FAQ: Nutrients

Pet Feeding Philosophies

Pet Feeding Philosophies

Alternative feeding philosophies—such as vegetarian, raw, or homemade diets—are gaining interest among dog and cat owners for reasons ranging from perceived naturalness and health benefits to ethical or sustainability concerns. However, these approaches vary widely in their ability to meet pets’ nutritional requirements and may carry important safety risks. This FAQ collection explores common questions surrounding these feeding philosophies to support informed, evidence-based discussions between veterinary professionals and pet owners.

TABLE OF CONTENTS

Vegetarian Diets for Dogs and Cats

Are vegetarian diets appropriate for cats and dogs?

Complete and balanced diets, foods that provide all the essential nutrients a pet needs in the correct amounts and ratios relative to one another, can be formulated using ingredients derived from plant or animal tissues or synthetically produced.

Complete and balanced vegetarian pet food can be made, but care must be taken to address the unique dietary requirements of dogs and, especially, of cats. Research has found nutritionally deficient vegetarian diets for both cats and dogs.1–5 To ensure that a vegetarian cat or dog food is complete and balanced, it is critical that it be formulated by a qualified nutritionist.

What is unique about the dietary requirements of cats?

Cats are obligate carnivores and require specific nutrients found most abundantly in animal tissues and lacking in purely plant-based diets:1

  • Arachidonic acid—Cats lack sufficient activity of the pathway that converts linoleic acid to arachidonic acid.6
  • Taurine—Unlike dogs, cats cannot produce enough taurine from other amino acids to satisfy their needs.6
  • Vitamin A—Unlike dogs, cats lack sufficient levels of the enzyme that converts vitamin A precursors (e.g., beta-carotene) to active vitamin A.6
  • Vitamin B3 (niacin)—Although dogs can derive some niacin from conversion of tryptophan, cats cannot. Both species benefit from a dietary source.6

These unique requirements lead to greater challenges in formulating a complete and balanced vegetarian diet for cats. To meet the unique needs of cats, a vegetarian diet must be supplemented with key nutrients not present in adequate quantities in vegetarian ingredients.

Is feeding a vegetarian diet indicated in some cases?

There is no scientific evidence that vegetarian diets provide added health benefits to healthy pets.7,8 However, dogs with the following conditions might benefit from eating a vegetarian diet:

  • Confirmed allergy to multiple animal-source proteins that cannot be fed a hydrolyzed animal-source protein diet.
  • History or risk of urate or cystine urolithiasis—to reduce excretion of purines (urate precursors found in high amounts in organ tissues and fish) and methionine (a cystine precursor found in high levels in animal proteins).9
  • Hepatic encephalopathy (HE) or risk of HE—non-meat protein sources, such as soy or dairy, are better tolerated in patients with portosystemic shunts at risk for hepatic encephalopathy.10

 

References

Homemade Pet Foods

What is a complete and balanced diet?

A diet is considered complete and balanced when it meets government nutritional requirements which ensure safe and proper nutrition for healthy pets. The Association of American Feed Control Officials (AAFCO) and the European Pet Food Industry (FEDIAF) are the main authorities that define “complete and balanced diets” and “complete pet foods” in the U.S. and Europe, respectively. These authorities define complete and balanced pet foods as being formulated to provide sufficient daily levels of essential nutrients for pets1 at their particular life stage.2,3

Why should I look for “complete and balanced” or “complete pet food” on my pet food label?

Feeding a complete and balanced diet assures owners that they are meeting the nutritional needs of their pet for their particular life stage,2,3 without the need for additional supplementation. Pet food labels that do not state they are “complete and balanced” or “complete pet food” may not meet adequate or safe nutrient standards of a properly formulated diet under government regulations. This includes both under- and over-feeding of essential nutrients.

Why isn’t a homemade diet healthier for my pet?

Recipes for homemade pet foods are readily accessible to pet owners via many sources. While nutritional balance can be achieved in a homemade diet with specific formulation by a veterinary nutritionist, it is often unrealistic for most pet owners to achieve. Often, nutritional balance of homemade diets is compromised by compliance to the recipe by the pet owner,4 a supply of consistent ingredients with known nutritional composition, and/or access to laboratory analyses that ensure adequate delivery of nutrients. As a result of these complexities, homemade diets often have nutrient deficiencies, even with vitamin and mineral supplementation.5,6 

The vast majority of homemade recipes are lacking in essential nutrients7 with studies showing >95% of adult canine recipes8,9 and 100% of adult feline recipes10 deficient in at least one essential nutrient. This is especially concerning because pets’ bodies cannot synthesize required essential nutrients on their own. Therefore, they must be provided by the diet to meet pets’ nutritional needs.

The most prevalent nutrient deficiencies in homemade pet recipes (in descending order):

  • Dogs8—Zinc, choline, vitamin D, copper, EPA + DHA, vitamin E, and calcium
  • Cats10—Choline, iron, thiamine, zinc, manganese, vitamin E, copper, folic acid, calcium, and vitamin D

Unlike humans, dogs and cats cannot synthesize vitamin D from UV exposure. That makes vitamin D an essential nutrient that must be provided by the diet.11

Do I have to worry about my pet’s treats being “complete and balanced?”

Some pet foods and other items for pets, such as treats, are not intended to be a pet’s only source of nutrition.2 As such, they may not be labeled “complete and balanced.” These products are intended to be complementary to a complete and balanced diet1–3 and not the sole source of nutrition for a pet. Limiting food items that are not complete and balanced to less than 10% of a pet’s total caloric intake will help them maintain a healthy weight.12

 

References

Raw Food Diets

What are the nutritional benefits of feeding raw diets?

The idea that raw food diets mimic foods eaten by wolves or wild cats appeals to many pet owners. However, raw food diets may not be optimal for domestic dogs and cats living long, healthy lives in a home environment.1 

Properly formulated raw diets may be nutritionally appropriate, but study after study shows that homemade diets often have nutrient deficiencies2–4 that can lead to health problems such as: 

  • Skeletal and developmental defects in puppies5,6
  • Taurine deficiency in heart muscle in 70% of kittens on raw rabbit diets7
  • Hyperthyroidism in dogs fed diets that included raw beef gullet8

In fact, approximately 80% of recipes for homemade diets have multiple nutrient deficiencies.4

Raw meats are highly digestible, which often results in good stool quality. However, when pet foods are cooked at appropriate temperatures, the digestibility of proteins and grains can be increased—and pose fewer health risks.7,9,10

My pet looks healthy. Why do you emphasize the risks of raw diets?

Studies show that the risks of feeding raw diets are often seriously underestimated.11

Bacterial contamination is more often linked with raw meat-based diets than with heat-treated foods,12–14 and this is a proven risk factor for pets to pass pathogens into the environment via feces.15–17 These environmental pathogens are considered even greater risks for young children, elderly or immunocompromised people.15–17

Medical reports of pets sickened by these bacteria refute the idea that dogs and cats are naturally adapted to the bacteria in raw diets.17–19 These diets can change a pet’s gut microbiome in ways similar to GI diseases.20

Although one study suggested that chewing bones helped remove pets’ dental plaque,21 many more studies found that when bones are included in raw diets pets are at greater risk for broken teeth, choking or a perforated intestinal tract that could lead to fatal complications.22–25

 

References

References

Vegetarian Diets for Dogs and Cats

  1. Gray, C. M., Sellon, R. K., & Freeman, L. M. (2004). Nutritional adequacy of two vegan diets for cats. Journal of the American Veterinary Medical Association, 225(11), 1670–1675.
  2. Kanakubo, K., Fascetti, A. J., & Larsen, J. A. (2015). Assessment of protein and amino acid content ratios and labelling adequacy of commercial vegetarian diets formulated for dogs and cats. Journal of the American Veterinary Medical Association, 247(4), 385–392.
  3. Fantinati, M., Dufayet, R., Rouch-Buck, P., & Priyemenko, N. (2021). Relationship between a plant-based ‘vegan’ pet food and clinical manifestations of multiple nutrient deficiencies in two cats. Journal of Animal Physiology and Animal Nutrition, 105(6), 1179–1191. doi: 10.1111/jpn.13510
  4. Zafalon, R. V. A., Risolia, L. W., Vendramini, T. H. A., Rodrigues, R. B. A., Pedrinelli, V., Texeira, F. A., Rentas, M. F., Perini, M. P., Alvarenga, I. C., & Brunetto, M. A. (2020). Nutritional inadequacies in commercial vegan foods for dogs and cats. PLoS ONE, 15(1), e0227046. doi: 10.1371/journal.pone.0227046
  5. Dodd, S. A. S., Shoveller, A. K., Fascetti, A. J., Yu, Z. Z., Ma, D. W. L., & Verbrugghe, A. (2021). A comparison of key essential nutrients in commercial plant-based pet foods sold in Canada to American and European canine and feline dietary recommendations. Animals, 11(8), 2348. doi: 10.3390/ani11082348
  6. National Research Council. (2006). Nutrient requirements of dogs and cats. National Academies Press.
  7. Dodd, S. A. S., Cave, N. J., Adolphe, J. L., Shoveller, A. K., & Verbrugghe, A. (2019). Plant-based (vegan) diets for pets: A survey of pet owner attitudes and feeding practices. PLoS ONE, 14(1), e0210806.
  8. Brown, W. Y., Vanselow, B. A., Redman, A. J., & Pluske, J. R. (2009). An experimental meat-free diet maintained haematological characteristics in sprint-racing sled dogs. British Journal of Nutrition, 102, 1318–1323.
  9. Lulich, J. P., Berent, A. C., Adams, L. G., Westropp, J. L., Bartges, J. W., & Osborne, C. A. (2016) ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats. Journal of Veterinary Internal Medicine, 30, 1564–1574.
  10. Lidbury, J. A., Cook, A. K., & Steiner, J. M. (2016). Hepatic encephalopathy in dogs and cats. Journal of Veterinary Emergency and Critical Care, 26(4), 471–487.

Homemade Pet Foods

  1. FEDIAF (The European Pet Food Industry). (2019). Code of Good Labelling Practice for Pet Food (pp. 7). Retrieved from https://europeanpetfood.org/wp-content/uploads/2022/02/FEDIAF_labeling_code_2019_onlineOctober2019.pdf
  2. FDA.gov. (2018). “Complete and Balanced” Pet Food. Retrieved from https://www.fda.gov/animal-veterinary/animal-health-literacy/complete-and-balanced-pet-food
  3. Association of American Feed Control Officials. (2017). Reading labels. Retrieved from https://www.aafco.org/consumers/understanding-pet-food/reading-labels/
  4. Johnson, L. N., Linder, D. E., Heinze, C. R., Kehls, R. L., & Freeman, L. M. (2016). Evaluation of owner experiences and adherence to home-cooked diet recipes for dogs. Journal of Small Animal Practice, 57(1), 23–27. doi: 10.1111/jsap.12412
  5. Michel, K. E. (2006). Unconventional diets for dogs and cats. Veterinary Clinics Small Animal Practice, 36, 1269–1281. doi: 10.1016/j.cvsm.2006.08.003
  6. Remillard, R. (2008). Homemade diets: Attributes, pitfalls, and a call for action. Topics in Companion Animal Medicine, 23(3), 137–142. doi: 10.1053/j.tcam.2008.04.006
  7. Streiff, E. L., Zwischenberger, B., Butterwick, R. F., Wagner, E., Iben, C., & Bauer, J. E. (2002). A comparison of the nutritional adequacy of home-prepared and commercial diets for dogs. Journal of Nutrition, 132, 1698–1700S. doi: 10.1093/jn/132.6.1698S
  8. Stockman, J., Fascetti, A., Kass, P., & Larsen, J. (2013). Evaluation of recipes of home-prepared maintenance diets for dogs. Journal of the American Veterinary Medical Association, 242(11), 1500–1505. doi: 10.2460/javma.242.11.1500
  9. Pedrinelli, V., Zafalon, R. V. A., Rodrigues, R. B. A., Perini, M. P., Conti, R. M. C., Vendramini, T. H. A., de Carvalho Balieiro, J. C., & Brunetto, M. A. (2019). Concentrations of macronutrients, minerals and heavy metals in home-prepared diets for adult dogs and cats. Scientific Reports, 9, 13058. doi: 10.1038/s41598-019-49087-z
  10. Wilson, S. A., Villaverde, C., Fascetti, A. J., & Larsen, J. A. (2019). Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats. Journal of the American Veterinary Medical Association, 254(10), 1172–1179. doi: 10.2460/javma.254.10.1172
  11. National Research Council. (2006). Nutrient requirements of dogs and cats. National Academies Press.
  12. Linder, D. E., & Parker, V. J. (2016). Dietary aspects of weight management in cats and dogs. Veterinary Clinics of North America: Small Animal Practice, 46, 869–882. doi: 10.1016/j.cvsm.2016.04.008

Raw Food Diets

  1. Freeman, L. M., Chandler, M. L., Hamper, B. A., & Weeth, L. P. (2013). Current knowledge about the risks and benefits of raw meat-based diets for dogs and cats. Journal of the American Veterinary Medical Association, 243, 1549–1558.
  2. Dillitzer, N., Becker, N., & Kienzle, E. (2011). Intake of minerals, trace elements and vitamins in bone and raw food rations in adult dogs. British Journal of Nutrition, 106, S53–S56.
  3. Freeman, L. M., & Michel, K. E. (2001). Evaluation of raw food diets for dogs. Journal of the American Veterinary Medical Association, 218, 705.
  4. Stockman, J., Fascetti, A. J., Kass, P. H., & Larsen, J. A. (2013). Evaluation of recipes of home prepared maintenance diets for dogs. Journal of the American Veterinary Medical Association, 242, 1500–1505.
  5. Wilson, S. A., Villaverde, C., Fascetti, A. J., & Larsen, J. A. (2019). Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats. Journal of the American Veterinary Medical Association, 254(10), 1172–1179.
  6. Taylor, M. B., Geiger, D. A., Saker, K. E., & Larson, M. M. (2009). Diffuse osteopenia and myelopathy in a puppy fed a diet composed of an organic premix and raw ground beef. Journal of the American Veterinary Medical Association, 234, 1041–1048.
  7. Hamper, B. A., Bartges, J. W., & Kirk, C. A. (2017). Evaluation of two raw diets vs a commercial cooked diet on feline growth. Journal of Feline Medicine and Surgery, 19(4), 424–434.
  8. Köhler, B., Stengel, C., & Neiger, R. (2012). Dietary hyperthyroidism in dogs. Journal of Small Animal Practice, 53, 182-184.
  9. Kerr, K. R., Vester Boler, B. M., Morris, C. L., Liu, K. J., & Swanson, K. S. (2012). 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. Journal of Animal Science, 90(2), 515–522.
  10. Santé-Lhoutellier, V., Astruc, T., Marinova, P., Greve, E., & Gatellier, P. (2008). Effect of meat cooking on physicochemical state and in vitro digestibility of myofibrillar proteins. Journal of Agriculture and Food Chemistry, 56(4), 1488–1494.
  11. Connolly, K. M., Heinze, C. R., & Freeman, L. M. (2014). Feeding practices of dog breeders in the United States and Canada. Journal of the American Veterinary Medical Association, 245, 669–676.
  12. Hellgren, J., Hästö, L. S., Wikström, C., Fernström, L., & Hansson, I. (2019). Occurrence of Salmonella, Campylobacter, Clostridium and Enterobacteriaceae in raw meat-based diets for dogs. Veterinary Record, 184(14), 42. doi: 10.1136/vr.105199
  13. Nemser, S. M., Doran, T., Grabenstein, M., McConnell, T., McGrath, T., Pamboukian, R., Smith, A. C., Achen, M., … Reimschuessel, R. (2014). Investigation of Listeria, Salmonella, and toxigenic Escherichia coli in various pet foods. Foodborne Pathogens and Disease, 11(9), 706–709.
  14. Strohmeyer, R. A., Morley, P. S., Hyatt, D. R., Dargatz, D. A., Scorza, A. V., & Lappin, M. R. (2006). Evaluation of bacterial and protozoal contamination of commercially available raw meat diets for dogs. Journal of the American Veterinary Medical Association, 228(4), 537–542.
  15. Bojanić, K., Midwinter, A. C., Marshall, J. C., Rogers, L. E., Biggs, P. J., & Acke, E. (2017). Isolation of Campylobacter spp. from client-owned dogs and cats, and retail raw meat pet food in the Manawatu, New Zealand. Zoonoses Public Health, 64(6), 438–449.
  16. van Bree, F. P. J., Bokken, G. C. A. M., Mineur, R., Franssen, F., Opsteegh, M., van der Giessen, J. W. B., Lipman, L. J. A., & Overgaauw, P. A. M. (2018). Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Veterinary Record, 182, 50.
  17. Morley, P. S., Strohmeyer, R. A., Tankson, J. D., Hyatt, D. R., Dargatz, D. A., & Fedorka-Cray, P. J. (2006). Evaluation of the association between feeding raw meat and Salmonella enterica infections at a greyhound breeding facility. Journal of the American Veterinary Medical Association, 228, 1524–1532.
  18. Stiver, S. L., Frazier, K. S., Mauel, M. J., & Styer, E. L. (2003). Septicemic salmonellosis in two cats fed a raw-meat diet. Journal of the American Animal Hospital Association, 39, 538–542.
  19. Kim, J., An, J. U., Kim, W., Lee, S., & Cho, S. (2017). 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 Pathogens, 9, 68.
  20. Schmidt, M., Unterer, S., Suchodolski, J. S., Honneffer, J. B., Guard, B. C., Lidbury, J. A., Steiner, J. M., …Kölle, P. (2018).The fecal microbiome and metabolome differs between dogs fed Bones and Raw Food (BARF) diets and dogs fed commercial diets. PLoS ONE, 13(8), e0201279.
  21. Marx, F. R., Machado, G. S., Pezzali, J. G., Marcolla, C. S., Kessler, A. M., Ahlstrøm, Ø., & Trevizan, L.(2016). Raw beef bones as chewing items to reduce dental calculus in beagle dogs. Australian Veterinary Journal, 94, 18–23.
  22. Gianella, P., Pfammatter, N. S., & Burgener, I. A. (2009). Oesophageal and gastric endoscopic foreign body removal: complications and follow-up of 102 dogs. Journal of Small Animal Practice, 50(12), 649–654.
  23. Rousseau, A., Prittie, J., Broussard, J. D., Fox, P. R., & Hoskinson, J. (2007). Incidence and characterization of esophagitis following esophageal foreign body removal in dogs: 60 cases (1999–2003). Journal of Veterinary Emergency and Critical Care, 17, 159–163.
  24. Thompson, H. C., Cortes, Y., Gannon, K., Bailey, D., & Freer, S. (2012). Esophageal foreign bodies in dogs: 34 cases (2004–2009). Journal of Veterinary Emergency and Critical Care, 22, 253–261.
  25. Van Valkenburgh, B. (1998). Incidence of tooth breakage among large, predatory mammals. American Naturalist, 131(2), 291–302.