Why Hydrolyzed Pet Food Isn't the Answer for Sensitive Pets

Analysis by Dr. Karen Shaw Becker

hydrolyzed pet food

Story at-a-glance -

  • Formulas containing hydrolyzed proteins are one of the “answers” the processed pet food industry has come up with to meet consumer demand for better quality food for animal companions
  • Hydrolyzed proteins are intact proteins that have been chemically pulverized into smaller pieces to avoid stimulating the immune system of pets with GI issues
  • Recent research suggests that hydrolyzed protein diets are no more beneficial than intact protein diets; food sensitivities in dogs and cats may be the result of an abundance of foreign contaminants found in most ultraprocessed pet foods
  • Pets with suspected food intolerances should be tested to determine the specific food(s) they react to; once the problem food(s) have been identified, a 2-to-3-month novel diet should be introduced

According to a company (BRF Ingredients) that supplies chicken protein hydrolysate (hydrolyzed chicken) to ultraprocessed pet food manufacturers, "The consumer market has been showing increasing interest in purchasing quality products that can guarantee the health and well-being of their pets."1

This is a true statement, but what isn't mentioned is the fact that increasingly, consumers are becoming concerned that the highly refined commercial dry and canned diets they've been feeding their pets for several decades aren't ideal. The same pet food industry that produces those diets is attempting to answer consumer concerns by "reimagining" those diets, creating versions of them designed to cause fewer digestive and other problems for sensitive pets.

In other words, ultraprocessed pet food producers are looking for ways to climb out of the hole they've dug for themselves, and hydrolyzed proteins is one of those ways.

How Animal Protein Goes From Intact to Hydrolyzed

The hydrolyzation process was invented and patented nearly 25 years ago. According to a filing at FreePatentsOnline.com, preparing hydrolyzed food product (in this case chicken) for animal consumption involves the following process:2

"A food product for animal consumption is prepared from an animal by-product, preferably a complete avian carcass. A heated hydrolyzing agent is applied by spray or dip coating to the carcass exterior. After initiation of hydrolysis, the carcass is ground, enhanced by additives, then steam heated to a temperature of about 200 degrees F.

The heated by-product is provided as a slurry or as dry particulates to a twin-screw extruder.

As it is transported across several zones of the extruder, the by-product is thoroughly dispersively mixed and subjected to high pressures and temperatures, vented to release moisture, neutralized with a neutralizing agent, and blended under high temperatures and pressures sufficient to completely sterilize what has become a highly uniform and homogeneous by-product mass.

The by-product mass is extruded and cut into pellets, which then are dried to a moisture content at or below 10 percent."

In a nutshell, hydrolyzed proteins are intact proteins that have been chemically pulverized into smaller pieces to theoretically avoid stimulating the immune system of pets with "sensitive stomachs."

Why Hydrolyzed Proteins Became a Thing

Pet food manufacturers introduced hydrolyzed protein formulas to the marketplace by suggesting that intact proteins are the culprit causing the epidemic of diet-related health conditions in pets. Hydrolyzed protein formulas are marketed as hypoallergenic diets for pets with food sensitivities. Additional marketing claims for these foods are that they are palatable and easy to digest and feature high amino acid and protein content.

In my experience, pets fed unrefined high quality, human-grade protein from a variety of animal sources do not typically develop sensitivities to quality unadulterated proteins. It is when the same low-quality, ultraprocessed protein is fed day in and day out for months or years that leaky gut occurs and paves the way for an intolerance to a specific protein.

Many pet parents find an inexpensive ultraprocessed pet food their dog or cat really seems to like, and they feed it exclusively for long periods of time. Eventually, many of these pets develop sensitivities to certain ingredients, often the low-grade source of protein included in the formula.

In my opinion, the problem isn't intact animal protein. The problem is factory-farmed, poor quality, rendered animal protein that has been extruded and high heat processed. While no published research exists to explain why carnivores develop sensitivities to protein, I and many of my integrative veterinarian colleagues suspect foreign contaminants and food processing byproducts may be the reason.

The growth hormones and antibiotics fed to factory-farmed food animals, glyphosate residues, along with the chemical residues and MRPs (Maillard reaction products) that result from high heat processing may actually be the triggers for food sensitivities, not protein itself.

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Research Suggests Hydrolyzed Proteins Aren't the Answer

Recently, I wrote about a current Cornell University College of Veterinary Medicine (CVM) study that is evaluating the effectiveness of dietary changes in treating persistent gastrointestinal (GI) problems (aka chronic enteropathy) in dogs.

Conventional veterinar­ians who include dietary changes in their treatment plans for GI patients are increasingly prescribing hydrolyzed protein formulas. But according to the lead author of the Cornell study, "… no one really knows why or how these diets work or why the original diet caused clinical signs."3

The dogs participating in the study are separated into three groups, two of which receive hydrolyzed protein diets, with the remaining control group eating a "high-quality maintenance mixed-protein diet." All three diets contain the same balance of carbohydrates, protein and fat.

According to the researchers, the results of the study so far are encouraging and even "dramatic" for many of the dogs. Simpson and his colleagues, while pleased with their preliminary study results, are also somewhat surprised because they expected the dogs on the hydrolyzed diets to do much better than the dogs fed regular maintenance diets.

"Conventional wisdom would suggest that the hydrolyzed diets would do better and dogs on the intact mixed-protein maintenance diets would fail to respond," he explains. "Yet, at three months, almost all dogs, independent of group, have had positive responses, which means the placebo group is performing equally well."4

Simpson's hypothesis:

"… while we are still in the dark about what's driving adverse reactions to food in dogs, the positive responses to a high-quality, intact mixed-protein-source diet suggest they are not a simple allergic response to intact protein. Perhaps non-protein ingredients or additives may be causing adverse reactions."

I agree with Simpson's theory that today's epidemic of GI issues in dogs (and cats) isn't as simple as an allergic response to intact proteins; however, I do think factory-farmed meats may present a problem for pets, especially because antibiotic residues are passed up the food chain.

Grains present in many pet foods are commonly genetically modified and often harbor glyphosate residues that cause dysbiosis and leaky gut, not to mention mycotoxins (responsible for killing 28 dogs in December alone that were eating contaminated kibble).5 Adding fuel to the fire, pet foods made with legumes contain anti-nutrients that can create GI inflammation.

And I definitely feel that all the "non-protein ingredients" and other additives (e.g., flavor enhancers, emulsifiers and dyes) found in ultraprocessed diets are a foundational problem, along with the changes that occur to ingredients subjected to high heat processing, including the formation of Maillard reaction products (MRPs) as well as advanced glycation end products (AGEs) that create gut inflammation in animals.6

A Better Approach

The first thing I recommend for animals over the age of 12 months who I suspect are dealing with a food sensitivity is a NutriScan test. It's also very important that pet parents work with an integrative veterinarian to identify root causes and contributing triggers and develop a customized healing protocol.

The NutriScan panel tests for 24 purified food extracts that recognize 56 food ingredients, and the results can often identify the specific ingredient(s) in your pet's food that are causing a problem, which makes it much easier to customize a diet to resolve the issue.

After determining your pet's food sensitivities with a NutriScan test, my recommendation is to introduce a novel diet to promote healing. This means transitioning her to a different food she isn't sensitive to containing ingredients her body isn't familiar with.

Unfortunately, many pet foods claiming to contain "novel proteins," don't. In addition, pet food mislabeling is a widespread problem, so if you're planning to go with a commercially available processed novel diet, be aware it will undoubtedly contain ingredients you're trying to avoid.

The safest approach, at least for the first few months, is homecooked meals that allow you to control virtually everything that goes into your animal companion's mouth. Second best is a human grade commercially available fresh food containing an uncommon protein, produced by a company you trust.

It's very important that all suspect foods be avoided for at least several months. Oftentimes animals experience a reaction to both the primary protein and carbohydrate sources in their diet. In addition to avoiding all potentially problematic foods, it's important to reduce or eliminate any "filler ingredients" (as well as synthetic nutrients) that can play a role in food sensitivities and inflammatory conditions.

I also believe pets with food intolerances do best on a very low-starch diet. Starches (aka soluble carbohydrates) are pro-inflammatory to the body and can exacerbate GI inflammation. Microbiome expert Dr. Holly Gantz has also seen beneficial changes in pets' microbiomes when excessive carbs are reduced.

Until new labeling standards are fully in effect, pet food manufacturers aren't required to list carbohydrate content on their labels, so you have to calculate it yourself. It's worth taking the time to do this before choosing a novel diet (less than 20% carb content is the goal).

Returning Your Pet to a Regular Diet

A dog with food sensitivities should remain on a novel diet for a minimum of 2 months and preferably 3, to allow the body time to clear out the allergenic substances and begin the detoxification process.

During this 3-month period I also typically address dysbiosis with the appropriate probiotics, microbiome restorative therapy and nutraceuticals. If your pet has had multiple rounds of antibiotics, assessing the microbiome and beginning microbiome restorative therapy can be life changing. This is where partnering with a integrative veterinarian that has experience in healing dysbiosis is important.

Once your pet has completed 2 to 3 months on a novel diet, other foods can be slowly reintroduced one at a time while his response is closely monitored. Some pets show dramatic improvement on the new diet, and in those cases, I often don't rush the reintroduction of food that could be problematic.

When your pet is stable and doing well, my recommendation is to find at least 1 and preferably 2 other protein sources he tolerates well so that every 3 to 6 months, you can rotate proteins and hopefully avoid further intolerances.

In addition, I believe the "cleaner" the proteins, the less chance your pet will become sensitive to them over time. Clean animal proteins are less reactive because there are no chemical residues to contend with. For example, food animals raised on a natural diet (grass-fed, not factory farmed), as well as hormone-free animals, are better food sources for sensitive pets.