Written by: Louise Calderwood | June 7, 2023
A few years ago, I was out for a walk with my dog Sherman on a late summer day along a quiet road and came across a friend repairing the fortress-like fence around her vegetable garden.
“Woodchuck after the greens again?” I asked. “NO!” she replied, clearly agitated, “The darn dog ate my carrots, it’s the second planting I have lost this year.”
Dogs are willing vegetable eaters? It turns out that many dogs will snitch vegetables and berries right out of gardens and can thrive on vegetarian or even vegan diets. This got me to questioning: what are the advantages of vegan diets for dogs and what considerations need to be made in diet formulation?
Domesticated dogs began their divergence from wolves around 20,000 to 40,000 years ago, likely when they started eating more vegetation and adapting to eating tidbits from the diets of their human cohorts. Genetic testing of the gut microbiome from dogs living about 3,500 years ago in Solarolo, Italy, suggests that they ate diets rich in starches. Proteins in the bones of dogs at an archaeological site near Barcelona, Spain, suggest that many were fed diets of cereal grains, like millet. Even modern wolves, which clearly prefer animal-based diets, eat some plant materials as they consume the digestive tracts of their prey.
But a vegan diet? Can it be done? How can dogs adapt to eating vegetarian or vegan diets?
The Association of American Feed Control Officials’ nutrient profiles for the maintenance of adult dogs includes 18% protein and 5.5% fat, values which can easily be met by a diet rich in meat, poultry, fish, eggs and dairy products. These baseline requirements can also be met through careful formulations of fruits, vegetables, legumes, nuts and grains. In some cases, veterinarians may suggest feeding vegan diets to support dogs suffering from health issues, such as pancreatitis or diagnosed food allergies, such as to dairy or eggs. Careful supplementation is required to provide the proper mix of amino acids, vitamins and minerals in the diet to assure that dogs maintain long and active lives.
Because dogs have evolved for millions of years to eat diets high in animal-based nutrients before they adapted to co-habituate with humans, special care needs to be taken in the formulation of vegan diets. The American Veterinary Medical Association notes that there is a concern for vitamin deficiencies, especially vitamin D3, which is required to support a healthy coat and skin and is only found in animal sources. Vegan diets also require careful formulation to avoid deficiencies in vitamin B, phosphorus, iron, calcium and certain essential amino acids, such as taurine and L-carnitine.
The biggest risk of a vegan diet is that it might not provide enough of the right nutrients for healthy dogs.
If owners choose to feed vegan diets to their canine pets, it is best to do so in close consultation with the company manufacturing the food, as there is currently a lack of robust data mapping the health consequences of vegan diets fed to many dogs over multiple years. While proponents of vegan diets claim benefits, there are risks associated with deficiencies of key nutrients. Extra monitoring is especially recommended if the diets are fed to growing puppies or gestating or lactating dogs.
Pet owners should weigh the environmental benefits of feeding vegan dog foods. The Pet Food Sustainability Coalition has developed The 4-Factor Framework for Sustainable Protein Evaluation in Petfood to assist pet food manufacturers in the sustainable sourcing of ingredients.
A key point of their review is that most of the animal-based ingredients found in dog foods are wholesome and nutritious portions of livestock, poultry and fish that are normally not found on humans’ dinner plates in the United States. By using these quality ingredients in pet foods, the total environmental footprint of the meat-based foods are significantly reduced. The water, land and carbon footprint of growing and transporting large quantities of perishable fruit and vegetables has an environmental impact far larger than what is commonly recognized.
In other words, using these animal-based ingredients in doggie diets helps ensure proper nutrition and reduce food waste – win-win!
As I wrapped up my visit with my neighbor, it occurred to me that I had never had to fence a dog out of a vegetable garden. Rather, the decidedly carnivorous Sherman keeps vegetable stealing varmints in check around my house.