Vegan and Vegetarian Diets for Dogs: A Word of Caution


By Michael W. Fox BVetMed, PhD, DSc, MRCVS

 In his article about feeding dogs a vegan or vegetarian diet which ethologist Dr. Marc Bekoff posted in Psychology Today ( he cites two veterinarians who do did not express any of the reservations that I have about such diets.
 Many dogs, especially German shepherds, get pancreatic insufficiency---run out of starch-digesting enzymes--- when on a high grain/starch diet. Some other breeds develop irritable and inflammatory bowel diseases and colitis --partially the gluten problem---and associated allergies from the secondary leaky gut syndrome. 

 Dysbiosis (an unhealthy population of gut bacteria) associated with biologically inappropriate diets can lead to other health problems that are rectified by dietary corrections and supplements.

 Corn and wheat can cause seizures in dogs and soy causes bloating and indigestion, indicative  of food intolerance. A high fiber diet can lead to constant hunger and malnutrition while a high carbohydrate diet can lead to obesity, diabetes, arthritis and other health problems.

 Alternative dietary inclusions such as potato, pea flour and lentils (pulses) have been recently linked with dilated cardiomyopathy in dogs. High levels of lectins in these ingredients may interfere with uptake of taurine which is an added supplement in most manufactured dog and cat foods.  
  Omega 3 and DHA (docosahexaenoic) and EPA ( eicosapentaenoic) fatty acid deficiencies and high levels of Omega 6 from corn in vegan and vegetarian diets for dogs (and people) are also a major concern. Deficiencies can underlie serious skin disorders, inflammatory conditions and are essential for the neurological and visual development of puppies. Pregnant bitches should therefore not be given biologically inappropriate and deficient diets. These fatty acids may also slow down cognitive decline in ageing animals and certainly help sustain cardiac health.
   Dogs and cats are often allergic to eggs and dairy products or have varying degrees of dietary intolerance. 
   Adding synthetic supplements to correct deficiencies in vegan and vegetarian diets can be problematic as per recent recalls of dog foods containing excessive, toxic levels of Vitamin D.
    My ultimate concern is that dogs (and cats) on biologically inappropriate diets may present clinical problems that some veterinarians will address primarily and possibly exclusively, believing that the animals are being fed an adequate diet. Treating the symptoms and consequences of improper nutrition rather than addressing the root cause has happened in many instances especially with dogs and cats being fed manufactured pet foods sold by the veterinarians who believe that the foods are no problem, along with profitable prescription diets.      
    These concerns and others about many conventional manufactured pet foods with “junk” and hazardous plant and animal ingredients condemned for human consumption are documented in the book that I co-authored with two other veterinarians, Not Fit for a Dog: The Truth About Manufactured Cat and Dog Foods. For more details and home-prepared recipes for dogs and cats, visit