Raw Pet Foods & The Death of Expertise

One of the more enlightening, and terrifying, books to come out in the last 5 years is Tom Nichols’ The Death of Expertise. In clear prose, with cogent argument and substantiating evidence, the author makes the case that the proliferation of misconceptions, delusions, and bizarrely wrong beliefs about the world in every domain, from science to politics, reflects powerful and pervasive elements of American culture. Access to accurate information is easier than ever, yet misinformation thrives. The problem is not that the truth isn’t available to us, it’s that we actively reject it. In Nichols’ words,

These are dangerous times. Never have so many people had so much access to so much knowledge and yet have been so resistant to learning anything.

[The real problem is] we’re proud of not knowing things. Americans have reached a point where ignorance, especially of anything related to public policy, is an actual virtue. To reject the advice of experts is to assert autonomy, a way for Americans to insulate their increasingly fragile egos from ever being told they’re wrong about anything…It is a new Declaration of Independence: No longer do we hold these truths to be self-evident, we hold all truths to be self-evident, even the ones that aren’t true. All things are knowable and every opinion on any subject is as good as any other.

This is a phenomenon I have wrestled with for many years in my efforts to promote science-based veterinary medicine. Giving people facts and evidence is not sufficient because, as Nichols says, “When feelings matter more than rationality or facts, education is a doomed enterprise.” Believers and promoters of pseudoscience in medicine are armored by feelings and conviction against any inconvenient facts or evidence. And the average pet owner is at a disadvantage since they can’t always judge the relative merits of scientific claims or data for themselves, and they are left deciding which source of information to trust or, in the worst case, simply choosing to believe the claim that best fits their pre-existing world view.

A recent survey of pet owners investigating attitudes about raw and commercial coked pet diets illustrates this death of expertise quite starkly. 

Empert-Gallegos A, Hill S, Yam PS. Insights into dog owner perspectives on risks, benefits, and nutritional value of raw diets compared to commercial cooked dietsPeerJ. 2020;8:e10383. doi:10.7717/peerj.10383

The facts are clear and not seriously questioned by actual experts, including veterinary nutritionists and most mainstream veterinarians. Raw diets have no proven benefits and any claimed for them are based on pure anecdote or theory. Raw diets do, however, have clearly established risks, including causing potentially deadly food-borne illness and often being nutritionally inadequate. The evidence to support these facts can be found in the many posts I have written on this subject.

Unfortunately, these facts are inconvenient for people who choose to feed such diets, and their reaction to being confronted with them is simply to redefine themselves as the “real experts.” Among owners feeding conventional cooked diets, 78% felt their veterinarian had a high level of knowledge about nutrition (4 or 5 on a 5-point scale). In this age when anyone can declare themselves an expert based on an internet search or some other informal way of investigating a subject, 65% of owners feeding cooked diets rated themselves as highly knowledgeable about pet nutrition, at the same level of knowledge, in fact, as their veterinarian. It is pretty unlikely that a majority of these owners have degrees in animal health or have taken formal instruction in animal nutrition, so this is a pretty unreasonable assessment. But it gets worse.

Of the raw feeders, 86% declared themselves highly knowledgeable (4-5 out of 5) while only 45% of them credited their veterinarian with this level of expertise. Raw feeders are no more likely than other pet owners to have degrees in animal health or nutrition, but they do have stronger feelings about the subject and are more likely to have investigated web sites or books for the general public making nutrition claims. These owners, whose beliefs are the least consistent with the facts, have the greatest confidence in their own knowledge and the least confidence in the expertise of actual veterinary professionals. This is unlikely to lead to good feeding choices or the best outcomes for pets.

The irrationality behind this false sense of expertise is illustrated by other findings in this study. Raw feeders rated commercial and homemade raw diets as more nutritious and safer than commercial cooked diets, both beliefs inconsistent with the facts. These owners likely imagine they have some special knowledge or insight into the “real truth” about pet food that owners feeding cooked diets, or even veterinarians, lack. This insight was not evidence, however, in their free-text answers to questions about the reasons for feeding raw diets, which included many vague references to unproven health benefits and terms consistent with unscientific beliefs about nutrition, such as “natural,” “processed,” “chemicals” and so on. 

These owners clearly believe strongly that raw diets are healthier than cooked diets, but the strength of this belief, and the confidence in their own expertise in the subject, are based on misinformation and falsehoods. As Mulder would say, “The Truth is Out There,” along with the evidence to support it. But truth and facts aren’t nearly as effective at generating belief as the vapid handwaving and passionate proselytizing of raw food advocates. Ultimately, if people choose belief and feelings over science and expertise, they can maintain any belief regardless of the facts. Raw feeding, like so many other alternative veterinary practices, is just one more illustration of this pervasive and malignant cultural problem.

Posted in Nutrition | 1 Comment

Neutering and Aggression in Dogs

I have written extensively about the positive and negative effects of neutering dogs for many years. This is an area of great controversy and rapidly advancing research. There is no simple relationship between neutering or age at neutering and health. Neutering itself changes many aspects of an animal’s physiology, and some of these changes have beneficial effects while others have harmful effects. The breed and genetic makeup of an animal, the age at which it is neutered, the environment in which it lives, and many other factors all work together to influence health, and the simplistic notion that neutering is “good” or “bad” for all dogs is simply untrue.

I recently found an interesting study examining the relationship between neutering and aggressive behavior in dogs which illustrates this complexity.

Farhoody P, Mallawaarachchi I, Tarwater PM, Serpell JA, Duffy DL, Zink C. Aggression toward Familiar People, Strangers, and Conspecifics in Gonadectomized and Intact DogsFront Vet Sci. 2018;5:18. 

It has traditionally been assumed, by dog owners and many veterinarians, that neutering reduces aggression, at least in males. The research to date, however, has been far from clear. Some studies support this idea, others show no effect of neutering on aggressive behavior, and some find neutering can increase aggression. The sex of the dog and the age at which it is neutered all play a role as well. While there likely is some relationship between neuter status and behavior, including aggression, behavior is a tremendously complex product of a multitude of factors, and what relationships there is between this and neutering is unlikely to be simple or universal.

This study approached the question in an interesting way. By looking through data collected in the past on thousands of animals using a behavioral questionnaire that has been widely used and is well-validated, they selected a huge population of dogs for which the details of neutering and also of aggressive behavior patterns were known. This has the advantage of a large enough s ample size to allow robust statistical comparisons. However, such a retrospective design has a lot of limitations, including the inability to acquire and consider relevant information that might not have been recorded in the survey and potential bias in the population of animals included. This was not a study population selected in an unbiased fashion specifically for the project but a database of voluntary responses to an online behavior questionnaire. People likely to fill out such a questionnaire, and their dogs, are likely different in meaningful ways from people not choosing to do so.

The researchers used mathematical techniques to compare the rates of different types of aggressive behavior (directed towards familiar people, directed towards unfamiliar people, and directed towards other dogs) with information about neutering and other factors (sex, age, weight, etc.). When all of the variables considered in the study were included in the model, no relationship was found between neutering at any age and any type of aggression.

When a different model was used to consider only a limited subset of the variables considered, the only relationship found was a small increase in the odds of aggression towards strangers among dogs neutered between 7 and 12 months of age.

The real-world significance of these findings is not completely clear. The authors emphasize that the results don’t support the assumption that neutering reduces aggression since neutered dogs were not significantly less aggressive than intact dogs. Of course, the other way to frame the findings is that the results suggest neutering has no effect on aggression either way, so aggressive behavior shouldn’t be a major consideration in decisions about neutering. The finding that aggression towards strangers was more common in dogs neutered between 7 and 12 months of age is likely a statistical fluke, and though the authors propose some possible hypotheses for it, they admit it is difficult to explain.

The study did not consider breed, which likely plays a significant role in some kinds of aggression based on previous studies. It also did not consider owner factors, which clearly influence both the behavior and the neuter status of dogs. It has always been an open question whether aggression by certain breeds or by intact dogs might have more to do with the owners who choose the breed and decide whether or not to neuter than with the neutering or breed per se. This study does not help clarify that question.

Overall, this is an interesting but not definitive contribution to the subject of how neutering might affect behavior. It undermines the traditional and simplistic notion that neutering prevents aggression, and it suggests that there are many factors influencing aggressive behavior in dogs and neutering is only one and likely not the most important.

Posted in General | 2 Comments

Five Most Dangerous Alternative Therapies for Pets- From SkeptVet TV

Posted in SkeptVet TV | 7 Comments

New Study Shows No Benefit from Acupuncture for Dogs with Arthritis

I have written extensively over the years about acupuncture, and my investigations have ranged from the laboratory animal and human literature to veterinary clinical studies, to completing a certification in medical acupuncture and treating patients in my clinic. Through all of this, I have found little to change my basic views of acupuncture, summarized in my latest article on the subject:

Most acupuncture treatment is still based on unscientific religious and philosophical principles. Despite extensive research over many decades, plausible scientific explanations for how traditional acupuncture might work have not been clearly validated. Clinical studies in humans have failed to find clear evidence of meaningful benefits for most conditions compared with sham interventions. 

There is little high-quality clinical research on veterinary acupuncture, and the widespread belief that it is an effective therapy is based mostly on anecdote and low-quality evidence. Better research evidence has been challenging to generate due both to the difficulty in creating an effective placebo comparator for acupuncture and to the impact of entrenched bias and unscientific beliefs among acupuncturists evaluating the practice.

Put more succinctly, the principles are either unscientific or unproven, it probably has little if any benefit, and it is relatively low-risk if applied sensibly and note used in place of science-based medicine. A recent clinical study in dogs with arthritis serves as additional support for these views.

Baker-Meuten A, Wendland T, Shamir SK, Hess AM, Duerr FM. Evaluation of acupuncture for the treatment of pain associated with naturally-occurring osteoarthritis in dogs: a prospective, randomized, placebo-controlled, blinded clinical trial. BMC Vet Res. 2020;16. doi:10.1186/S12917-020-02567-1

This was a nicely done study illustrating the use of some methods for objectively evaluating acupuncture in veterinary patients. Like most veterinary studies, it was small, with only 36 dogs (4 of which did not complete the study). The design was a crossover study, meaning all patients got both acupuncture and placebo treatment and were randomly assigned to get one or the other first with a washout period between treatments. This is a good way to minimize the errors that can be creep into the data if dogs with different characteristics get different treatments. For example, if the dogs in the placebo group had much worse arthritis than the dogs in the acupuncture group, it could easily look like the treatment was working even when it wasn’t.

There was also an effort at blinding, meaning the owners weren’t supposed to know when their dogs got placebo treatment and when they got acupuncture. This would help reduce the tendency of people who already believe in the effectiveness of acupuncture to see improvement due to caregiver placebo effects. Unfortunately, this blinding didn’t appear entirely successful. About 58% of owners correctly guessed when their dogs were getting acupuncture or placebo and only 19% guessed incorrectly (the rest said they couldn’t tell). While assessing the success of blinding is a good idea, a well-blinded study should have roughly equal numbers of people guessing real and placebo treatment. The veterinary staff and investigators were not blinded, which is unfortunate since this can not only bias the assessment of whether the treatment works but also subtly influence the perceptions of the owners, which may have been the case in this study.

The investigators used both subjective measures of effect, by both owners and veterinarians, and also objective measures, activity monitors and a force plate that measures the amount of weight a dog with arthritis can put on a painful limb. 

The treatment was a standardized acupuncture protocol based on a survey of veterinary acupuncturists, both from the Traditional Chinese Medicine school and also from the somewhat more scientific Medical Acupuncture trainingbackground. Some will still undoubtedly complain that this invalidates the results since theoretically acupuncturists treat every patient with a unique approach based on whatever set of theories they believe in and their own clinical experience. However, there was tremendous overlap among the vets surveyed in the approaches they used, and there is no evidence to support the claim that haphazard individualization of treatment works any better than standardized protocols. 

The treatment also involved electrical stimulation through the acupuncture needles. There is some debate about whether this is really “acupuncture” or simply a form of electrical nerve stimulation dressed up in folk medicine clothes. There is slightly better evidence for potential benefits to such electroacupuncture than for needling alone (“dry needling” as it is typically called) though the evidence is still not very robust.

The placebo was not a sham acupuncture treatment, as is often used. Instead, dogs were simply taken into the room where acupuncture would normally be done and spent an equivalent amount of time interacting with one of the veterinary staff. There are pros and cons to this approach. Defining sham acupuncture is tough because it is not clear that specific acupuncture points even exist or that it matters where you insert needles. In human studies, needling at a “fake” acupuncture point often has the same effect as needling at a “real.” This probably means the responses are mostly due to placebo effects and non-specific irritation from the needle insertion rather than some magical manipulation of energy or some special quality to the points traditionally used. However, if sham needling has the same effects as real acupuncture, then it doesn’t make a very good placebo control.

A non-treatment placebo avoids this problem, and it still controls for one of the most likely causes of placebo effects in animals, which is human contact. However, insofar as needling and electrical stimulation due have biological effects (whether clinically relevant or not), this is very different from just sitting in a room with a person, so arguably the placebo control isn’t very much like the treatment, and this opens the door for error.

In any case, the study did not show any convincing evidence of any benefit from acupuncture for dogs with arthritis. Both objective measures (activity monitor and force plate) showed no difference between placebo and acupuncture, as well as no difference between the baseline period and either the placebo or the acupuncture periods. This is a pretty solid negative finding. 

The subjective assessment by the veterinarians also showed no difference between acupuncture and placebo.

Of the subjective measures by the owners, the results were mixed. The overall questionnaire asking owners about effectiveness of treatment at the end of the study showed no difference between placebo and acupuncture. Another subjective measure employed by the owners showed no difference between placebo and acupuncture but did show a difference between the baseline period and the acupuncture period. Finally, yet another subjective assessment did show some difference between both baseline and placebo and the acupuncture treatment.

Inevitably, when multiple measures are used together, some will show a difference and others won’t. Showing a convincing effect requires a consistent pattern of positive results, especially from the more objective measures. Neither of those criteria were met, and the authors acknowledged that, “We rejected our hypothesis because we were unable to detect evidence of differences in the objective outcome measures…However, some treatment response was found using owner completed CMI to assess clinical function and chronic pain. These results should be cautiously interpreted while considering the natural fluctuations in the disease process of OA as well as the caregiver placebo effect.”

Of course, the authors practice acupuncture and clearly believe it is effective, so this is a difficult conclusion to reach. I admire their integrity in acknowledging that the study results did not match h their expectations, though I suspect it is unlikely to shake their confidence in their acupuncture practices. As is often the case in research reports, the authors make some attempt to find explanations for the failure to show an effect other than the most obvious, that the treatment doesn’t work. These include acknowledging that the purported benefits from acupuncture seen in studies of people with arthritis are quite small, considerably less than those from conventional treatments such as nonsteroidal anti-inflammatory drugs, which might mean that any effect from acupuncture might have been swamped in this study by the other treatments the dogs received. This, of course, raises the question of how worthwhile acupuncture is if its effects are so small as to be difficult to see in dogs getting treatments with better supporting evidence of benefit.

The authors also acknowledged that the apparent improvement seen in some dogs from placebo treatment likely represented a caregiver placebo effect. Such effects can, of course, also make therapies like acupuncture look like they work when they don’t in real clinical practice.

Bottom Line
This study found no benefit from acupuncture treatment for dogs with arthritis over placebo (essentially no treatment). Though the methods were not perfect, overall the study was designed, conducted, and analyzed appropriately, and it represents pretty strong evidence against the value  of acupuncture for treating arthritis pain in dogs. Given the lack of strong, compelling evidence in humans despite hundreds of studies over many decades, and the lack of good evidence in other veterinary studies, the most reasonable conclusion at this point is that acupuncture probably has little to no clinical benefit for arthritic dogs. If it is used at all, it should be as an adjunct, not a primary, treatment and only with full disclosure to owners about the likelihood that it is nothing more than a placebo.

Posted in Acupuncture | 1 Comment

A Discussion of Evidence-based Arthritis Management for Dogs

I had the enjoyable experience of participating in a Facebook Live Discussion with Dr. Hannah Capon of the Canine Arthritis Management Project about evidence-based arthritis management for dogs. We talked about how to evaluate treatments for arthritis and whether or not they are working, as well as taking questions about specific treatments from viewers.

Check it out!

Posted in Presentations, Lectures, Publications & Interviews | 5 Comments

Food is Love- Veterinarians and Nutrition

Food is Love
As a child, I was a big fan of the Peanuts cartoons. One of my favorite characters was Snoopy, a suave, bipedal beagle who wrote novels and engaged in breathtaking aerial combat with his nemesis, the Red Baron. Though Snoopy was unlike most other beagles I have known, he had one characteristic common to others of his breed, and indeed most dogs. When suppertime arrived, all other activities were forgotten, and he often launched into an exuberant, joyful suppertime dance. Every feeding was a celebration for Snoopy, a celebration not only of food but of the bond between dog and owner.

Few subjects generate the same intensity of emotion in pet owners as the question of what to feed our animal companions. Feeding our pets is the quintessential act of caring and love. And based on how most dogs and cats act at feeding time, it certainly seems like a highlight of the relationship for them! 

There is also a deep sense in most pet owners that choosing a pet food has tremendous significance for the health and well-being of their pets. Everyone wants to give their pets the “best” food, the food that will keep them active and happy and prevent illness for as long as possible. We have all been told most of our lives that what we eat affects our health, so we want to make good, healthy nutritional choices for our pets as well.

The food we give our pets food is also something we have control over. We naturally want to do everything we can to ensure our pets stay healthy, but many factors that influence the risk of disease are beyond our control. Food, at least, is something tangible that we know has an influence on health, and we can make choices about what we feed our pets that give us a sense of actively influencing their health. 

The significance and emotion attached to feeding can be good in that it motivates pet owners to seek information and try to make thoughtful, informed choices about what to feed. However, the pressure to find the “right” food can also make clients vulnerable to irrational decisions, and to exaggerated or unproven claims about nutrition and health. Like most medical subjects, nutrition is complicated and full of uncertainty and nuance, and the desire to find the perfect food to guarantee our pets good health is all too easy to exploit by those selling pet food or promoting particular feeding ideologies. Even smart, rational people can get swept away by enthusiasm or diet fads that may not be based on reliable scientific principles or evidence.

The role of veterinarians in decisions about nutrition is critical. We should be a reliable and convenient resource for owners, supporting rational feeding choices. But are we? Do pet owners rely on their vets for guidance about nutrition, and do we live up to our responsibility to provide it?

Do Clients Trust Us?
Unfortunately, the idea that veterinarians are not reliable sources of nutrition information is widespread. Many voices, from the media and breeders and even some of our colleagues within the profession, are loudly proclaiming that vets know little or nothing about pet nutrition, that what we do know is mere pet food industry propaganda, and that we are more concerned with selling food than with using nutrition to support the health of our patients [see examples below]. 

In general, the public sees vets as pretty trustworthy and likeable, sometimes even more so that other healthcare professionals.1 While there is some variability among studies in the extent to which pet owners trust our advice about nutrition, most show that a majority of clients desire advice from their vet on what to feed and have high confidence in this advice.2–7  However, the full picture is more complicated. The extent to which clients use and trust veterinary advice on nutrition varies with characteristics of owners, the pets they own, and the type of diets they choose to feed.

Not surprisingly, for example, owners feeding non-traditional diets rather than commercial pet food express less confidence in veterinary nutrition advice.4,7,8 One study found that owners feeding raw animal products to their pets were much less confident in veterinary nutrition advice than those not feeding any raw foods.4 About 54% of clients who did not feed raw trusted this advice “very much” while only 13% of raw feeders had this level of confidence. 

This seemed to generalize beyond nutrition to medical advice in general. In one study, advice about topics other than nutrition was considered highly trustworthy by 64% of clients who did not feed raw products, but only 36% of those clients who did.4 Raw feeders are less likely to trust veterinary recommendations about vaccination, flea control and other preventative health interventions.4,9 This suggests that pet owners who feed unconventional diets may have a broader distrust of conventional veterinary medicine and a more favorable view of alternative medicine. 

Such a connection between unconventional nutritional practices and a general distrust of science-based veterinary medicine seems likely given the consistent criticism of vaccines, pharmaceuticals, and other science-based interventions by veterinarians advocating for raw or other unconventional diets.10–12

Even those suspicious of veterinary medicine in general and committed to feeding their pets unconventional diets, however, still have some interest in veterinary nutrition advice. In one survey, 50% of raw feeders trusted veterinary advice in general “somewhat,” and 32% had this level of confidence in the nutrition knowledge of their vet.4 Surprisingly, among cat owners, a majority reported choosing to feed raw was influenced by advice from their veterinarian (58%) or from other veterinary sources (78%).4 This suggests that the problem may not necessarily be a true lack of trust in veterinarians as a source of advice about nutrition so much as a desire to follow veterinary advice so long as it is consistent with other values or beliefs related to pet health. Owners who feed raw or other unconventional diets, for example, often hold beliefs about the health benefits of such diets that have not been scientifically validated and which are unlikely to be affirmed by most veterinarians. However, these beliefs may be supported by vets with alternative philosophies or approaches, and raw feeders are likely to trust such vets more because their views are aligned.4,7–9,13

Another factor influencing both client feeding choices and their degree of trust in veterinarians as a source of information about nutrition is attitudes towards pet food producers. Pet owners, particularly those feeding unconventional diets, often express significant distrust in the motives and claims of commercial diet manufacturers and in the health value of commercial foods.2,4,8,9

Commercial pet diets are sometimes seen as “junk food,” equivalent in nutritional and health value to human convenience and snack foods because both are “processed.” Pet owners sometimes express concerns about the health effects of grains, organic versus conventional ingredients, genetically-modified ingredients, meat from animals that are ill or have died or been euthanized, and other real or imagined components of commercial diets. There have also been some very serious incidents of real harm to pets from adulterated or contaminated commercial diets, and many pet owners are aware of these.14 Such concerns undermine confidence not only in pet food manufacturers but in veterinarians because we are seen recommending primarily commercial diets and as having potential financial and other conflicts of interest that influence these recommendations.

Should Clients Trust Us?
The arguments against heeding veterinary advice about nutrition are ultimately bad arguments which lead clients to make decisions based on misinformation, fear, marketing propaganda, and other unreliable foundations. Like many bad arguments, however, there is some core of truth to each of them that we have to address in order to protect our clients from being misled. 

What Do Vets Know about Nutrition?
The idea that veterinarians (or at least those practicing conventional science-based medicine) know nothing about nutrition is false. All veterinarians learn about the importance of nutrition and about the effect of food and feeding practices on health in veterinary school. Some of this education is in dedicated nutrition courses, but most of it is incorporated into our education about specific species and health conditions and into our hands-on clinical training. 

However, there is no denying that the quantity and quality of the nutrition education most vets receive is insufficient. Many veterinary schools do not have full-time board-certified veterinary nutritionists on faculty teaching courses in nutrition.15 Surveys of veterinarians consistently find that while we understand the importance of nutrition in health, we rarely feel confident in our training or ability to provide nutritional counseling.15–19 Apart from the small number of board-certified nutritionists, most small-animal veterinarians cannot fairly claim to be experts in pet nutrition. 

So are the critics right? I would argue they are not. While most veterinarians would like more and better training about nutrition than they have, we are still well equipped to offer pragmatic, science-based advice. We have both the general knowledge of physiology and nutrition and the ability to critically evaluate new research and incorporate it into our recommendations. This equips us to offer sound advice about nutrition to our clients.

Crucially, the alternative sources that clients turn to when they don’t trust their veterinarian’s nutrition knowledge are unquestionably less informed and less reliable. Companies marketing unconventional diets, breeders and other lay persons with little or no scientific training, and the information jungle that is the Internet cannot provide the quality or reliability of advice about nutrition that we can as veterinarians. 

Proponents of unconventional feeding practices, including many veterinarians committed to alternative medical approaches, will tell clients and conventional veterinarians that they are nutrition experts because they have “educated” themselves, above and beyond the information most veterinarians receive in school. This “education,” however, is nothing more than seeking and accepting ideas and claims that lack scientific validation but conform to the ideological biases these advocates bring to their search. 

The claim that dogs should eat a “species appropriate” diet extrapolated from what wolves or other wild canids might eat is a common example of this kind of ideologically motivated false expertise. Dogs are not wolves, and they have significant anatomic and functional differences between wolves and domestic dog. Many of these involve their systems for eating and digesting food. For all the millennia dogs have lived with humans, they have scavenged our leftovers and shared our food, and evolution has adapted them to a much more varied and less meat-centered diet than wolves or many other wild canids.20–25

Similarly, unsupported claims about the dangers of grains and carbohydrates,26–31 the benefits of raw32–35 and organic36–40 ingredients, the risks of genetically modified ingredients41–44 and various preservatives or other food additives45, and many other such ideas are frequently identified as examples of advanced knowledge or understanding that most vets lack. However, these do not constitute reliable or scientifically informed advice. Most of these claims are unsupported by good evidence, and many are clearly wrong. Even with the inadequacies in our nutrition training, we are a more reliable source of information and advice for pet owners about nutrition than the alternatives they may turn to if they lose trust in us.

Is all Our Knowledge Just Industry Propaganda
Once again, there is some legitimacy to the claim that the pet food industry has a biased perspective on pet nutrition, and that this industry has entirely too much influence on veterinary education and the veterinary profession. The giving of gifts from industry representatives has been clearly linked to prescribing behavior in physicians,46,47 and it is unlikely that veterinarians are immune to this effect. The common practice of showering students and practitioners with gifts, from coffee mugs to free food to vacations nominally intended as “continuing education,” is a real threat to both the true objectivity of veterinarians and the trust of our clients. Such practices should absolutely be discouraged.

Similarly, there is good evidence that industry funding influences the outcomes of clinical research in ways that is often in favor of the funder’s products.48,49 The concern that the scientific foundations for our recommendations about nutrition may reflect the biases of industry are not unfounded. Fortunately, the impact of such sponsorship bias on research can be mitigated with appropriate methods for controlling bias50, from trial registration and a priori publication of research protocols to strict policies banning any involvement by the funder in the design, conduct, and analysis of research studies. Ideally, more independent funding from academic institutions, non-profit organizations, and government entities would also help to reduce the influence of industry on research, though such funders have, of course, their own biases.

Once again, however, we must understand that these legitimate concerns about potential bias in the information veterinarians receive and provide concerning pet nutrition does not validate the dismissal of veterinary advice nor the acceptance of alternative information sources. We cannot simply declare all nutrition research worthless due to industry bias and make up whatever alternative theories or facts suit us. All data in science comes with limitations, and all conclusions are provisional and must be altered over time as the quality of our data improves. Such evidence is still, however, far superior to the unsubstantiated theories, intuition, and uncontrolled personal experience usually cited in support of alternative nutritional practices. 

It is also often overlooked that all scientific research incorporates biases of others kinds as well, beyond simply that of funding source, and that this influences research results as much or more than the funding source.51 Studies funded by companies producing unconventional diets or conducted by dedicated evangelists for such diets, are no less susceptible to bias than those funded by conventional pet food companies. 

Concerns raised in 2018 about potential negative health effects of grain-free and other unconventional diets52–54, for example, were recently strongly challenged in a narrative literature review.55 This review generated some controversy when the authors turned out to have financial ties to a prominent manufacturer of grain-free dog food. Conflict of interest and bias are ubiquitous and not limited to research supporting conventional or commercial diets. We must evaluate all claims and all evidence critically and be mindful of potential bias while not giving up on evidence-based medicine, which has proved its superiority to anecdote and opinion beyond question.

Veterinarians’ understanding of nutrition science and the physiology of our patients is sound The evidence for many specific nutritional interventions is quite strong;56 certainly stronger than that for the sort of claims offered by those who claim our knowledge is biased and worthless. Tens of thousands of dogs and cats thrive on conventional diets for many years, and while we will likely discover ways to significantly improve how and what we feed through future research, the notion that these diets are grossly inappropriate or harmful is nonsense. Until the alternatives to these diets can generate evidence at least as good as that for current practices, it is disingenuous to dismiss veterinary nutrition counseling on the basis of perceived industry bias.

Do Vets Care More About Selling Food than Patient Health?
I suspect no one will be surprised that my answer to this question is an emphatic “No!” Veterinarians do make money selling pet food, especially therapeutic diets intended for management of medical conditions such as chronic kidney disease, urinary tract stones, food allergies, and others. This is changing as online sales grow, and far more pet food is purchased from sources other than veterinary clinics and hospitals.57 However, food is a revenue stream just as are all the other medications, procedures, and services we provide for our patients. 

While financial incentives can influence the behavior of veterinarians and other healthcare providers, the idea that this is central motivation or that we would sacrifice patient health for profit is nonsense. Veterinarians are individuals committed to animal welfare, and there is no question we could make far more money in much easier jobs if that were our primary concern. Given the training, hard work, stress, and debt we take on to be part of this profession, none of us are the sort of people who would sacrifice our patients or our ethics for the revenue we get from selling pet food. Very few of my clients buy their food from my hospital, and I routinely direct owners to reliable sources for fresh commercial and balanced homemade diets formulated by veterinary nutritionists. 

Unfortunately, the folks who are likely to believe vets are greedy and unconcerned about their patients’ welfare aren’t likely to be swayed by any argument or evidence. I will, however, point out that once again the alternatives to conventional diets also nearly all make money for someone, whether they are manufactured alternative diets, books written by veterinarians to promote such diets, or consultation fees these vets charge for the time they spend teaching clients about their views on nutrition. No one taking any position on what constitutes healthy nutrition for dogs and cats is doing so without some sort of bias, and potential financial bias is as likely on either side of the debate.

How Can We Best Help Our Clients?
The bottom line is that veterinarians have useful, reliable information to offer clients about nutritional choices for their pets. There is good scientific evidence to support many of our recommendations, from low-calcium and reduced calorie diets for large-breed puppies58–64 to specially formulated renal diets for elderly cats with chronic kidney disease65. As general practitioners, our fundamental understanding of physiology and nutrition is sound and useful even though we are not nutrition specialists, just as our understanding of heart disease and diabetes is sound and useful even though we are not boarded cardiologists or internists. We must recognize our own strengths and use what we know to support our clients in making well-informed choices.

One of the most useful insights we can offer many clients is that there is no “perfect” diet that will guarantee only good health for their pets, and there are few diets that are egregiously “toxic” and certain to lead to illness. Health is a complex and multifactorial state, and while nutrition is unquestionably important, simplistic notions or good and bad foods or ingredients and excessive anxiety about finding the “right” foods do more harm than good. An unhealthy obsession with selecting very specific or extreme diets for perceived health values is now widely recognized as an eating disorder in humans, usually referred to as “orthorexia.”66 Pet owners may be subject to a similar unrealistic obsession with nutrition as a means of warding off disease in their pets.

Helping pet owners to make good choices about nutrition includes helping reduce the pressure they feel that every choice is critical and will make or break their pets’ health. This is an understanding we have as healthcare professionals and which we can share with our clients.

We must also, as always, strive to do better in the area of nutrition as in all aspects of our work. Practitioners should see pursuing continuing education in nutrition from reputable sources as a necessary part of our professional development. Veterinary schools should make nutrition a stronger element of the curriculum. And we should recognize the limits of our expertise and be prepared to refer clients when they need nutritional guidance we cannot provide. Board-certified nutritionists in academic and private practice can be excellent resources in developing optimal nutritional plans for individual patients and in countering the ubiquitous myths and misinformation our clients may be exposed to. 

Finally, we should acknowledge the legitimate elements in the criticism of our knowledge and practices. While the pet food industry produces many healthful products and generates much useful resources, profit motives do influence the evidence and the education associated with industry. Clinicians need to be less eager to accept gifts and favors from representatives of industry, and we need to incorporate a recognition of potential funding bias in our critical evaluation of research evidence in the area of nutrition. The best answer to our critics and those promoting unsubstantiated and unscientific alternative approaches to evidence-based nutrition advise is not to cede the field but to work harder to meet our responsibilities to our clients and our patients.

1.          Royal College of Veterinary Surgeons. Vets amongst the most trusted professionals, according to survey – Professionals. RCVS News. https://www.rcvs.org.uk/news-and-views/news/vets-amongst-the-most-trusted-professionals-according-to-rcvs/. Published 2019. Accessed September 4, 2020.

2.        Michel KE, Willoughby KN, Abood SK, et al. Attitudes of pet owners toward pet foods and feeding management of cats and dogs. J Am Vet Med Assoc. 2008;233(11):1699-1703. doi:10.2460/javma.233.11.1699

3.        Evason M, Peace M, Munguia G, Stull J. Clients’ knowledge, attitudes, and practices related to pet nutrition and exercise at a teaching hospital. Can Vet J. 2020;61(5):512-516. https://www.cabi.org/vetmedresource/abstract/20203199863. Accessed August 23, 2020.

4.        Morgan SK, Willis S, Shepherd ML. Survey of owner motivations and veterinary input of owners feeding diets containing raw animal products. PeerJ. 2017;5:e3031. doi:10.7717/peerj.3031

5.        Kamleh M. Perceptions and attitudes towards human and companion animal nutrition, nutrition education and nutrition guidance received from healthcare professionals. 2019. https://atrium.lib.uoguelph.ca/xmlui/bitstream/handle/10214/17482/Kamleh_May_201909_PhD.pdf?sequence=3&isAllowed=y. Accessed September 7, 2020.

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7.        Connolly KM, Heinze CR, Freeman LM. Feeding practices of dog breeders in the United States and Canada. J Am Vet Med Assoc. 2014;245(6):669-676. doi:10.2460/javma.245.6.669

8.        Morelli G, Bastianello S, Catellani P, Ricci R. Raw meat-based diets for dogs: survey of owners’ motivations, attitudes and practices. BMC Vet Res. 2019;15(1):74. doi:10.1186/s12917-019-1824-x

9.        Lenz J, Joffe D, Kauffman M, Zhang Y, LeJeune J. Perceptions, practices, and consequences associated with foodborne pathogens and the feeding of raw meat to dogs. Can Vet J. 2009;50(6):637. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2684052/. Accessed August 24, 2020.

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13.      Dodd SAS, Cave NJ, Adolphe JL, Shoveller AK, Verbrugghe A. Plant-based (vegan) diets for pets: A survey of pet owner attitudes and feeding practices. Suchodolski JS, ed. PLoS One. 2019;14(1):e0210806. doi:10.1371/journal.pone.0210806

14.      Bischoff K, Rumbeiha WK. Pet Food Recalls and Pet Food Contaminants in Small Animals: An Update. Vet Clin North Am Small Anim Pract. 2018;48(6):917-931. doi:10.1016/j.cvsm.2018.07.005

15.      Becvarova I, Prochazka D, Chandler ML, Meyer H. Nutrition Education in European Veterinary Schools: Are European Veterinary Graduates Competent in Nutrition? J Vet Med Educ. 2016;43(4):349-358. doi:10.3138/jvme.0715-122R1

16.      Bruckner I, Handl S. Survey on the role of nutrition in first?opinion practices in Austria and Germany: An evaluation of knowledge, preferences and need for further education. J Anim Physiol Anim Nutr (Berl). June 2020:jpn.13337. doi:10.1111/jpn.13337

17.      Kamleh MK, Khosa DK, Dewey CE, Verbrugghe A, Stone EA. Ontario Veterinary College First-Year Veterinary Students’ Perceptions of Companion Animal Nutrition and Their Own Nutrition: Implications for a Veterinary Nutrition Curriculum. J Vet Med Educ. May 2020:e0918113r1. doi:10.3138/jvme.0918-113r1

18.      Lumbis RH, Scally M. Knowledge, attitudes and application of nutrition assessments by the veterinary health care team in small animal practice. J Small Anim Pract. 2020;61(8):494-503. doi:10.1111/jsap.13182

19.      Abood SK. Teaching and Assessing Nutrition Competence in a Changing Curricular Environment. J Vet Med Educ. 2008;35(2):281-287. doi:10.3138/jvme.35.2.281

20.      Serpell J. The Domestic Dog: Its Evolution, Behavior and Interactions with People. 2nd ed. (Serpell J, ed.). Cambridge University Press; 2017.

21.      Sturgeon A, Jardine CM, Weese JS. COMPARISON OF THE FECAL MICROBIOTA OF WILD WOLVES, DOGS FED COMMERCIAL DRY DIETS AND DOGS FED RAW MEAT DIETS. In: Proceedings 2014 ACVIM Research Forum. Vol 28. John Wiley & Sons, Ltd (10.1111); 2014:1346-1374. doi:10.1111/jvim.12375

22.      Axelsson E, Ratnakumar A, Arendt M-L, et al. The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature. 2013;495(7441):360-364. doi:10.1038/nature11837

23.      Ziesenis A, Wissdorf H. [The ligaments and menisci of the femorotibial joint of the wolf (Canis lupus L., 1758)–anatomic and functional analysis in comparison with the domestic dog (Canis lupus f. familiaris)]. Gegenbaurs Morphol Jahrb. 1990;136(6):759-773. http://www.ncbi.nlm.nih.gov/pubmed/2099308. Accessed December 28, 2018.

24.      Wayne RK. Molecular evolution of the dog family. Trends Genet. 1993;9(6):218-224. http://www.ncbi.nlm.nih.gov/pubmed/8337763. Accessed December 28, 2018.

25.      Reiter T, Jagoda E, Capellini TD. Dietary Variation and Evolution of Gene Copy Number among Dog Breeds. 2016. doi:10.1371/journal.pone.0148899

26.      Laflamme D, Izquierdo O, Eirmann L, Binder S. Myths and Misperceptions About Ingredients Used in Commercial Pet Foods. Vet Clin North Am Small Anim Pract. 2014;44(4):689-698. doi:10.1016/j.cvsm.2014.03.002

27.      Murray SM, Fahey GC, Merchen NR, Sunvold GD, Reinhart GA. Evaluation of selected high-starch flours as ingredients in canine diets. J Anim Sci. 1999;77(8):2180-2186. http://www.ncbi.nlm.nih.gov/pubmed/10461997. Accessed December 18, 2018.

28.      de-Oliveira LD, Carciofi AC, Oliveira MCC, et al. Effects of six carbohydrate sources on diet digestibility and postprandial glucose and insulin responses in cats1. J Anim Sci. 2008;86(9):2237-2246. doi:10.2527/jas.2007-0354

29.      Bazolli RS, Vasconcellos RS, de-Oliveira LD, Sá FC, Pereira GT, Carciofi AC. Effect of the particle size of maize, rice, and sorghum in extruded diets for dogs on starch gelatinization, digestibility, and the fecal concentration of fermentation products1. J Anim Sci. 2015;93(6):2956-2966. doi:10.2527/jas.2014-8409

30.      Carciofi AC, Takakura FS, de-Oliveira LD, et al. Effects of six carbohydrate sources on dog diet digestibility and post-prandial glucose and insulin response. J Anim Physiol Anim Nutr (Berl). 2008;92(3):326-336. doi:10.1111/j.1439-0396.2007.00794.x

31.      Laflamme D. Cats and carbohydrates: Why is this still controversial? In: 2018 ACVIM Forum. Seattle, WA; 2018.

32.      McKenzie B. Debating Raw Diets. Vet Pract News. January 2019:30-31. https://www.veterinarypracticenews.com/debating-raw-diets-january-2019/.

33.      Freeman LM, Chandler ML, Hamper BA, Weeth LP. Current knowledge about the risks and benefits of raw meat-based diets for dogs and cats. J Am Vet Med Assoc. 2013;243(11):1549-1558. doi:10.2460/javma.243.11.1549

34.      Schlesinger DP, Joffe DJ. Raw food diets in companion animals: a critical review. Can Vet J = La Rev Vet Can. 2011;52(1):50-54. http://www.ncbi.nlm.nih.gov/pubmed/21461207. Accessed October 27, 2018.

35.      Gyles C. Raw food diets for pets. Can Vet J = La Rev Vet Can. 2017;58(6):537-539. http://www.ncbi.nlm.nih.gov/pubmed/28588324. Accessed December 28, 2018.

36.      Bara?ski M, ?rednicka-Tober D, Volakakis N, et al. Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. Br J Nutr. 2014;112(05):794-811. doi:10.1017/S0007114514001366

37.      ?rednicka-Tober D, Bara?ski M, Seal CJ, et al. Higher PUFA and n-3 PUFA, conjugated linoleic acid, ?-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses. Br J Nutr. 2016;115(06):1043-1060. doi:10.1017/S0007114516000349

38.      Dangour AD, Dodhia SK, Hayter A, Allen E, Lock K, Uauy R. Nutritional quality of organic foods: a systematic review. Am J Clin Nutr. 2009;90(3):680-685. doi:10.3945/ajcn.2009.28041

39.      Mie A, Andersen HR, Gunnarsson S, et al. Human health implications of organic food and organic agriculture: a comprehensive review. Environ Health. 2017;16(1):111. doi:10.1186/s12940-017-0315-4

40.      Smith-Spangler C, Brandeau ML, Hunter GE, et al. Are Organic Foods Safer or Healthier Than Conventional Alternatives? Ann Intern Med. 2012;157(5):348. doi:10.7326/0003-4819-157-5-201209040-00007

41.      Landrum AR, Hallman WK, Jamieson KH. Examining the Impact of Expert Voices: Communicating the Scientific Consensus on Genetically-modified Organisms. Environ Commun. August 2018:1-20. doi:10.1080/17524032.2018.1502201

42.      National Academies of Sciences E and M. Genetically Engineered Crops. Washington, D.C.: National Academies Press; 2016. doi:10.17226/23395

43.      Van Eenennaam AL, Young AE. Prevalence and impacts of genetically engineered feedstuffs on livestock populations1. J Anim Sci. 2014;92(10):4255-4278. doi:10.2527/jas.2014-8124

44.      Nicolia A, Manzo A, Veronesi F, Rosellini D. An overview of the last 10 years of genetically engineered crop safety research. Crit Rev Biotechnol. 2014;34(1):77-88. doi:10.3109/07388551.2013.823595

45.      McKenzie B. Is banning “artificial” ingredients based on fear or science? Vet Pract News. March 2019:36-37.

46.      King M, Bearman PS. Gifts and influence: Conflict of interest policies and prescribing of psychotropic medications in the United States. Soc Sci Med. 2017;172:153-162. doi:10.1016/j.socscimed.2016.11.010

47.      Grande D, Frosch DL, Perkins AW, Kahn BE. Effect of Exposure to Small Pharmaceutical Promotional Items on Treatment Preferences. Arch Intern Med. 2009;169(9):887. doi:10.1001/archinternmed.2009.64

48.      Fabbri A, Lai A, Grundy Q, Bero LA. The Influence of Industry Sponsorship on the Research Agenda: A Scoping Review. Am J Public Health. 2018;108(11):e9-e16. doi:10.2105/AJPH.2018.304677

49.      Lundh A, Lexchin J, Mintzes B, Schroll JB, Bero L. Industry sponsorship and research outcome. Cochrane database Syst Rev. 2017;2:MR000033. doi:10.1002/14651858.MR000033.pub3

50.      Ioannidis JPA. How to make more published research true. PLoS Med. 2014;11(10):e1001747. doi:10.1371/journal.pmed.1001747

51.      Ioannidis JPA. Why Most Published Research Findings Are False. PLoS Med. 2005;2(8):e124. doi:10.1371/journal.pmed.0020124

52.      Freeman LM, Stern JA, Fries R, Adin DB, Rush JE. Diet-associated dilated cardiomyopathy in dogs: what do we know? J Am Vet Med Assoc. 2018;253(11):1390-1394. doi:10.2460/javma.253.11.1390

53.      Kaplan JL, Stern JA, Fascetti AJ, et al. Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. Loor JJ, ed. PLoS One. 2018;13(12):e0209112. doi:10.1371/journal.pone.0209112

54.      Adin D, DeFrancesco TC, Keene B, et al. Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type. J Vet Cardiol. 2019;21:1-9. doi:10.1016/J.JVC.2018.11.002

55.      McCauley SR, Clark SD, Quest BW, Streeter RM, Oxford EM. Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. J Anim Sci. 2020;98(6). doi:10.1093/jas/skaa155

56.      Davies M. Veterinary clinical nutrition: success stories: an overview. Proc Nutr Soc. 2016;75(03):392-397. doi:10.1017/S002966511600029X

57.      An Uptick in Clicks and Bricks for Pet Food: An Omnichannel Perspective – Nielsen. Nielsen.com. https://www.nielsen.com/us/en/insights/article/2018/an-uptick-in-clicks-and-bricks-for-pet-food-an-omnichannel-perspective/. Published 2018. Accessed September 7, 2020.

58.      Schoenmakers I, Hazewinkel HA, Voorhout G, Carlson CS, Richardson D. Effects of diets with different calcium and phosphorus contents on the skeletal development and blood chemistry of growing great danes. Vet Rec. 2000;147(23):652-660. doi:10.1136/VR.147.23.652

59.      Dobenecker B. Influence of Calcium and Phosphorus Intake on the Apparent Digestibility of These Minerals in Growing Dogs. J Nutr. 2002;132(6):1665S-1667S. doi:10.1093/jn/132.6.1665S

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61.      Kasström H. Nutrition, Weight Gain and Development of Hip Dysplasia. Acta Radiol Diagnosis. 1975;16(344_suppl):135-179. doi:10.1177/0284185175016S34412

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63.      Kealy RD, Lawler DF, Ballam JM, et al. Five-year longitudinal study on limited food consumption and development of osteoarthritis in coxofemoral joints of dogs. J Am Vet Med Assoc. 1997;210(2):222-225. http://www.ncbi.nlm.nih.gov/pubmed/9018356. Accessed September 11, 2020.

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Examples of Negative Propaganda about Vets and Nutrition
Don’t listen to what your vet has to say about feeding your dog: vets know virtually nothing about animal nutrition… Most veterinarians have ZERO training in nutrition.

My education came from the food company representatives; those that sponsored events while I was a student, and later the food reps that visited the veterinary practices I worked in.

The dog food industry is now dominated by large multinational consumer corporations who, in my opinion, are far more interested in profit than the health of your pet. The entire pet food industry is not on the whole very ethical. Not only do they produce some pretty unhealthy stuff, they also do some pretty unethical things.
Andrew Jones, DVM
Pets Naturally Magazine
March, 2016

Because nutrition isn’t viewed as an integral part of disease management, many vet students graduate not recognizing the monumental role nutrition plays in overall health. They don’t have enough knowledge to institute innovative nutritional protocols to manage degenerative disease in their patients.

Worse still is that at many of the veterinary schools in North America, the instruction vet students DO receive comes from the biggest pet food producers in the business. Needless to say, the “training” the students receive from these companies is heavily slanted in favor of the products they sell, which are inevitably highly processed. Currently, none of the major pet food companies sell biologically appropriate diets, so these foods are portrayed as dangerous.

Unfortunately, the majority of board-certified veterinary nutritionists have also been schooled primarily about processed pet diets, and believe it or not, major pet food manufacturers frequently pay the tuition for DVMs studying to become veterinary nutritionists. So when a veterinary nutritionist recommends X, Y or Z food — or discourages feeding raw or homemade diets, which is common — keep in mind that many practicing veterinary nutritionists are obligated in some way to a pet food manufacturer.

Karen Becker, DVM
Healthy Pets, Mercola.Com
July, 2017

The problem with your average veterinarian giving you nutritional advice is that they have had very little nutrition training… Most vets get their information from other biased or uninformed vets, they believe what they read in the vet publications sponsored by kibble companies, they get their info from sales representatives of the big kibble companies or from limited private reading. I am sure you understand why kibble companies do not make the best reference source as they are only interested in selling their products and are not open to alternative diets even if that might be actually needed.

Jennifer Carter
Volhard Dog Nutrition
January, 2020

How much do veterinarians learn about nutrition? The sad answer is not a lot, and often our information is biased…the doctors graduating from veterinary schools are biased at best. At worst, they are very “anti-natural” and rabid fans of these national brands…Most well-known pet food companies have been sold to mega conglomerates like Colgate-Palmolive, who often add plant and animal by-products and various chemical preservatives, additives, flavorings, and colorings to the products. 

Doctors must strike out on their own to seek a more balanced approach to diet and nutrition.  But they are not inclined to do this unless they are driven to expand beyond conventional medicine. Since most are satisfied with the status quo, it is hard to find a veterinarian who is not afraid to challenge his long-held beliefs and actually look at other dietary and nutritional options for his patients. 
Shawn Messonier, DVM
Animal Wellness Magazine

Hills, Purina, and Iams are ingrained into the consciousnesses of every veterinarian from their professional infancy to their grave. Processed food is in our blood – Yuck. How can you expect a veterinarian to be open to the idea that real, raw food is anything but dangerous for pets?

Veterinary students learn about dog and cat nutrition from a book written by a major pet food company. The nutritionist that teaches them has usually had their education underwritten by a major pet food company. Major pet food companies provide free food for vet students and also the teaching hospitals where they are learning about veterinary norms.

Who has money to fund research into pet nutrition? You guessed it, the major pet food companies. Most continuing education for veterinarians regarding nutrition is sponsored by pet food companies. 

My hope is that the grassroots, raw pet food movement will cause more vets to see the light as they encounter healthy animals being fed these diets. Perhaps the conventional nutrition programming can be unlearned and the eyes of veterinarians opened to the truth.

Doug Knueven, DVM
Blog Post
May, 2014

Posted in Nutrition | 14 Comments

From SkeptVet TV- “Natural” Remedies & Placebos in Pets

I’ve added a couple of short videos on the subjects of “natural” remedies and placebo effects in pets to my YouTube channel, SkeptVet TV.

Posted in SkeptVet TV | Leave a comment

The Latest on Dietary Risk Factors for Dilated Cardiomyopathy (DCM) & Misleading Media Spin by Grain-free Diet Manufacturers

Along with many in the veterinary profession, I have been following the concerns about diet-associated heart disease in dogs since 2018. A type of severe disease known as dilated cardiomyopathy (DCM) has been reported in dogs not previously thought prone to developing this malady, and it has been associated with the feeding of certain diets. These include grain-free diets, diets with exotic protein sources, and diets produced by small-scale or “boutique” manufacturers. Collectively, these foods have been referred to in some scientific papers as “BEG” diets.

Here are my previous posts on the subject-

Grain-free Diets and Heart Disease in Dogs– August, 2018

Evidence Update: Grain-free and other “BEG” Diets Associated with Heart Disease in Dogs– December, 2018

FDA Update on Grain-free Diets and Heart Disease in Dogs– January, 2019

I also recently wrote an article for Veterinary Practice News on the subject critically evaluating a narrative literature review that seemed to dismiss concerns about BEG diets and DCM. Unfortunately, this review had a number of limitations, including selective reporting of relevant findings and an undisclosed conflict of interest. Some of the authors are employees of a company which produces grain-free diets and which is actively campaigning against the idea that these diets could have negative health effects. BSM, the research group behind the review, has also accepted grant funding from a manufacturer of ingredients for grain-free diets for further research into the subject, which raises concerns about the risk of funding bias.

My most recent conclusion on the subject was this:

The scientific issue, meaning the potential causal relationship between various nutritional factors and DCM, is unresolved. Further research will be needed to confirm or refute hypotheses about any causal role of pulses, exotic protein sources, and boutique pet foods in this disease. As new research is published, however, reviewers and readers should take into account the role of financial considerations of the conclusions of various stakeholders, and the relevance of these impacts to the potential for bias in the conduct and analysis of the research.

About the same time my article was published, a virtual conference on the subject of DCM was held through Kansas State University in September, 2020

This conference included a statement from an official of the FDA Center for Veterinary Medicine (CVM), presentations by several pet food manufacturers and representatives of industry, reports from members of the BSM research group responsible for the review article I mentioned earlier, and other research presentations. Some of the abstracts and presentations are available on the conference web site while others are not. None of the presentations refer to published, peer-reviewed research. 

Not surprisingly, representatives of industry and BSM were highly critical of the hypothesis that diet might be associated with DCM in dogs, and they provided arguments and limited unpublished data to contradict this hypothesis. Other researchers provided similarly unpublished data showing that dogs with DCM who were fed BEG diets recovered from the disease with diet change and supplementation of the amino acid taurine, data which supports the hypothesized causal relationship between these diets and DCM. The FDA official was studiously neutral on the scientific question, trying to explain the role of the agency in monitoring pet food safety and keeping the public informed while not unnecessarily interfering with the interests of the pet food industry.

None of the information presented at the conference establishes a definitive answer to the role of diet in DCM, and the question requires further research to answer. However, several manufacturers have since made public statements egregiously misrepresenting the state of the science and the position of the FDA. Champion Pet Foods, for example, issued this deceptive press release:

FDA Provides Clarity About Canine Heart Disease and Diet- Evidence Finds No Causal Relationship to Grain-Free Food

BOULDER, COLORADO, November 5, 2020 – The U.S. Food and Drug Administration (FDA) issued an update this week that concluded there is no scientific evidence that a grain-free diet causes canine dilated cardiomyopathy (DCM). The agency outlined the multiple potential factors that can, alone or in combination, contribute to dogs developing this rare and scientifically complex disease. The agency concluded that there is nothing inherently unsafe about a grain-free diet. This is good news for pet lovers everywhere who, for years, have seen their dogs thrive on grain-free diets for healthy and wholesome nutrition.

This misrepresents the most recent statement from the FDA, which does not offer any such conclusion:

Historically, DCM has been primarily linked to genetic predisposition in certain breeds, but in the context of these atypical cases, emerging science appears to indicate that non-hereditary DCM is a complex medical condition that may be affected by the interplay of multiple factors such as genetics, underlying medical conditions, and diet.

FDA has not taken regulatory action against or declared any specific pet food products unsafe or definitively linked to DCM. As the scientific community looks further into the role that diet may play in these cases, we hope to explore additional avenues about ingredient levels, nutrient bioavailability, ingredient sourcing, and diet processing to determine if there are any common factors. We have asked pet food manufacturers to share diet formulation information, which could substantially benefit our understanding of the role of diet.

FDA sees this as an ongoing, collaborative, multidisciplinary scientific venture… to assess the available information and fill data gaps to determine what factors may contribute to the development of non-hereditary DCM.

Other industry organizations have issued similar statements implying that the FDA has concluded there is no causal relationship between DCM and diet, when in reality the agency has merely left the question open for further study. 

Science inherently involves controversy. It functions best as a process focused on challenging and striving to prove hypotheses wrong. By its very nature, the scientific method requires criticizing the research of other scientists in order to expose bias and error in hypotheses and research methods. Unfortunately, this necessary level of controversy is unnecessarily exacerbated by the influence of ego, reputation, career goals, and money on how individual defend or attack scientific hypotheses and data. The issue of diet and DCM illustrates both the inevitable and the unnecessary conflict involved in the assessment of new ideas by the scientific community.

The core question, whether certain diets or ingredients or methods of formulation have a causal role in DCM and how, precisely, this might work remains unanswered. Those researchers hypothesizing a causal relationship and investigating this idea have always been careful to point out that the data is not yet clear nor definitive. The FDA has also been clear that they are responsible for informing the public of and investigating potential risks, but the agency has made no firm conclusion on the role of diet in DCM. 

While it is understandable that critics of this hypothesis would try to undermine the arguments and evidence put forward by proponents, it is unfortunate when this is done in a disingenuous or outright misleading way. And though, undoubtedly, these critics have a genuine skepticism of the hypothesis based on the limited evidence available, the role of financial bias cannot be ignored. The publication of concerns that grain-free diets might lead to DCM, and the word-of-mouth among breed groups and pet owners with firsthand experience of this disease, have significantly affected sales of these diets. It would be naïve to imagine that manufacturers of BEG diets are unaffected in their opinions by this fact.

Posted in Nutrition | 1 Comment

Evidence Update: The Latest on Pheromones for Behavior Problems in Dogs and Cats

I have been following the research literature investigating the use of pheromones to manage behavior problems in dogs and cats since my first post of the subject in 2010. Here is a rough timeline of my conclusions over that period:

2010- Pheromone Therapy for Dogs and Cats: What’s the Evidence?
The limitations in the quality of the evidence mean we cannot definitively declare that pheromone therapy doesn’t work. What we can say is that based on the best evidence to date, it does not appear to have a benefit. Further study is certainly reasonable, but as always I question the wisdom and the ethics of widespread sale and use of products which, despite years of testing, don’t seem to have much evidence that they work.

2010- Does the Pheromone DAP Reduce Stress in Dogs Having Surgery?
“It is possible that purified or synthetic pheromones may ultimately have a role to play in treating behavioral problems in dogs and cats, or in otherwise ameliorating the stresses associated with illness and medical care. But the products currently on the market, and widely used, have so far not done a very impressive job of proving their value. Harmless? Probably. But also perfect candidate for placebo-by-proxy effects, making owners and veterinarians feel better rather than our patients.”

2016-Evidence Update: Pheromone Therapy for Stress in Cats
“The results were pretty clear. While the clinic environment is generally more stressful than the home (reflected in differences in heart rate and respiratory rate), cats tolerate being handled and restrained in an unfamiliar environment better than in their own home (reflected in behavioral differences). In neither environment did the pheromone make any difference in the cats’ responses compared with placebo. The authors concluded that the pheromone had no influence on the markers of stress evaluated in this study.

Given the consistency of results across a number of studies, it is pretty clear at this point that pheromone products are unlikely to have any beneficial effects for dogs and cats.”

2017- Evidence Update: Feline Facial Pheromone Doesn’t Reduce Stress or URIs in Shelter Cat Study
“The findings, however, were pretty consistently negative. No difference was seen in stress scores or in the occurrence of URI between cats exposed to the pheromone and those exposed to the placebo. No evidence of harm from the pheromone treatment was seen, though this was not specifically sought.

As usual, no single study should be taken as the definitive answer to any medical question. However, in light of the fact that pheromones have been in use and studied extensively for decades and strong, consistent evidence of significant benefits has not been seen, this study strengthens the argument that these products do not, in fact, provide such benefits.”

2018-Pheromone’s Therapeutic Use in Animals
“It is clear that pheromones play an important role in the regulation of mammalian behavior, so it is plausible that they might have therapeutic value in managing problematic or pathologic behaviors. However, there is little published preclinical evidence on the composition or effects of natural pheromones or synthetic analogues, and what is available comes from proprietary or commercial sources.

Results of clinical studies of these products are mixed. Consistent, replicable evidence of clinically significant effects is not available. No evidence of any harm from pheromone products has been published, and while adverse events seem unlikely, no study has been conducted specifically to look for them.

Available pheromone products are likely safe, but it is unclear what, if any, clinical benefits they may provide for any of the variety of indications for which they are commonly recommended.”

All in all, the evidence for clinical use of pheromones in dogs and cats has not strengthened significantly in the last decade. A new study has been published which purports to support one benefit for dog and cat pheromones, but as is all too common in veterinary research, it has a critical flaw that renders its conclusions unreliable.

Prior MR, Mills DS. Cats vs. Dogs: The Efficacy of Feliway FriendsTM and AdaptilTM Products in Multispecies Homes.Front Vet Sci. 2020;7:399. doi:10.3389/fvets.2020.00399

This study looked at the potential use of both dog and cat commercial pheromone products in reducing undesirable behaviors and promoting desirable ones in households with dogs and cats living together. The authors created a list of such behaviors and a survey instrument for owners to rate their view of the relationship between their dogs and cats. The study then recruited owners, online and through veterinary practices, who felt that there was room for improvement in the relationship between their dogs and cats to test the effects of dog and cat pheromone diffusers.

The owners spent two weeks scoring the behaviors between their dogs and cats. They were then randomly assigned a diffuser emitting either a cat pheromone or a dog pheromone, and they continued scoring these behaviors for an additional four weeks. The owners and investigators didn’t know which type of diffuser each group was using. The results showed a significant increase in desirable behaviors and a significant decrease in undesirable behaviors between the baseline and test period for both pheromones, with no difference between the dog and cat products. 

Seven percent of UK households are estimated to own both a cat and a dog, despite a popular view that the two do not live well together.

Have you spotted the flaw yet? That’s right, there was no placebo control. Both groups got what they believed to be a device to improve their pets’ behaviors, and both groups saw such improvement. This is the perfect design for eliciting a caregiver placebo effect, but it is not a reliable way of testing the efficacy of a behavioral treatment. 

This omission of a routine, standard aspect to any clinical trial is so glaring, it would be hard to imagine the investigators didn’t deliberately choose to omit it. Certainly, the authors were aware that this design could simply be an illustration of a placebo effect, because they address the issue in their discussion:

“There are two obvious possible interpretations of the absence of a significant difference between the treatment groups in these outcomes: either both groups were subject to a similar placebo effect; or both diffuser products were similarly effective.

Unfortunately, their response to this problem is unconvincing. They choose to simply assert, without evidence, that the effect seen was too large to be explained by placebo effects. There was also some suggestion in the data that cats responded more to cat pheromone and dogs more to dog pheromone, which the authors also feel argues against the results being due to placebo effects. However, these post-hoc explanations are just speculation, and it is mystifying that the authors would choose not to include the most basic bias control technique for any clinical study.

Bias, of course, is always an issue in any research study, which is why controls such as placebo groups and blinding are so critical. This study had several potential sources of bias beyond the cognitive biases that could have led to an owner placebo effect. The company selling the products tested had some financial relationship to the study, providing their products for free and paying for the study to be made available as an open-access publication. One of the authors, Dr. Mills, has been a committed advocate of pheromone therapy for many years. While I don’t doubt this is based on his sincere believe in the scientific case for these products, it is well-established that research groups consistently pursuing validation of a particular hypothesis tend to have deep unconscious and conscious biases in favor of that hypothesis. Research from such sources merits careful critical appraisal, particularly when essential bias control tools are not employed.

Bottom Line
This study, unfortunately, does little to clarify the potential value of dog and cat pheromones for behavior problems due to the glaring lack of a placebo group and other potential sources of uncontrolled bias. It is disappointing that despite decades of commercial sale and clinical use of pheromone products, we are still lacking robust, replicated, convincing scientific evidence of their effectiveness. 

While there are likely no direct risks to using such products, I see numerous pet owners and veterinarians turn to them before pursuing appropriate behavioral or pharmacologic therapy for serious behavioral problems. The false impression that these are treatments with solid scientific support does cause indirect harm by delaying or replacing other therapies. Our pets deserve the best treatment possible, and this is always the treatment supported by the strongest evidence. So far, pheromones do not meet this standard.

Posted in Herbs and Supplements | 4 Comments

The SkeptVet Visits the Body of Evidence Podcast

I recently had a chance to chat with Jonathan Jarry and Dr. Christopher Labos on the Body of Evidence Podcast. We covered a wide range of subjects, touching on both evidence-based pet care and alternative medicine. Check it out here!

2:24 Evidence-based veterinary medicine

4:49 Extrapolating from human clinical trials

7:31 Do vets change their mind?

10:07 Acupuncture, homeopathy and chiropractic in the animal world

14:34 Pets and vaccines

17:25 A very special guest appearance

18:00 How to talk to vaccine hesitant pet owners

20:45 The cost of veterinary care

23:11 Placebos

27:52 Raw food diets

32:04 The word “zoopharmacognosy”

32:52 What should dogs and cats eat

37:57 What should dogs and cats NOT eat

40:28 CBD supplements

42:51 Declawing cats

44:17 Inside cat or outside cat

46:02 Supplements to change urine pH

46:40 Feline injection-site sarcomas

48:28 Omega-3s

48:49 Glucosamine

49:23 Cranberry supplements

50:35 New pet parents, take it all with a grain of salt

52:22 The shocking truth about pure breeds

Posted in Presentations, Lectures, Publications & Interviews | 7 Comments