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Why Pea Protein in Dog Food Isn’t the Best Protein Sources

Pea protein has emerged as a popular plant-based protein in the production of dog food kibble. Derived from peas, it is widely recognized for its high digestibility and superior quality. As a result, many manufacturers have chosen pea protein as their preferred option for incorporating highly nutritious and easily digestible protein into their products.

This guide is part of our series on dog food ingredients and nutrition.

What is pea protein in dog food?

Pea protein is a type of plant-based protein that is derived from yellow peas. It is considered to be a complete protein, meaning it contains all nine essential amino acids that are necessary for dogs to maintain optimal health. This makes it an excellent alternative to animal-based proteins such as chicken, beef, and fish.

How is pea protein made?

The process of obtaining pea protein isolate involves several distinct steps.

  1. First, the yellow peas are milled to break them down.
  2. Next, the proteins are dissolved in water, alkali, or acid to make them soluble. Centrifugation is then used to separate any insoluble components.
  3. After that, the soluble proteins are precipitated at their isoelectric pH and collected either through centrifugation or sieving.
  4. Finally, the collected proteins can be dried as they are or neutralized before drying.

Essentially, pea protein is the resulting component after starch is removed from pea seeds. The process is similar to how soy protein isolate is made but with peas instead of soybeans.

Nutritional Composition of Pea Protein in Dog Food:

Pea protein concentrates, commonly found in powder form and added to dog food formulations, consist of the following nutrients:

Name of NutrientAmount in Grams% Composition
Protein1580.1%
Carbs15.3%
Fiber15.3%
Fat1.58%
Sodium0.231.2%
Iron0.0050.0%
Total18.735100%

Name of Nutrient Amoung in Grams Nutrient % Protein 15 80.1% Carbs 1 5.3% Fiber 1 5.3% Fat 1.5 8.0% Sodium 0.23 1.2% Iron 0.005 0.0% Total 18.735 100.0%

Pea protein contains 80.1% protein and this is why it is preferred by manufacturers as a protein source in dog food formulations. Out of 3662 dog food brands available on Chewy, 369 of them have pea protein as the main protein source with most brands having it among its top 5 ingredients.

Manufacturers also prefer pea protein because it contains all nine essential amino acids that dogs need. However, it is relatively low in methionine and tryptophan. To compensate for this, you can include other methionine-rich foods such as eggs, fish, poultry, beef, pork, or brown rice in your dog’s diet.

Drawbacks of Pea Protein in Dog Food Diets:

Low Biological Value:

Pea protein has a relatively low biological value of 65 when compared to other plant-based protein sources like soybean protein isolate, which has a value of 74, and canola protein isolate, which has a value of 80. Biological value measures how effectively a dietary protein can be utilized to build the body’s own protein. It specifically quantifies the grams of body protein that can be formed from 100g of dietary protein. The higher the biological value, the more efficiently the protein is utilized by the body.

Other studies have found One 30 g pea protein powder provides about 20 g of incomplete protein. The total value is less than what’s needed for an adult meal, let alone nutritionally sufficient dog food meals.

Unlike other protein sources like eggs, whey, and soy, which are considered complete proteins, pea protein is categorized as an incomplete protein. This is due to its lower levels of certain essential amino acids that are vital for the body. Consequently, it cannot provide all the necessary building blocks for your dog’s muscles, organs, and tissues.

Despite low BV, manufacturers prefer it as it boosts the reported protein amount:

Unsurprisingly, pet food manufacturers like to fill their dog foods with low-quality protein sources such as pea protein when possible. It helps them create a cheaper product with higher reported levels of protein. For example, the manufacturing cost of beef protein (BV: 80) is much higher compared to plant-based proteins like pea protein (BV:65). This allows manufacturers to include a smaller amount of high-quality protein sources and bulk up the rest with pea protein, resulting in a product with high reported levels of protein.

However, this does not necessarily mean that your dog is getting all the necessary amino acids from the protein in their food. Incomplete proteins like pea protein may not provide all the essential amino acids your dog needs, leading to potential deficiencies over time.

Pea Protein is High in Purines:

Peas are relatively high in purines, organic compounds found in some foods that can be converted by the body into uric acid. While purines play a crucial role in the body, excess uric acid can lead to health issues such as kidney stones and gout. Dogs with existing health conditions that are sensitive to purines may not fare well with a diet high in pea protein.

Low Digestibility:

Digestibility refers to how easily the food is broken down and absorbed by the body. Studies have shown that pea protein is not as digestible as other protein sources like chicken, fish meal or beef. In fact, it has a lower digestibility score than egg whites, which are considered the gold standard for protein absorption. Its digestibility score is 86% which is still better than the digestibility of other ingredients such as corn meal, wheat meal, wheat gluten and rice. See the digestibility comparison of various food sources here.

Potential Allergen:

As with any ingredient, there is a chance of an allergic reaction when feeding your dog pea protein. While rare, some dogs may have sensitivities to peas, causing skin irritations, digestive issues or other symptoms. If your dog experiences any adverse reactions while on a pea protein-based diet, consult with your veterinarian and consider switching to a different protein source.

High in Anti-Nutrients:

Anti-nutrients are compounds that interfere with nutrient absorption and digestion. Pea protein contains trypsin inhibitors, which block the enzyme trypsin responsible for protein breakdown. These inhibitors may lead to gastrointestinal side effects such as bloating and gas in some dogs. However, this issue can be minimized by proper processing of pea protein through heat treatment or fermentation.

Pea Protein vs Pea Flour:

Pea flour is created through the dry milling process of peas with their hulls removed. Meanwhile, pea protein concentrate is typically produced by employing dry separation methods, whereas pea protein isolate is obtained using wet processing techniques.

Dry separation used to produce pea flour is better because it eliminates the need for wet materials, which are typically more prone to microbial contamination. This makes pea flour a safer option compared to pea protein concentrate or isolate.

However, peas and pea flour have different nutritional profiles. Pea flour contains higher levels of carbohydrates and lower levels of protein compared to pea protein concentrate or isolate due to the removal of hulls. Therefore, if your dog requires a higher protein diet, pea protein concentrate or isolate would be more beneficial.

Pea Protein vs Soybean Protein:

Soybean protein is commonly used in dog food as a plant-based protein source. However, pea protein may offer some advantages over soybean protein. Pea protein is rich in essential amino acids that are vital for the proper growth and maintenance of dogs. Notably, pea protein boasts a higher leucine content compared to soy protein, making it an excellent choice for promoting muscle growth and facilitating recovery. It also has a lower risk of allergenicity compared to soybean protein.

Additionally, soybean protein has been linked to thyroid issues in dogs due to its goitrogenic properties. Pea protein, on the other hand, does not contain these compounds and is therefore a safer choice for dogs with thyroid concerns.

Pea Protein vs Animal-based Protein:

Animal-based proteins, such as chicken or beef, are often praised for their high digestibility and bioavailability. While pea protein has all the essential amino acids, it is considered an incomplete protein as it lacks sufficient levels of methionine and cysteine. However, by combining pea protein with other plant-based proteins that are rich in these amino acids (such as rice or hemp), a complete amino acid profile can be achieved.

Furthermore, animal-based proteins can often trigger allergies in dogs, especially if they have sensitivities to certain types of meat. Pea protein, being a plant-based protein, can also cause allergies but is less likely to cause adverse allergies and can be a suitable alternative for dogs with dietary restrictions.

Bottom line:

We do not like pea protein extract/concentrate in dog food diets as it is an incomplete protein with low biological value compared to other protein sources. We prefer protein sources with complete protein profiles and high digestibility, such as animal-based proteins.