Shun NagaiMany people know that high-quality protein is essential for a dog’s body and overall health. However, protein comes in many different forms, and not everyone knows which type of protein is actually best for dogs.
Even when comparing the many dog foods currently available on the market, it is not always easy to determine which protein source is the most suitable. High-protein dog food is often seen as the best option, but that is not necessarily true.
The Relationship Between Protein and Digestion
Protein is not only a source of energy for dogs, but also a source of essential amino acids. Dogs cannot grow properly or maintain good health without these essential amino acids.
To explain a little further, dogs require 20 amino acids in total. Of these, 10 can be produced within the body, while the remaining 10 must be obtained from the protein in their diet.
However, in order to make use of these amino acids, dogs first have to digest the protein they consume. This means that even if a dog food is high in protein, it will not provide sufficient essential amino acids if the dog cannot digest that protein properly.
One study found that dogs can actually absorb more amino acids from a food containing less protein if that protein is easier to digest, compared with a high-protein food that is harder to digest. In other words, it is important to choose ingredients with good digestibility, not just high protein content.
Easily Digestible Protein Sources
Protein quality is often evaluated using a measure called Biological Value (BV). Biological value indicates how efficiently the essential amino acids from food are absorbed and utilized by the body, making it a useful indicator of both protein quality and digestibility.
| Rank | Protein Source | Biological Value / Digestibility | Notes |
|---|---|---|---|
| 1 | Whole egg | 100% | Considered a complete protein source |
| 2 | Lamb, chicken, beef | 92% | Organ meats such as liver and kidney are around 90% |
| 3 | Fish | 75% | Also provides omega fatty acids |
| 4 | Plant proteins | 54%–75% | Includes corn, soy, and legume/grain meals |
1. Whole Egg
Whole egg is often described as a complete food and is considered a perfect protein, with a biological value of 100%. Egg whites are rich in amino acids and are easy to digest, while egg yolks provide a good source of B vitamins. Dogs can be fed whole eggs, and in some cases the shell may also be included as a calcium source.
That said, eggs alone cannot meet all of a dog’s nutritional requirements. In addition, feeding more than one egg per day is generally not recommended.
2. Lamb, Chicken, and Beef
Lamb, chicken, and beef come next, with a biological value of 92%. Organ meats such as liver and kidney have a biological value of around 90%.
Among the various animal protein sources, lamb and chicken are considered especially easy for dogs to digest, followed by beef.
One major reason these protein sources are so commonly used in premium dog foods is that they are more digestible than many other protein options.
Beef and Pork for Therapeutic Diets
Beef and pork contain the lowest levels of sodium. Pork contains the highest level of potassium, while chicken contains the lowest. This information can be important when developing pet food for animals with heart or kidney disease.
For dogs with certain heart conditions, meats that are lower in sodium may be more appropriate. For dogs with certain kidney conditions, meats lower in potassium may be preferred.
3. Fish
Fish is an excellent source of protein and also contains omega fatty acids, although its digestibility is approximately 75%.
Fish is still a highly valuable protein source for dogs and compares favorably with beef. In fact, fish has a slightly higher protein ratio than beef by around 3%. However, beef is generally easier to digest than fish.
Fish is also lower in fat than beef and contains omega-3 and omega-6 fatty acids, making it one of the ideal protein sources for dogs that need to lose weight.
4. Plant Proteins
Plant-based protein sources such as corn, soy, and legume or grain meals are also relatively digestible, but they do not provide as wide a range of amino acids.
However, because dogs are omnivorous, some studies suggest that including grains and other carbohydrate-containing ingredients in the diet may actually support better health.
Compared with animal proteins, plant proteins are generally less digestible, with digestibility ranging from 54% to 75%.
That said, according to an article published by the Journal of the American Veterinary Medical Association (JAVMA), research has shown that properly processed soy-based protein can have digestibility comparable to animal protein sources.
Reducing Risk with Limited-Ingredient Diets
Many dogs may experience digestive upset with certain protein sources, so using a single-protein dog food can be one way to improve digestive issues.
A single-protein formula can also help identify which protein source may be causing the digestive problem in the first place.
Ingredients Rich in Protein
Amino acids are the building blocks of protein. When animals consume protein, it is broken down into amino acids. These amino acids are then used to build new proteins in the body or to provide energy.
However, not all protein sources are broken down into the same quality or quantity of amino acids. The highest-quality proteins are those that are rich in essential amino acids and easy for pets to digest.
Protein-rich ingredients include fish, lamb, chicken, beef, and pork. Fish has the highest protein ratio at 29.91%, while the other meats contain around 26 grams of protein per 100 grams (26.0%). Beef is considered especially suitable for growing dogs.
Pork is also an excellent protein choice for growing dogs. It contains a similar amount of protein to beef and chicken, while also providing a higher level of high-quality animal fat needed for growth.
| Ingredient | Protein Content |
|---|---|
| Fish | 29.91% |
| Lamb | Approx. 26.0% per 100 g |
| Chicken | Approx. 26.0% per 100 g |
| Beef | Approx. 26.0% per 100 g |
| Pork | Approx. 26.0% per 100 g |
Protein Sources That Require Caution
Chicken is commonly used as a main ingredient in commercial dog food. This is because it not only provides high-quality protein, but also contains omega-6 fatty acids.
However, despite being one of the most widely used ingredients in dog food, chicken is also frequently listed as one of the top ingredients associated with food allergies in dogs.
These allergies are often misdiagnosed or overlooked, but they are often the underlying cause of skin and digestive problems.