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Hydrolyzed protein in dog food consists of protein that that has been broken down into smaller components. Sounds complicated?

Let's face it: nowadays, there are more and more types of diets for dogs on the market, and things get get easily confusing and overwhelming, especially when you stumble on terms that are not easy to understand.

One of them is hydrolyzed protein. 

You may have heard a veterinarian recommend a diet with hydrolyzed protein for your dog or you may have stumbled on this term being advertised in pet food stores, but what exactly is hydrolyzed protein and how can it benefit your dog? Let's discover more.


A Word About Protein

In order to understand how hydrolyzed protein works, it's first important understanding the role of protein in dog food.

 Protein consists of large molecules of amino acids, the building blocks that make up proteins.

 Amino acids play an important role in the correct functioning of cells, muscles and tissue. 

Amino acids also play a role in the correct functioning of a dog's organs, glands, tendons and arteries and help in repairing tissue and removing waste from the body.

So to re-cap, protein is made of large, complex molecules which are made up of hundreds of smaller individual units known as amino acids. 

Did you know? "There are twenty-two amino acids used by the body to build proteins involved in many important functions...Among the amino acids used within the body, there are ten amino acids that are essential in the diet for dogs," explains Sally Perea, veterinary nutritionist.

The Hydrolysis Process


The word hydrolysis comes from the Greek word "lysis" which means splitting and the word "hydro" which means water.

 Basically, when protein is hydrolyzed it's broken down into smaller parts. 

The word "hydro" is used because the breaking down of components often takes place by the addition of a molecule of water.

The protein is therefore split into smaller molecules such as amino acid chains (polypeptide chains) and free amino acids.

These smaller individual amino acid components make them unlikely to trigger an allergic reaction, hence why dog foods with hydrolyzed proteins are often considered to potentially be "hypoallergenic."

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What happens exactly is that, since the proteins are broken up, the dog's immune system is somewhat "tricked," as it no longer recognizes the proteins they were originally and therefore, no longer reacts. This method has been used for years when it comes to infant formula so to help infants having a hard time tolerating cow milk.

Did you know? Most food allergens consist of glycoproteins ranging in size from 18 kD to 70 kD (kilodalton.) Hydrolysis reduces the proteins to small polypeptides creating proteins below this size that are therefore "hypo-allergenic."

Pros and Cons

Hydrolyzed protein diets are not only good for dogs suffering from allergies.

 Since they are highly digestible, they may also benefit dogs suffering from inflammatory bowel disease (IBD), exocrine pancreatic insufficiency, portosystemic shunts and hepatic encephalopathy, explains veterinary nutritionist Dr. Dottie LaFlamme in an article for Clinician's Brief.

Also, hydrolyzed diets may be beneficial as well to Dalmatians, a breed particularly prone to bladder stones, but without having to excessively restrict the protein content in their food.

Among the downfalls of hydrolyzed proteins is the fact that, since the protein sources are broken down, the food might not be as palatable as it would be with the protein kept in its original form.

Other potential problems involve reduced nutritional value, hypoosmotic diarrhea and persistent allergies, according to Muller and Kirk's Small Animal Dermatology. 

Another disadvantage is that people feeding such diets, must adhere to a very strict feeding regimen, not allowing anything else other than the diet and water.

Warning: While hydrolyzed protein diets have a lower incidence of causing allergens, none of the currently available diets are hydrolyzed to such an extent to be able to guarantee complete absence of any allergens. It's therefore best to use caution and select a diet that is free of the protein that the patient is known to be sensitized to, suggests veterinary nutritionist Nick Cave.

Dog Foods With Hydrolyzed Protein

dog eating

Today, the use of hydrolyzed protein is a fairly new concept and more brands of dog foods are offering this option for dogs suffering from food allergies and digestive problems.

Dog food brands currently known for using hydrolyzed protein include Hill’s Prescription Diet z/d Ultra Canine, Purina HA Hypo Allergenic Canine Formula, Royal Canin Veterinary Diet Canine Hypoallergenic.

Most of these diets use soy and chicken as protein sources. 

Soy is often chosen because few dogs have been exposed to soy based diets so they're less likely to have been sensitized to it, explains veterinarian Matthew J. Ryan with the Veterinary Hospital University of Pennsylvania Clinical Dermatology & Allergy Service.

Did you know? Hydrolyzed protein diets are different from novel protein diets. While a novel protein diet offers a source of protein the dog was never exposed to before (like exotic meats such as duck, bison and venison), hydrolyzed protein diets expose to less exotic proteins that are simply broken down in smaller components.


  • DVM360, When pieces are better than the whole: Hydrolyzed protein diets (Sponsored by Nestlé Purina), by Dottie LaFlamme, retrieved from the web on Oct 11, 2016.
  • HYDROLYSED PROTEIN DIETS Nick Cave, BVSc, MVSc, MSCVSc, DACVN Massey University, Palmerston North, New Zealand, retrieved from the web on Oct 11, 2016
  • University of Pennsylvania Clinical Dermatology & Allergy Service, What to Feed? Hydrolyzed Diet vs. Novel-Protein Diet, retrieved from the web on Oct 11, 2016

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