Why do vets not recommend raw diets

By Isabella Storyclaire

last updated September 16, 2024

Contributions sourced from

Why Vets Dont Recommend Raw Diets

Raw diets are currently increasing in popularity. There are many books available which describe how to prepare them, and pre-made commercial options are readily available for purchase. Even so, many veterinarians are not on board with the hype. Both the World Small Animal Veterinary Association and British Veterinary Association discourage raw feeding. So why not?

Here are some of the reasons many veterinarians will not recommend raw diets:

Raw food prep can introduce bacteria into the home

The surface of any raw meat can carry bacteria. Even commercially prepared pet foods have been shown to carry pathogens. They can also easily be spread around the home if we arent careful when preparing our pets raw food. Dishes used to serve raw foods have to be properly cleaned and disinfected after each use. Young children and immunocompromised individuals are at risk of falling ill even when very low numbers of infectious bacteria are present.

Bacteria found on the surface of raw meats can infect pets and people

Infections caused by bacteria found on raw meat can cause diarrhoea, hospitalisation, and death in both people and pets. Although it appears that cats and dogs are sometimes able to carry pathogenic bacteria without showing clinical signs, they are still able to pass them on to the people they live with. It has been documented that pathogenic and antibiotic-resistant bacteria are shed in the droppings of dogs and cats.

There are reported cases of raw diets causing illness in pets and people

One example was thoroughly documented and published in a scientific journal. In 2018, a raw cat food was linked with tuberculosis in the gut; a very rare form of the disease. One hundred and thirty cats throughout the UK were diagnosed with an infection. It was very likely that the cats picked up the infection from their commercial food as they lived indoors and were consuming the same batch of raw food. There were no other potential sources of infection identified. In the end, a total of five people in contact with the infected cats also contracted tuberculosis, with one requiring medical treatment.

Lack of evidence demonstrating the benefits of raw diets

Research investigating the true benefits of feeding dogs a raw diet is still in its infancy. Dog owners who feed raw diets often report a link between raw-feeding with improved health. This includes beliefs that a raw diet will make a dogs coat shiny, enhance muscle condition and improve teeth cleanliness. However, more scientifically rigorous methods would be required to draw definitive conclusions. Until then, it appears that the risks of feeding a raw diet are greater than the potential benefits they would provide.

Nutrient inadequacies in home-prepared raw diets

Many people have taken it upon themselves to formulate raw meals for their pets. Unfortunately, this can lead to many nutrient deficiencies and imbalances. Even the majority of published recipes have ambiguous instructions which make them inconsistent or are not formulated with a proper nutrient balance in the first place. When looking for recipes to cook at home, the best source is from a board-certified veterinary nutritionist. They will have the expertise to formulate a diet and can tailor the nutrient profile to closely match your dogs specific needs.

Conclusion

Every veterinary surgeon will adhere to the first rule of care: first do no harm. Many vets believe that recommending feeding a raw diet goes against this principle, especially because of the lack of research demonstrating the benefits.

At the end of the day, your vets recommendations will be made to safeguard the wellbeing of your pet while being mindful of any public health implications.

References

Dgi, J., Imre, K., Herman, V., Bucur, I., Radulov, I., Petrec, O. C., & Cristina, R. T. (2021). Antimicrobial Drug-Resistant Salmonella in Urban Cats: Is There an Actual Risk to Public Health?. Antibiotics, 10(11), 1404.
Empert-Gallegos, A., Hill, S., & Yam, P. S. (2020). Insights into dog owner perspectives on risks, benefits, and nutritional value of raw diets compared to commercial cooked diets. PeerJ, 8, e10383.
Morelli G, Bastianello S, Catellani P, Ricci R. (2019) Raw meat-based diets for dogs: survey of owners motivations, attitudes and practices. BMC veterinary research. 2019 Dec;15(1):1-0.
OHalloran C, TrnqvistJohnsen C, Woods G, Mitchell J, Reed N, Burr P, GascoyneBinzi D, Wegg M, Beardall S, Hope J, GunnMoore D. (2021) Feline tuberculosis caused by Mycobacterium bovis infection of domestic UK cats associated with feeding a commercial raw food diet. Transboundary and Emerging Diseases. 2021 Jul;68(4):2308-20.
Runesvrd, E., Wikstrm, C., Fernstrm, L. L., & Hansson, I. (2020). Presence of pathogenic bacteria in faeces from dogs fed raw meatbased diets or dry kibble. Veterinary Record, 187(9), e71-e71.
Wilson SA, Villaverde C, Fascetti AJ, Larsen JA. (2019) Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats. Journal of the American Veterinary Medical Association. 2019 May 15;254(10):1172-9.

Debating raw diets

By Brennen McKenzie, MA, MSc, VMD, cVMA

In spite of resistance from most veterinarians and from public health authorities, the popularity of raw meat-based diets for dogs and cats continues to grow.^1,2 Raw feeders have a range of ideas about nutrition, but they typically believe that raw diets are healthier and more natural than cooked diets, and they often suspect conventional commercial diets are unsafe or a possible cause of disease.^3,4

Unfortunately, it is not only pet owners who hold such beliefs. Though they are a minority, some veterinarians promote raw feeding and attack the safety and nutritional value of cooked commercial diets.^5,6

Surveys show that pet owners who feed raw diets are less likely to trust nutrition advice from veterinarians and are also less likely to adhere to other recommendations (e.g. vaccination and parasite prevention) than owners who feed traditional commercial diets.^3,1 Veterinarians who promote raw feeding and condemn conventional diets are also often suspicious of vaccines and other science-based medical therapies, and frequently advocate alternative medical practices.^5,7,8

Though individual beliefs vary, there is a general trend for raw diets to be appealing to pet owners or veterinarians who believe more natural diets and medical approaches are safer and better than conventional medical and nutritional practices. These beliefs are predicated on questionable concepts and are not supported by convincing research evidence.

Arguments for raw diets

The most common rationale for feeding raw is that this is a more natural diet to which dogs and cats have been adapted by evolution and which should, therefore, be healthier for them. Taxonomically, dogs and cats are carnivores (though dogs are functionally omnivores) and their ancestors ate live prey and carrion, so they must be designed for a diet as close as possible to that of wild carnivores. Some raw-diet advocates extend this argument by claiming that anatomic and physiological similarities between domestic dogs and wolves imply dogs should be fed the same diet wolves eat in the wild and domestic cats should ideally eat whole prey as wild felines do.⁵

Raw diets are also claimed to have specific health effects ranging from better coat and stool quality to a lower risk of diabetes, allergies, cancer, and other serious diseases.^8,9 Proponents of raw diets consistently argue that any risks are outweighed by these benefits.

The other major argument for feeding raw diets is that cooked commercial diets are nutritionally inadequate and unhealthy. Proponents of raw diets express concerns about the loss of nutrients in heating and processing, the dangerous health effects of grains and carbohydrates in commercial diets, and numerous purported toxins, ranging from by-products of processing to preservatives and other additives in canned and dry diets. Many chronic health problems are blamed on commercial pet food by raw-diet advocates.^5,6,8

The evidence

The idea raw diets should be beneficial because they are natural is simply an expression of the appeal to nature fallacy, the misconception that anything found in nature is inherently healthier than anything produced by humans. Illustrations of why this is false are easy to find. Consider, for example, that dysentery, smallpox, and rattlesnake venom are perfectly natural, and antibiotics, vaccines, and anti-venin are clearly artificial, yet theres no doubt the latter are certainly better for health than the former.

It is also clear natural is not a synonym for healthy from the fact that parasitism, malnutrition, and infectious disease are rampant in wild animal populations and that life expectancy and health are nearly always superior for animals in appropriate captive environments.¹⁰ The diet of wild carnivores is simply the food they can get, not a perfect diet designed for long-term health. Experts in captive wild carnivore nutrition recommend commercial foods as a significant component of the overall diet for these species because such foods improve the safety and nutritional quality of the diet and the health ofthese animals.¹¹¹⁴

Even if a species-typical diet in the wild were optimal for the health of wild carnivores, it is obvious dogs, at least, have evolved far from their wild ancestors and would not necessarily have the same dietary needs. Evidence shows many genetic, anatomic, and physiologic differences between domestic dogs and wild canids that result from selective pressures associated with living with humans, and these have altered their nutritional requirements and the foods that will best support long-term health.¹⁵¹⁹

There is no compelling evidence for any of the specific health benefits claimed for raw diets, and there has been very little research investigating them.^4,20 The few published studies of raw feeding have found various effects on physiologic and clinical parameters, but little sign of any significant health effects, so most health claims are purely anecdotal at this point.²¹²⁵

The claims about the hazards of commercial diets vary from implausible and completely unproven to legitimate, substantiated risks. Commercial diets can be a source of infectious diseases, and some cases of serious injury due to adulterants or other toxins have been seen.^26,27 However, there is ample research evidence to support the nutritional value of properly formulated diets, and some evidence to support specific health benefits for some diets, such as renal and urolith dissolution diets.²⁸³⁰ Millions of dogs and cats live long and healthy lives on commercial pet foods, so while they are not perfect or risk free, there is little reason to believe they are a major risk factor for disease in most animals, and there is certainly no research evidence to support this claim.

The risks of raw diets

Unlike the benefits of raw diets, which are theoretical and unproven, the risks are well documented. Commercial raw diets that meet Association of American Feed Control Officials (AAFCO) standards are likely to be nutritionally complete, but many raw advocates feed home-prepared diets, and these diets are frequently nutritionally unbalanced and incomplete.^4,3135 The widespread use of bones in raw diets also presents a significant risk of dental fractures and gastrointestinal injury,³⁶⁴⁰ though one study has suggested some possible benefits for dental health.⁴¹ Even wild carnivores are at risk for acute dental and gastrointestinal trauma from bones, as well as chronic tooth wear, and this can lead to the natural outcomes of suffering or death.⁴²⁴⁴ Pet dogs and cats are at least as susceptible to this risk as wild carnivores, and the natural outcomes are clearly unacceptable to owners.

The most significant risk of raw diets is from food-borne infectious disease. Illness and death in cats and dogs, and in their owners, have been caused by pathogens found in raw pet diets.^4,4551 Although such pathogens can contaminate cooked diets as well, the risk is significantly higher for raw foods.²⁷ While healthy, immunocompetent adult pets may be able to resist these organisms to some extent, there is no absolute immunity in dogs and cats to food-borne illness. Young, old, immunosuppressed animals, and their human caregivers, are at even higher risk.

Bottom line

There are no proven health benefits to raw diets, and most of the claims rest on dubious theoretical grounds and exaggerated fears about conventional cooked diets. There are, however, clear risks to feeding raw meat, including nutritional deficiencies or excesses, risk of injury from bones, and risk of severe infection and death in both pets and humans. While properly formulated raw diets can be nutritionally appropriate and the risks of infectious disease can be mitigated by scrupulous food handling, the established risks of raw diets and the complete lack of compelling evidence for any health benefits make the use of such diets a choice based on ideology or personal belief, not sound scientific evidence.

References¹ 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 October 27, 2018.² Waters A. Raw diets: are we at a turning point? Vet Rec. 2017;181(15):384.2-384. doi:10.1136/vr.j4709³ 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.3031⁴ 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.243.11.1549⁵ Billinghurst I. Give Your Dog a Bone.; 1993. https://www.worldcat.org/title/give-your-dog-a-bone/oclc/973482033&referer=brief_results. Accessed October 27, 2018.⁶ Lonsdale T. Raw Meaty Bones. [NSW Australia]: Rivetco P/L; 2001. https://www.worldcat.org/title/raw-meaty-bones-promote-health/oclc/1040658362&referer=brief_results. Accessed October 27, 2018.⁷ Pitcairn RH, Pitcairn SH. Dr. Pitcairns Complete Guide to Natural Health for Dogs & Cats.; 2017. https://www.worldcat.org/title/dr-pitcairns-complete-guide-to-natural-health-for-dogs-cats/oclc/948336415&referer=brief_results. Accessed October 27, 2018.⁸ Dodds WJ, Laverdure D. Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health.; 2015. https://www.worldcat.org/title/canine-nutrigenomics-the-new-science-of-feeding-your-dog-for-optimum-health/oclc/890808034&referer=brief_results. Accessed October 27, 2018.⁹ Billinghurst I. Pointing the Bone at Cancer: In Dogs Cats and Humans.; 2016. https://www.worldcat.org/title/pointing-the-bone-at-cancer-in-dogs-cats-and-humans/oclc/964572415&referer=brief_results. Accessed October 27, 2018.¹⁰ Tidire M, Gaillard J-M, Berger V, et al. Comparative analyses of longevity and senescence reveal variable survival benefits of living in zoos across mammals. Sci Rep. 2016;6(1):36361. doi:10.1038/srep36361¹¹ Newton. Nutrition. In: Mexican Wolf Husbandry Manual. Silver Springs, MD: American Association of Zoos and Aquariums; 1995. https://nagonline.net/wp-content/uploads/2013/12/Red-Wolf-Nutrition.pdf.¹² Waddell W. Nutrition. In: Red Wolf Husbandry Manual Guidelines for Captive Management. Silver Springs, MD: American Association of Zoos and Aquariums; 1998. https://nagonline.net/wp-content/uploads/2013/12/Red-Wolf-Nutrition.pdf.¹³ Allen M. Maned wolf nutritional management. In: Husbandry Manual for the Maned Wolf Chrysocyon Brachyurus. Silver Springs, MD: American Association of Zoos and Aquariums; 1995.¹⁴ AZA Canid Tag. Large Canid (Canidae) Care Manual. Silver Springs, MD: American Association of Zoos and Aquariums; 2012. https://nagonline.net/wp-content/uploads/2014/05/Large-Canid-Care-Manual-2012-NAG-EDIT.pdf.¹⁵ Vil C, Maldonado JE, Wayne RK. Phylogenetic relationships, evolution, and genetic diversity of the domestic dog. J Hered. 90(1):71-77. http://www.ncbi.nlm.nih.gov/pubmed/9987908. Accessed October 27, 2018.¹⁶ Wayne RK. Molecular evolution of the dog family. Trends Genet. 1993;9(6):218-224. http://www.ncbi.nlm.nih.gov/pubmed/8337763. Accessed October 27, 2018.¹⁷ Serpell J, Barrett P. The Domestic Dog: Its Evolution, Behavior and Interactions with People. Second edition.; 2017. https://www.worldcat.org/title/domestic-dog-its-evolution-behavior-and-interactions-with-people/oclc/987274028&referer=brief_results. Accessed October 27, 2018.¹⁸ 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/nature11837¹⁹ Reiter T, Jagoda E, Capellini TD. Dietary Variation and Evolution of Gene Copy Number among Dog Breeds. 2016. doi:10.1371/journal.pone.0148899²⁰ Schlesinger D, Joffe D. Raw Food Diets in Companion Animals: A Critical Review. Can Vet J. 2011;52(1):50-4.²¹ Vester BM, Burke SL, Liu KJ, Dikeman CL, Simmons LG, Swanson KS. Influence of feeding raw or extruded feline diets on nutrient digestibility and nitrogen metabolism of African wildcats (Felis lybica). Zoo Biol. 2010;29(6):676-686. doi:10.1002/zoo.20305²² Kerr KR, Vester Boler BM, Morris CL, Liu KJ, Swanson KS. Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets. J Anim Sci. 2012;90(2):515-522. doi:10.2527/jas.2010-3266²³ Beloshapka AN, Duclos LM, Vester Boler BM, Swanson KS. Effects of inulin or yeast cell-wall extract on nutrient digestibility, fecal fermentative end-product concentrations, and blood metabolite concentrations in adult dogs fed raw meatbased diets. Am J Vet Res. 2012;73(7):1016-1023. doi:10.2460/ajvr.73.7.1016²⁴ Kim J, An J-U, Kim W, Lee S, Cho S. Differences in the gut microbiota of dogs (Canis lupus familiaris) fed a natural diet or a commercial feed revealed by the Illumina MiSeq platform. Gut Pathog. 2017;9(1):68. doi:10.1186/s13099-017-0218-5²⁵ Sandri M, Dal Monego S, Conte G, Sgorlon S, Stefanon B. Raw meat based diet influences faecal microbiome and end products of fermentation in healthy dogs. BMC Vet Res. 2017;13(1):65. doi:10.1186/s12917-017-0981-z²⁶ Bischoff K, Rumbeiha WK. Pet Food Recalls and Pet Food Contaminants in Small Animals. Vet Clin North Am Small Anim Pract. 2018;48(6):917-931. doi:10.1016/j.cvsm.2018.07.005²⁷ Nemser SM, Doran T, Grabenstein M, et al. Investigation of Listeria, Salmonella, and toxigenic Escherichia coli in various pet foods. Foodborne Pathog Dis. 2014;11(9):706-709. doi:10.1089/fpd.2014.1748²⁸ Council NR. Nutrient Requirements of Dogs and Cats. Washington, D.C.: National Academies Press; 2006. doi:10.17226/10668²⁹ Association of American Feed Control Officials. 2018 Official Publication: Association of American Feed Control Officials Incorporated.; 2018. https://www.worldcat.org/title/2018-official-publication-association-of-american-feed-control-officials-incorporated/oclc/1023038973&referer=brief_results. Accessed October 27, 2018.³⁰ Davies M. Veterinary clinical nutrition: success stories: an overview. Proc Nutr Soc. 2016;75(03):392-397. doi:10.1017/S002966511600029X³¹ Taylor MB, Geiger DA, Saker KE, Larson MM. Diffuse osteopenia and myelopathy in a puppy fed a diet composed of an organic premix and raw ground beef. J Am Vet Med Assoc. 2009;234(8):1041-1048. doi:10.2460/javma.234.8.1041³² Freeman LM, Michel KE. Veterinary Medicine Today Timely Topics in Nutrition Evaluation of raw food diets for dogs. J Am Vet Med Assoc. 2001;218(5):705-709. doi:10.2460/javma.2001.218.705³³ Lauten SD, Smith TM, Kirk CA, Bartges JW, Adams A WS. Computer Analysis of Nutrient Sufficiency of Published Home-Cooked Diets for Dogs and Cats. In: Proceedings of the American College of Veterinary Internal Medicine Forum. Baltimore, MD; 2005.³⁴ Stockman J, Fascetti AJ, Kass PH, Larsen JA. Evaluation of recipes of home-prepared maintenance diets for dogs. J Am Vet Med Assoc. 2013;242(11):1500-1505. doi:10.2460/javma.242.11.1500³⁵ Larsen JA, Parks EM, Heinze CR, Fascetti AJ. Evaluation of recipes for home-prepared diets for dogs and cats with chronic kidney disease. J Am Vet Med Assoc. 2012;240(5):532-538. doi:10.2460/javma.240.5.532³⁶ Robinson J, Gorrel C. The oral status of a pack of foxhounds fed a natural diet. In: Proceedings. Fifth World Veterinary Dental Congress. Birmingham, England; 1997.³⁷ Rousseau A, Prittie J, Broussard JD, Fox PR, Hoskinson J. Incidence and characterization of esophagitis following esophageal foreign body removal in dogs: 60 cases (1999?2003). J Vet Emerg Crit Care. 2007;17(2):159-163. doi:10.1111/j.1476-4431.2007.00227.x³⁸ Gianella P, Pfammatter NS, Burgener IA. Oesophageal and gastric endoscopic foreign body removal: complications and follow-up of 102 dogs. J Small Anim Pract. 2009;50(12):649-654. doi:10.1111/j.1748-5827.2009.00845.x³⁹ Frowde PE, Battersby IA, Whitley NT, Elwood CM. Oesophageal disease in 33 cats. J Feline Med Surg. 2011;13(8):564-569. doi:10.1016/j.jfms.2011.04.004⁴⁰ Thompson HC, Cortes Y, Gannon K, Bailey D, Freer S. Esophageal foreign bodies in dogs: 34 cases (2004-2009). J Vet Emerg Crit Care. 2012;22(2):253-261. doi:10.1111/j.1476-4431.2011.00700.x⁴¹ Marx F, Machado G, Pezzali J, et al. Raw beef bones as chewing items to reduce dental calculus in Beagle dogs. Aust Vet J. 2016;94(1-2):18-23. doi:10.1111/avj.12394⁴² Steenkamp G, Gorrel C. Oral and Dental Conditions in Adult African Wild Dog Skulls: A Preliminary Report. J Vet Dent. 1999;16(2):65-68. doi:10.1177/089875649901600201⁴³ Van Valkenburgh B. Incidence of Tooth Breakage Among Large, Predatory Mammals. Am Nat. 1988;131(2):291-302. doi:10.1086/284790⁴⁴ VanValkenburgh B, Hertel F. Tough Times at La Brea: Tooth Breakage in Large Carnivores of the Late Pleistocene. Science (80- ). 1993;261(5120):456-459. doi:10.1126/science.261.5120.456⁴⁵ 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, 2018.⁴⁶ Investigation into an Outbreak of Shiga Toxin Producing Escherichia Coli (STEC) O157 PT 21/28 Stx2 in England.; 2017. www.facebook.com/PublicHealthEngland. Accessed October 27, 2018.⁴⁷ Chengappa MM, Staats J, Oberst RD, Gabbert NH, McVey S. Prevalence of Salmonella in Raw Meat used in Diets of Racing Greyhounds. J Vet Diagnostic Investig. 1993;5(3):372-377. doi:10.1177/104063879300500312⁴⁸ Finley R, Ribble C, Aramini J, et al. The risk of salmonellae shedding by dogs fed Salmonella-contaminated commercial raw food diets. Can Vet J = La Rev Vet Can. 2007;48(1):69-75. http://www.ncbi.nlm.nih.gov/pubmed/17310625. Accessed October 27, 2018.⁴⁹ Joffe DJ, Schlesinger DP. Preliminary assessment of the risk of Salmonella infection in dogs fed raw chicken diets. Can Vet J = La Rev Vet Can. 2002;43(6):441-442. http://www.ncbi.nlm.nih.gov/pubmed/12058569. Accessed October 27, 2018.⁵⁰ Weese JS, Rousseau J, Arroyo L. Bacteriological evaluation of commercial canine and feline raw diets. Can Vet J = La Rev Vet Can. 2005;46(6):513-516. http://www.ncbi.nlm.nih.gov/pubmed/16048011. Accessed October 27, 2018.⁵¹ Strohmeyer RA, Morley PS, Hyatt DR, Dargatz DA, Scorza AV, Lappin MR. Evaluation of bacterial and protozoal contamination of commercially available raw meat diets for dogs. J Am Vet Med Assoc. 2006;228(4):537-542. doi:10.2460/javma.228.4.537

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. He has served as president of the Evidence-Based Veterinary Medicine Association and reaches out to the public through his SkeptVet blog, the Science-Based Medicine blog, and more. He is certified in medical acupuncture for veterinarians. Columnists opinions do not necessarily reflect those of Veterinary Practice News.