes a stark and important point. People rely on their government to protect them from harmful and useless treatments when they are suffering and vulnerable to peddlers of snake oil. Because mainstream medicine has been so successful in the last 200 years, people are accustomed to trusting that anyone who calls themselves a doctor knows what they are about. Otherwise, wouldn’t the government step in and stop them? Unfortunately, the economic power of the CAM lobby and the zeal of true believers in government, like our own Sen. Tom Harkin here in the U.S., interfere with the mechanisms the government would normally use to protect people from dangerous treatments.

Ironically, mainstream scientific medicine, and even the quintessential bogeyman of Big Pharma, is heavily scrutinized and regulated, and it is a costly and time-consuming process to get a treatment that actually works approved. And when uncommon problems are identified, by virtue of post-marketing surveillance mechanisms the government requires, instead of seeing this as evidence for the success of the science and the system, CAM proponents use it as more evidence that their own therapies are safer alternatives.

Undoubtedly, less harm is reported subsequent to CAM treatments simply because no one is watching or keeping track. What’s The Harm, Victims of Chiropractic Abuse, and other private groups try to warn people of the dangers, but many of the dangers are not even known, and such small advocacy groups cannot match the resources and influence of government. I hope the government of Alberta is made to acknowledge it has abdicated its responsibility to its citizens to protect them from dangerous medical treatments, though I am not optimistic. And here in the U.S., President Obama has promised to see that science resumes “it’s rightful place” in the setting of public policy. He will undoubtedly have a very hard time keeping that promise. But for the sake of all those who the government might save from the harm of untested treatments, I hope he can.

 

Posted in Law, Regulation, and Politics | 2 Comments