Hydrolyzed Protein Pet Food…Um, No.

Hydrolyzed protein pet food is prescribed by veterinarians for companion dogs or cats that have been diagnosed with a sensitivity (allergy) that is expressed through the skin, or diagnosed with inflammatory bowel disease or food intolerance.

The hydrolyzation process is stated to chemically break down a protein to the point that it no longer causes an “allergic” reaction in a dog or cat that is in fact sensitive or intolerant to said protein. 

Numerous studies have been conducted that either dismiss or confirm the reduction or elimination of symptoms after companion dogs or cats were fed a hydrolyzed pet food. 

BUT…Many of the studies that confirm reduction or elimination of symptoms still have caveats. 

Case in point:

  • A 2016 study completed by Petra Bizikova and Thierry Olivry concluded that between 20 to 50 percent of dogs eating a hydrolyzed protein will still experience flare-ups of symptoms.
  • A 2017 study by Kathrani et al. involving cats found that some cats will still have similar reactions to a whole protein eating a hydrolyzed diet.
  • Sensitivity studies conducted before 2014 often used a scale called Canine Atopic Dermatitis Extent and Severity Index 2 or 3 (CADESI), which basically provides a guide to gauging a companion dog’s skin reactions via observation. While the standardization across veterinary medicine is wonderful, CADESI-3 was complicated and cumbersome. CADESI-4 is the next evolution of the index and is now considered to be the standard. 
  • These studies were typically funded by hydrolyzed pet food manufacturers or the researchers had ties to the manufacturers.

Let’s look at what Nicholas Cave has to say about protein hydrolyzation:

“Any reduction in antigenicity or clinical reactivity at which point a diet could be considered ‘hypoallergenic’ is arbitrary, however, unless it is absolute.”

In our opinion, his statement means a complete elimination of the offending protein from a companion dog or cat’s diet. We agree with that, as it is illogical to feed an offending protein in any form because it will more than likely continue to cause adverse events – whether observable or not – in any dog or cat that is diagnosed with a food sensitivity or intolerance. 

What more can we say about it? Food ingredient manipulation is illogical when the simplest solution – elimination of offending ingredients – is the best solution.

When W. Jean Dodds advises clients after they receive their pet’s NutriScan results, she tells them to eliminate everything associated with the offending protein. For instance, a companion pet parent whose dog is sensitive to chicken will have to eliminate not only the chicken meat, but also chicken fat, chicken broth, chicken bone, etc. 

Hydrolyzed Diet Profiles

The majority of hydrolyzed diets are made with hydrolyzed chicken, soy or salmon. After reviewing hydrolyzed diet ingredients, these diets also included ingredients such as beet pulp, cornstarch, brewers rice, pea fiber, fish oil, chicken fat or potatoes. 

  • Soy carries its own set of issues from affecting the thyroid to being genetically modified. 
  • A 2016 study demonstrated that dietary beet pulp may decrease taurine status in dogs fed low protein diets. 
  • …And the rest of the ingredients: what if a dog or cat has reactions to any of the other ingredients such as rice, peas, fish oil, corn or potatoes? Continuous feeding of these potentially offending ingredients – or any of the offending ingredients – will continue to cause either observable or underlying chronic food-related reactions in companion pets. 

Bottom Line…Soy and chicken are definitely not novel proteins in pet food diets. So, choose a novel protein for your companion pet based on NutriScan results. The best solution is to cook for your pet. Of course, home cooked meals should be nutritionally balanced, have the proper ratio of calcium to phosphorus, and include vitamin D supplementation along with other essential vitamins and minerals. 


Ambrosini, Yoko M et al. “Treatment With Hydrolyzed Diet Supplemented With Prebiotics and Glycosaminoglycans Alters Lipid Metabolism in Canine Inflammatory Bowel Disease.” Frontiers in veterinary science vol. 7 451. 30 Jul. 2020, doi:10.3389/fvets.2020.00451, https://www.frontiersin.org/articles/10.3389/fvets.2020.00451/full

Becker, Karen. “Research Suggests Hydrolyzed Proteins Aren’t the Answer.” Healthy Pets, Mercola.com, 17 Jan. 2021, https://healthypets.mercola.com/sites/healthypets/archive/2021/01/17/hydrolyzed-pet-food.aspx

Bensignor, Emmanuel et al. “Efficacy of an essential fatty acid-enriched diet in managing canine atopic dermatitis: a randomized, single-blinded, cross-over study.” Veterinary dermatology vol. 19,3 (2008): 156-62. doi:10.1111/j.1365-3164.2008.00670.x, https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3164.2008.00670.x

Bizikova, Petra, and Thierry Olivry. “A randomized, double-blinded crossover trial testing the benefit of two hydrolysed poultry-based commercial diets for dogs with spontaneous pruritic chicken allergy.” Veterinary dermatology vol. 27,4 (2016): 289-e70. doi:10.1111/vde.12302, https://onlinelibrary.wiley.com/doi/abs/10.1111/vde.12302

Cave, Nicholas J. “Hydrolyzed protein diets for dogs and cats.” The Veterinary Clinics of North America: Small animal practice vol. 36,6 (2006): 1251-68, vi. doi:10.1016/j.cvsm.2006.08.008, https://www.sciencedirect.com/science/article/abs/pii/S0195561606000994

Glos, Katharina et al. “The efficacy of commercially available veterinary diets recommended for dogs with atopic dermatitis.” Veterinary dermatology vol. 19,5 (2008): 280-7. doi:10.1111/j.1365-3164.2008.00688.x, https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3164.2008.00688.x

Jeromin, Alice. Food Allergy: Fact versus Fiction. Veterinary Practice News, 5 Nov. 2018, https://www.veterinarypracticenews.com/food-allergy-november-2018-2/

Kathrani, Aarti et al. “A descriptive pilot study of cytokine production following stimulation of ex-vivo whole blood with commercial therapeutic feline hydrolyzed diets in individual healthy immunotolerant cats.” BMC veterinary research vol. 13,1 297. 6 Oct. 2017, doi:10.1186/s12917-017-1219-9, https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-017-1219-9

Mandigers, Paul J J et al. “Efficacy of a commercial hydrolysate diet in eight cats suffering from inflammatory bowel disease or adverse reaction to food.” Tijdschrift voor diergeneeskunde vol. 135,18 (2010): 668-72, https://pubmed.ncbi.nlm.nih.gov/20939411/

Marks, Stanley L et al. “Dietary trial using a commercial hypoallergenic diet containing hydrolyzed protein for dogs with inflammatory bowel disease.” Veterinary therapeutics: research in applied veterinary medicine vol. 3,2 (2002): 109-18, https://pubmed.ncbi.nlm.nih.gov/19750741/

Olivry, Thierry et al. “Validation of the Canine Atopic Dermatitis Extent and Severity Index (CADESI)-4, a simplified severity scale for assessing skin lesions of atopic dermatitis in dogs.” Veterinary dermatology vol. 25,2 (2014): 77-85, e25. doi:10.1111/vde.12107, https://docksci.com/validation-of-the-canine-atopic-dermatitis-extent-and-severity-index-cadesi-4-a-_5b06b280d64ab25b6acc0dba.html

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