Food is love—So why is nutrition a problem area for veterinarians?

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 in 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, food-induced dance. Every feeding was a celebration for Snoopy, 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 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 is also something over which we have control. We naturally want to do everything we can to ensure our pets stay healthy, but many factors influencing the risk of disease are beyond our control. Food, at least, is something tangible 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 well-being. 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; the desire to find the perfect food to guarantee our pets good health is all too easily exploited 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 veterinarians for guidance about nutrition, and do we live up to our responsibility to provide it? Do clients trust us? Unfortunately, the idea veterinarians are unreliable 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 veterinarians 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 our patients’ health. In general, the public sees veterinarians as pretty trustworthy and likeable, sometimes even more so that other health-care professionals.1 While there is some variability among studies in the extent to which pet owners trust our advice about nutrition, most show a majority of clients desire advice from their veterinarian 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 nontraditional diets rather than commercial pet food express less confidence in veterinary nutrition advice.4,7,8 One study found 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 percent of clients who did not feed raw trusted this advice “very much,” while only 13 percent 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 percent of clients who did not feed raw products, but by only 36 percent of those clients who did.4 Raw feeders are less likely to trust veterinary recommendations about vaccination, flea control, and other preventive health interventions.4,9 This suggests 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 percent of raw feeders trusted veterinary advice in general “somewhat,” and 32 percent had this level of confidence in the nutrition knowledge of their veterinarian.4 Surprisingly, among cat owners, a majority reported choosing to feed raw was influenced by advice from their veterinarian (58 percent) or from other veterinary sources (78 percent).4 This suggests the problem may not necessarily be a true lack of trust in veterinarians as a source of nutritional advice so much as a desire to follow veterinary guidance only when it is consistent with clients’ 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 veterinarians with alternative philosophies or approaches, and raw feeders are likely to trust such veterinarians 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 toward 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 have 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 influencing these recommendations. Should clients trust us? The arguments against heeding veterinary advice about nutrition are ultimately bad arguments that 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 we have to address to protect our clients from being misled. Consider the following: What do veterinarians know about nutrition? The idea veterinarians (or at least those practicing conventional science-based medicine) know nothing about nutrition is false. All veterinarians learn about the importance of nutrition in veterinary school and about the effect of food and feeding practices on health. Some of this knowledge is gained 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 the quantity and quality of the nutrition education most veterinarians 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 prepares us to offer sound advice about nutrition to our clients. Crucially, the alternative sources 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 laypersons with little or no scientific training, along with the information jungle that is the internet, cannot provide the quality or reliability of advice about nutrition we can as veterinarians. Proponents of unconventional feeding practices, including many veterinarians committed to alternative medical approaches, will tell clients and conventional veterinarians 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 that lack scientific validation but conform to the biases these advocates bring to their search. The claim 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—there are 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 additives,45 and many other such ideas are frequently identified as examples of advanced knowledge or understanding most veterinarians 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 the pet food industry has a biased perspective on pet nutrition, and that this industry has entirely too much influence on both veterinary education and the profession. The giving of gifts from industry representatives has been clearly linked to prescribing behavior in physicians,46,47 and it is unlikely 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 our clients’ trust. Such practices should absolutely be discouraged. Similarly, there is good evidence industry funding influences the outcomes of clinical research in ways that are often in favor of the funder’s products.48,49 The concern 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 bias,50 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, nonprofit 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 these legitimate concerns about bias in the information veterinarians receive from industry and provide to our clients concerning pet nutrition validates neither dismissing veterinary advice nor turning to alternative information sources. We cannot simply declare all nutrition research worthless due to industry bias and make up whatever alternative theories or facts that 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 the funding source, and that this influences research results as much or more than where the money comes from.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 diets,52–54 for example, were recently strongly challenged in a narrative literature review.55 This analysis 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 for the sort of claims offered by those who assert 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 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 veterinarians care more about selling food than patient health? I suspect no one will be surprised 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 health-care providers, the idea 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 prone to believing veterinarians 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 veterinarians 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 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 disease.65 As general practitioners, our fundamental understanding of physiology and nutrition is sound and useful, even though we are not nutrition specialists. The same can be said regarding our understanding of heart disease and diabetes—it is sound and useful even though we are not board-certified 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 guaranteeing only good health for 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 about individual 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 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 health-care professionals that 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 to which our clients may be exposed. 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 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 advice is not to cede the field, but to work harder to meet our responsibilities to our clients and our patients. Brennen McKenzie, MA, MSc, VMD, cVMA, discovered evidence-based veterinary medicine after attending the University of Pennsylvania School of Veterinary Medicine and working as a small animal general practice veterinarian. 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