The importance of dietary protein for dogs 

When it comes to feeding our dogs, the options can be overwhelming – wet, dry, grain-free, hypoallergenic… the list goes on. Amongst all the nutrients dogs require, protein is one of the most essential. Whether you’re raising a growing puppy, caring for an active adult, or supporting a senior furry friend, understanding the role of dietary protein can help you make informed choices about your dog’s food and ultimately long-term health. 

What is protein? 

Proteins are large, complex molecules made up of smaller units (amino acids), which serve as the building blocks of the body. Together, they are used to build and repair cells and muscle, as well as forming essential structures such as enzymes, hormones and antibodies. Protein can also act as a source of energy, especially in diets where carbohydrate levels are low. 

There are two basic types of amino acid: essential and nonessential. Essential amino acids cannot be synthesised by the body, therefore need to be supplied to the body via diet. These amino acids are crucial for maintaining muscle mass, skin health, coat condition, and internal organ function. 

In dogs, there are ten essential amino acids:  

In comparison, non-essential amino acids can be made by the body, typically by chemical transformations of one or more essential ones, therefore do not need to be supplied by diet alone. 

Function of protein 

After ingestion, proteins are broken down into their amino acids by enzymes in the stomach and small intestine. These amino acids are then absorbed into the bloodstream and used towards: 

1. Muscle function 

Muscle tissue is made primarily by protein. During growth stages, such as puppyhood, dogs require a high protein diet to build strong muscles. In adult dogs, protein also helps maintain muscle mass, especially in active or working breeds. In senior dogs, adequate protein can slow age related muscle loss and help maintain mobility and strength. 

2.  Tissue repair 

Dogs that are recovering from surgery, illness, or injury can have increased protein requirements. Protein helps repair damaged tissues, build new cells, and support a faster, more effective recovery. Note, there are certain diseases and conditions where protein needs to be limited so make sure you speak to your vet about your dog’s specific dietary needs. 

3. Promoting healthy skin and coat 

A shiny coat and healthy skin are often signs of good nutrition. Protein plays a key role in the production of keratin, a structural protein that makes up hair and skin. Deficiencies in dietary protein can result in dry skin, brittle fur, hair loss, or skin infections. 

4. Supporting the immune system 

As discussed above, antibodies, enzymes, and many hormones are made from proteins. A well-balanced diet with sufficient protein helps maintain immune function, allowing your dog’s body to fight off infections more effectively. 

5. +/- Energy source 

Although carbohydrates and fats are primary energy sources, protein can also be used.  

Sources of dietary protein 

Not all protein sources are created equal. The quality of protein in a dog’s diet matters just as much as the quantity. High quality proteins are those that are easily digestible and contain all essential amino acids in the correct proportions. Most sources do not contain all the essential amino acids in the correct proportions, therefore multiple sources should be included to create a well-balanced diet. 

Sources of protein include both animal and plant origin: 

Animal based protein include: 

Plant based proteins include: 

It should also be highlighted here, that dogs usually require a mixture of plant and animal-based proteins to be healthy; a diet solely based around plant protein is often inadequate as they tend to be deficient in one or more essential (for dogs!) amino acids, or contain anti-nutrients that prevent dog’s form absorbing and/or using the amino acids present. This seems to be a particular problem with legume-based proteins, for example. 

How much protein do dogs need? 

The protein needs of a dog vary based on life stage, activity level and health status. Generally, puppies will need more protein than adults, which is in turn more than the requirement for seniors. However, as alluded to above, health status and specific health conditions can massively impact individual requirements, so it is incredibly important to check with your vet regarding individualised care. 

When it comes to feeding your dog, irrespective of the specific nutrient in consideration, balance is crucial. While protein is essential for nearly every bodily function, both deficiency and excess can be incredibly problematic for your pet. Thankfully, both are relatively rare when dogs are fed a complete and balanced commercial diet. 

Protein deficiency: signs and risks 

Protein deficiency can occur in dogs fed homemade diets. A diet too low in protein can lead to serious health problems, and when severe can be fatal in growing puppies. Some signs of protein deficiency include: 

The danger of homemade diets. 

Some owners choose to prepare homemade diets for their dogs. While these can be done safely, they come with risk – particularly when considering and meeting precise protein and amino acid requirements. 

Although it depends on the protein, generally no one source will provide a complete amino acid profile, therefore homemade diets need to be specially formulated to ensure all essential amino acids are provided. It is strongly recommended that if you are seriously considering a homemade diet for your dog, to consult a veterinary professional to ensure they meet your dog’s protein and micronutrient needs. Both vets and veterinary nurses are trained and experienced to provide advice, but for more complex situations, you may need to consult a board-certified Veterinary Nutritionist. 

Diseases causing protein deficiency 

As all FEDIAF-compliant or UK Pet Food commercially formulated diets should provide adequate protein, deficiency caused by diet is relatively uncommon. Protein deficiency potentially occurs more commonly when a dog is suffering a chronic disease causing either a problem in protein absorption and/or causing protein to be lost via the urine or stools. Such diseases can lead to a protein losing enteropathy (i.e. there is a problem with protein absorption in the gut) or a protein losing nephropathy (i.e. there is a problem with losing protein from the body in urine). 

Protein Losing Enteropathy (PLE) 

Protein losing enteropathy refers to a group of gastrointestinal conditions where protein is not correctly absorbed from the gut. So when you pet eats protein in their food, the body cannot use it for the essential functions as discussed above. Instead, it is lost via the stools, often as diarrhoea. There are several conditions which come under this heading, such as: 

The signs of these diseases will vary, but generally will not present the same as a dog with ‘simple’ dietary protein deficiency. These individuals will have other signs in addition, such as:  

With these conditions, your pet will likely be quite poorly so efficient diagnosis and treatment is vital. Treatment often focusses on the underlying cause of the protein deficiency.  

Conclusion 

Protein is one of the most essential nutrients and in many regards, is the cornerstone of canine health. From growth and muscle maintenance to immune support and wound healing, protein affects nearly every aspect of your dog’s physical health. 

When considering protein content in your dog’s diet, it is important to focus on protein quality, specifically the amount of essential amino acids provided, as well as considering the specific life stage and health of your pet, as both can hugely affect protein demand.   

As always, if you’re unsure whether your dog’s current diet meets their protein requirements – or if you are considering a diet change or switching to homemade – it is essential to speak with a veterinary professional. Both vets and vet nurses are qualified to speak to you about your pet’s diet and individual needs, and often specific diet plans can be formulated.  

Further Reading 

Dog Nutrition Basics – Purina 

Too much protein in dog food? – Hills  

The Protein Paradigm – Today’s Veterinary Practice 

Small Animal Clinical Nutrition – Chapter 5, Macronutrients