What veterinarians should know about 3 unconventional cat diets

Unconventional cat diets and feeding practices are becoming increasingly common. The results of a 2020 study show that while 90% of pet cats are offered a conventional commercial diet, only 32% of these felines exclusively receive a conventional diet. As the most popular unconventional diets, 53% of cats were offered raw foods, and 46% of cats were offered home-prepared foods.¹

That’s why Martha G. Cline, DVM, DACVIM (Nutrition), made the case that veterinary professionals should understand the risks and benefits associated with unconventional diets. She examined the nutritional adequacy of 3 popular diets and provided clinical recommendations in her session presented at the 2022 Atlantic Coast Veterinary Conference in Atlantic City, New Jersey.²

1. Vegan and vegetarian diets

Cline began her review of vegan and vegetarian diets by referencing a study whose results showed that all commercially available vegetarian cat diets are deficient in at least 1 amino acid, and all were deficient in taurine.³ She added that this same study found that 13 of 24 dog and food diets did not meet current labeling requirements of the Association of American Feed Control Officers, casting doubt on label accuracy.³

In examining what it would take to formulate a nutritionally adequate vegan or vegetarian diet, Cline said, “So, is it possible to formulate a diet that is vegan or vegetarian for a cat? Yes, you can absolutely do it. Them eating it might be another issue.” She later added, “…on the rare chance that you do have a client that comes in who is interested in this…I would communicate this to them…emphasizing that are obligate carnivores, [and] really the literature doesn’t support that we actually have good quality products even available for these cats.”

2. Home-prepared diets

Cline said the desire for home-prepared diets (HPD) can be driven by client sentiment, such as avoiding additives and preservatives, enhancing the human-animal bond by cooking for their pet, or simply wanting full control over their pet’s nutrition. A veterinarian can also recommend a HPD due to patient comorbidities such as chronic kidney disease or inflammatory bowel disease.

“A home-prepared diet can absolutely provide complete and balanced nutrition when formulated and prepared properly,” said Cline. The problem, she said, is that clients have many resources available for HBD recipes (eg, online, books, magazines) that vary wildly in safety and nutritional adequacy. “They can be written by people who have no nutrition training whatsoever,” said Cline. “My favorite is the great game breeder in Georgia who worked as…a secretary in a law office, but in her spare time wrote diets for Great Danes.’”² She also cited a study that examined 114 home-prepared diets available online, and all contained nutrient deficiencies, including those written by veterinarians.⁴

Cline recommended that general practitioners consult with a board-certified veterinary nutritionist when formulating diets for their clients. Follow-up consultations should assess adherence to the diet and check for nutrient imbalances.

3. Raw-meat-based diets

Cline explained that raw-meat-based diets (RMBDs), both commercial and home-prepared, can be nutritionally adequate when formulated properly. She said the danger in RMBDs comes from antibiotic resistance and the potential presence of zoonotic pathogens resulting in both human and animal disease.

On antibiotic resistance, she referenced a CDC study of 14 commercially available raw food products in Europe, whose results found that 100% of samples carried enterococci resistant to erythromycin, streptomycin, chloramphenicol, and tetracycline.⁵ “The really big concern, and the reason why this study was done, is because these researchers from the CDC concluded that raw pet food could be a sentinel for emerging antibiotic resistance,” said Cline.

Another study analyzing 35 frozen RMBDs for cats and dogs found the presence of the following zoonotic pathogens, by percentage of affected products⁶:

1. Escherichia coli serotype O157:H7: 23%
2. extended-spectrum beta-lactamases-producing E. coli: 80%
3. Listeria monocytogenes 54%
4. other Listeria species: 43%
5. Salmonella species: 20%
6. Sarcocystis cruzi: 11% p
7. S tenella: 11%
8. Toxoplasma gondii: 6%

Cline advises that in addition to evaluating RMBDs for nutritional adequacy, they should also inform pet owners of these possible risks. The potential vectors for pathogen exposure include food utensils and bowls, litter boxes, feces, the diet itself, and cats with bacteria present in their mouths or on their coats. The elderly, young, pregnant, lactating, and immunocompromised are at particular risk, she said.

References

1. Dodd S, Cave N, Abood S, Shoveller AK, Adolphe J, Verbrugghe A. An observational study of pet feeding practices and how these have changed between 2008 and 2018. Vet Rec. 2020;186(19):643. doi:10.1136/vr.105828
2. Cline, MG. Unconventional diets…for cats! Presented at: Atlantic Coast Veterinary Conference; October 10-12, 2022: Atlantic City, New Jersey. www.dvm360.com/2022-acvc-proceedings
3. Kanakubo K, Fascetti AJ, Larsen JA. Assessment of protein and amino acid concentrations and labeling adequacy of commercial vegetarian diets formulated for dogs and cats. J Am Vet Med Assoc. 2015;247(4):385-392. doi:10.2460/javma.247.4.385
4. Wilson SA, Villaverde C, Fascetti AJ, Larsen JA. Evaluation of the nutritional adequacy of recipes for home-prepared maintenance diets for cats. J Am Vet Med Assoc. 2019;254(10):1172-1179. doi:10.2460/javma.254.10.1172
5. Freitas AR, Finisterra L, Tedim AP, et al. Linezolid- and Multidrug-Resistant Enterococci in Raw Commercial Dog Food, Europe, 2019-2020. Emerg Infect Dis. 2021;27(8):2221-2224. doi:10.3201/eid2708.204933
6. van Bree FPJ, Bokken GCAM, Mineur R, et al. Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Vet Rec. 2018;182(2):50. doi:10.1136/vr.104535