Protein, Protein Everywhere.

UPDATED BLOG POST - September 2023 (See below for a NEW study proving that plant-based foods for dogs meet amino acid requirements)

The truth is, protein is abundant in almost every food, including plants. Although it's biologically incorrect, we've been led to believe that protein is only found in animal-based products. This has convinced us that we, and our furry friends, need a substantial amount of animal protein to stay healthy. But what if this isn't true?

In this blog we've got a lot to unpack when it comes to the topic of protein for dogs. Today, I will share:

• Protein basics

• It's importance for dogs’ health and well-being

• Where protein comes from

• The most beneficial or effective way to obtain protein

• The BIG myth of plant proteins being incomplete or “missing” essential amino acids

I hope you enjoy reading this blog and gain a better understanding of the vital role that protein and plants play in sustaining life for all beings on our planet.

What is protein?

Proteins are essential macronutrients that are found in many food sources, both plant or animal. They are made up of long-chain amino acids which are organic compounds that play various important roles in humans and animals, including building and repairing tissues, producing hormones and enzymes, and supporting immune functions. The properties of a specific protein depends on the shape and arrangement of their amino acids (e.g. muscle or enzyme). 

Want to learn more? Book: Molecular Biology of the Cell - 4th edition.

The importance of Protein for Dogs

Protein is broken down in the dog’s digestive tract into amino acids which are later used to produce the necessary proteins required to support healthy body systems. Amino acids are the building blocks for the body's protein synthesis. Following are some of the vital roles of protein for dogs:

• Maintenance, repair and growth of muscle, hair, skin, nails, bones, and other tissues

• Hormones, neurotransmitters, enzymes production

• Immune system function

• Transporting of oxygen in the blood

• Energy source

Want to learn more? Importance of Amino Acids for Dogs

There are 22 amino acids that dogs require for their bodily functions, and they are divided into two groups: essential and non-essential. Twelve of these are considered non-essential because they can be produced endogenously by dogs. The other 10 (called essential amino acids) cannot be synthesized by their body and must be acquired through a proper diet. For this reason, a dog’s diet must contain an appropriate amount of all the essential amino acids required for optimal health.

Here are the 10 essential amino acids for dogs:

• Arginine

• Histidine

• Isoleucine

• Leucine

• Lysine

• Methionine

• Phenylalanine

• Threonine

• Tryptophan

• Valine

Want to learn more? Amino Acids

Although insufficient protein can lead to health problems, such as weight loss, lack of energy and many other conditions, too much protein can be proportionally detrimental. More research is needed to determine the optimal amount of protein for dogs; however, AAFCO provides guidance on the levels of all essential amino acids when formulating foods for dogs. It is known that excessive protein overloads the kidneys and liver which can lead to damage to these organs over time. For this reason, the proper balance of protein, fats, carbohydrates and fibre in the diet is key!

Want to learn more? The Danger of High Protein for Dogs

Why is it important? It is important to note that adequate intake of protein is essential for maintaining dogs' good health; however, the overconsumption of protein can also have negative effects on their health.

Removing the “Intermediary”

Many believe that the best source of protein is from animal-based foods such as meat, poultry, fish, eggs, and dairy products. But the truth is that all proteins come from plants! Plants are the primary source of protein in the food chain. They produce protein through photosynthesis, which is the process of converting sunlight, water, and carbon dioxide into glucose and oxygen. Proteins are made of amino acids, and plants can produce all the essential amino acids. Yay!

Here's something that we don't think about: all animals, including cows, chickens, fish and humans, get their protein from plants or other animals that have already consumed plants. Cows, for example, eat grass and other plants to obtain protein, and chickens eat seeds, and grains, which are all plant-based sources of protein. Fish also get their protein from the algae and plankton they consume*. Learn more about the benefits of algae and why we included it in the LOVE bowl here.

Did you know that plants are also the primary source of all minerals? Dr. McDougall shared on his blog how all minerals are derived from the earth. They go up into the food chain via plants. The same reason why animal foods contain amino acid is also the reason they contain minerals. Thank you plants!

Want to learn more? Read Full Blog: Plant Foods Provide the Nutritional Building Blocks for Optimum Health and Source: The Game Changers

Why is this important? You can choose to remove the “intermediaries” by choosing plant protein sources for your pooch that can be beneficial not only for your dog’s health, and other animals' livelihood, but also our planet's health.

The Myth of Plant-Based Diets “missing” Amino Acids

A review paper published in November 2019 by authors François Mariotti and Christopher D. Gardner examined the adequacy of protein and amino acids intake of adults consuming vegetarian/vegan diets.

“The claim that certain plant foods are “missing” specific amino acids is demonstrably false. All plant foods contain all 20 amino acids, including the 9 indispensable amino acids.” - Dietary Protein and Amino Acids in Vegetarian Diets—A Review, by François Mariotti and Christopher D. Gardner

The review points out that the amino acid profiles of plant sources differ from animal sources; which misled the overstated question of amino acid deficiency in plant-based diets. It also addresses how it is an erroneous approach to focus on one single protein to determine protein quality. A well-balanced vegan/vegetarian diet consisting of enough calories, and a variety of plant sources including protein-rich foods (such as legumes, nuts and seeds) is sufficient to attain appropriate protein levels in adults.

Want to learn more? Read the full paper here.

In the article, Protein-Combining Myth published on NutritionFacts.org in April 2016, Dr. Michael Greger M.D. also demystifies this misconception:

“All essential amino acids originate from plants (and microbes), and all plant proteins have all essential amino acids. The only truly “incomplete” protein in the food supply is gelatin, which is missing the amino acid tryptophan…. It is true that some plant proteins are relatively low in certain essential amino acids.”

Want to learn more? The Protein-combining myth

We can draw the same analogy for our canine companion. A vegan diet for dogs must be carefully formulated to provide all the necessary nutrients that dogs require. A diet that is nutritionally complete and balanced, according to AAFCO guidelines, ensures adequate amounts of not only protein, and essential amino acids, but also carbohydrates, fats, vitamins and minerals so that our furry friends can flourish.

Why is this important? The terms “complete” and “incomplete” proteins are misleading. All plant foods contain all essential amino acids in different proportions. A nutritionally complete and balanced plant-based diet for dogs must combine high-quality ingredients in the right amounts to meet specific target nutrient profiles and exceed minimum requirements for maintenance of a dog's health.

The more digestible an ingredient is, the better it can be tolerated by the gastrointestinal (GI) tract of dogs with tummy troubles, just like in humans. This is due to growing evidence that an undigested protein may overstimulate GI immune system, potentially causing food intolerance and allergy.

Undigested proteins may also encourage the development of certain types of bacteria that can be detrimental to the dog’s colon and overall health. Vegetable proteins are frequently used in pet diets since there are various evidence that they can benefit animals with illnesses like renal, hepatic, and GI disorders.

Want to learn more? Read here: https://www.veterinary-practice.com/article/the-importance-of-vegetable-protein

A study published in 2018 in the Archives of Veterinary Science looked at the characteristics of 14 plant-based protein sources for use in canine and feline nutrition. The protein sources analyzed were protein concentrates (pea, potato, fava bean, yeast, and soy concentrates), pulses (garbanzo beans, navy beans, black beans, lentils, and peas), and by-products (corn gluten meal, peanut flour, soybean meal, and soy flakes).

The protein concentrates and pulses groups had similar amino acid profile. These protein sources showed high amino acid digestibility. In the by-products group, soy flakes and peanut flour showed the lowest overall digestibility (particularly for lysine). The study attributes the lower digestibility in this group to the possible heat damage of the amino acid lysine during processing. Based on their macronutrient compositions, amino acid profile and digestibility, the study suggests these plant-based proteins are viable protein sources for use in canine and feline diets.

UPDATE: New Study - March 2023 - Vegan, human-grade dog foods meet amino acid requirements

Want to learn more? Read the study summary here: https://revistas.ufpr.br/veterinary/article/view/61253/36073

Another research study published in the Journal of Animal Science in June 2020 analyzed the nutrient composition and protein quality (through amino acid digestibility score) of pulse crops, which included, beans, peas, lentils, and chickpeas. The aim of this study was to provide necessary information for the proper use of these ingredients when formulating pet foods. For all pulses, the digestibility of the essential amino acids, with exception of methionine, was considered very high, with values of 80% to 90% (dry matter basis). The study concluded that, “pulse ingredients have the required nutritional characteristics to be viable protein sources in canine and feline foods. However, the use of complementary protein sources is recommended to counterbalance any potential limiting amino acids in pulse ingredients.”

Want to learn more? Read the study abstract here: https://academic.oup.com/jas/article-abstract/98/6/skaa149/5850332?login=false

UPDATE: New Study - March 2023 - Vegan, human-grade dog foods meet amino acid requirements

Why is it important? The rising popularity of plant protein sources resulting from specific canine health conditions (i.e., skin allergies and GI issues), and sustainability concerns has driven growing research studies to determine the macronutrient composition and standardized amino acid digestibility of numerous plant-based protein sources. These studies and findings proffer evidence of the suitability of plant sources of protein in canine nutrition.

In summary: 

"Dogs require specific nutrients, not specific feedstuffs." - National Research Council: Nutrient Requirements of Dogs - National Academy Press: Washington

 

 

Want to learn more about plant-based or vegan diet research for dogs?

Research & Reasons: Plant-Based Foods for Dogs

 

ABOUT THE WRITER

Tatiana Victorino. BSc, Food Engineering is Virchew's Lead - Research and Veterinary Partnerships. She received her BSc in Food Engineering at UNICAMP, an internationally recognized center of academic excellence in Brazil and also holds a BCIT Operations Management certificate. With over 5-years of professional experience working in the food and beverage manufacturing industries, Tatiana has gained a dynamic expertise in process design and improvement, lean manufacturing, business operations, quality assurance, and research and development. Tatiana's background is invaluable as she works with Virchew's Veterinary Partnerships, nutrition programs and product R&D. Got a question for Tatiana? She would love to hear from you. Fetch the answers to your questions by emailing her here: tatiana@virchew.com