- Hahnbee Choi, Cert. CN
Can You Feed Dogs A Vegan Diet?
Updated: Nov 7, 2022
Veganism is the practice of abstaining from animal-based foods and products. The vegan diet includes vegetables, fruits, legumes, nuts, seeds, bread, pasta, and more. The vegan diet excludes dairy, eggs, meat, and fish.
Since veganism has grown so vastly among humans, this diet has leaked into pet food. But it's questionable whether this way of feeding is benefiting pets. There have been reports of deaths and severely malnourished animals due to vegan diets. Let’s get into whether vegan diets set up dogs to thrive.
Looking at some of the most common vegan pet foods, most ingredients are corn, rice, soy, legumes, potatoes, etc. Plus, the addition of synthetic vitamins and minerals makes the food “complete and balanced.”
Although dogs are facultative carnivores and can consume plant matter, dogs require a source of complete amino acids. Complete amino acids are sources of food that provide the 10 essential amino acids that dogs require: Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine. Foods that provide complete amino acids for dogs are most abundant in animal products. Failure to provide these essential amino acids can result in malnutrition.
The most common plant protein sources that vegan pet foods and other kibble manufacturers use are very high in the glycemic index, such as brown rice. The Glycemic Index (GI) is a relative ranking of carbohydrates in foods according to how they affect blood glucose levels. Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed, and metabolized and cause a lower and slower rise in blood glucose and, therefore, insulin levels. High GI foods can induce hyperglycemia which causes oxidative stress and increases inflammation. This affects the body's insulin signaling, which can lead to insulin resistance.
Simply because a company uses plant protein and states that it provides “all nutrients” does not mean that the nutrients are bio-available and benefit the animal.
A study by the National Autonomous University of Mexico evaluated the macronutrient fatty acids and amino acids profile of vegan dog foods to the AAFCO and FEDIAF nutrient profiles. It was concluded that "all foods analyzed had one or more nutrients below the recommended levels, and some presented zinc and copper excess. Therefore, these foods should not be recommended for dogs and cats because dietary deficiencies found may lead to health risks for dogs and cats." In addition, some foods did "did not meet the minimum recommendation for methionine." Methionine is a precursor to taurine, and low amounts of these precursor amino acids have had a connection with an increase in DCM. Even when the supplement DL-methionine was added, it was still below minimum levels.
Synthetic vitamins & minerals
Synthetic vitamins and minerals are isolated nutrients that have been artificially created in an industrial matter. Vegan pet food companies must use synthetics to make their recipe “complete and balanced.” However, synthetics are less bioavailable than their whole-food counterpart. This means they are much less likely to be absorbed and utilized by the body, leading to nutrient deficiencies. While synthetics vitamins and minerals do have their place, replacing all nutrients needed with synthetics to cover essential nutrients should be avoided when possible. It's best to get nutrients from the naturally derived version, preferably from an animal source.
While plants supply a hefty amount of protein, the biological value of these nutrients to dogs is minimal. The biological value is the ability to supply the body with amino acids. The digestibility of the protein is critical as it determines the nutrient absorption of the food. When foods with low biological value are fed, the nutrients from these foods are minimally absorbed. They may boost the protein content on the label but do not provide bioavailable nutrients to the animal.
According to the Industrial Crops & Products Journal, zein, which is an industrialized protein from corn commonly used in pet foods such as Purina, tested the bioavailability through "multiple methods such as protein-corrected amino acid scores (PDCAAS), relative protein efficiency ratio (RRER), and relative net protein ratio."
In these tests, zein scored a 0-1 on the digestibility scale. When an ingredient is indigestible, that means the animal that is consuming gains no nutritional benefits. On the other hand, eggs tested and came out as 100, meaning they are a complete food for canines. While plants boost the protein content, it does not equate to vegetation being able to substitute high-quality animal products to fulfill canines' nutrient requirements.
In this chart by PetMD, the food with the highest biological value are raw, uncooked animal products, whereas the least are plant-based. Ingredients shown such as soy, rice, corn, and wheat are the most common in vegan (and some non-vegan) pet foods.
Many vegan pet food companies will add legumes as their main source of protein. Legumes are high in protein, but they are incomplete, meaning they do not supply all essential amino acids. Legumes are also abundant in anti-nutrients which inhibit the absorption of nutrients. This is why nuts and seeds must be soaked 24 hours before feeding. Soaking helps reduce the anti-nutrients and allows for better digestion.
Phytic acid is one of the many anti-nutrients in grains. Anti-nutrients are natural compounds that interfere with the absorption of nutrients. There are many anti-nutrients other than phytic acids, such as:
Glucosinolates: are found in cruciferous vegetables such as broccoli and brussel sprouts and can prevent iodine absorption.
Lectins: "legumes (beans, peanuts, soybeans), whole grains—can interfere with the absorption of calcium, iron, phosphorus, and zinc."
Oxalates: green leafy vegetables and some teas. Binds to calcium and prevents absorption
Phytates (phytic acid): the most common antinutrients found in whole grains, seeds, legumes, and nuts. Decreases absorption of calcium, zinc, magnesium, iron, and copper and interferes with the healthy gut flora
Saponins: found in legumes and grains, reduce the absorption of nutrients.
Tannins: in coffee, tea, and legumes, reduced iron absorption.
Seeing legumes, Canine Dilated Cardiomyopathy (DCM) may pop into mind. It is vital to remember that DCM is a complicated topic and is still being researched. But what is known is that genetics, incomplete amino acids, and anti-nutrients can all play a role in DCM. A diet low in amino acids plus anti-nutrients can inhibit nutrient absorption and create a disaster for a dog with a genetic predisposition. Breeds most prone to DCM are Doberman Pinchers, Golden Retrievers, Great Danes, and Boxers. There are more breeds, but more research must be conducted. If you must feed a food high in legumes, the best thing is to add real nutrients into the bowl, especially fresh animal proteins to ensure complete protein sources. This can be done with kibble boosters.
Nose to tail
Canines are biologically and psychologically designed to eat various nutrients from fresh meat, bone, and organ. The digestive system of a plant-eater is very different from a meat eater. Canines' dentition is not long, large, and wide molars of a horse, cow, or sheep. They are designed to rip, tear, and crush raw meat and bones. As the food moves further down the digestive tract, it goes into the stomach, where the stomach acids begin digestion. Canines do not produce amylase in their saliva. Amylase is an enzyme that herbivores & omnivores produce to help break down starchy carbohydrates before reaching the stomach.
In a herbivore's stomach, the vegetation it consumed would be met by more alkaline stomach acid. In contrast, the canine's stomach has a highly acidic stomach with a pH of 1-2 equipped to digest raw meat and destroy any pathogenic bacteria present in the food.
Dogs also have a higher concentration of stomach acid, which kills any bacteria. Canines are equipped with a shorter intestinal system than herbivores to give toxins and pathogens less exposure in the gut. They do not have a slow and long GI tract of a herbivore to break down and fully digest plant nutrients.
While dogs can survive on a plant-based diet, they are not designed to thrive on one. Therefore, it is very likely that the dog will be in a constant state of nutrient deprivation on a vegan diet. This is why it is vital to feed the highest quality animal-based food possible, whether raw food, cooked, or a higher quality kibble with kibble boosters. If an owner has moral conflicts with feeding an animal-based diet to a carnivorous animal, an herbivorous animal will be better suited. Raw feeding can be done in a more eco-conscious manner, and they're plenty of raw feeding suppliers that source responsibly. I hope you learned something new today & Always Keep Exploring!