Vegetarian Diets for Dogs - Good or Bad?
As vegetarian and vegan lifestyles have grown in popularity for people, I am encountering more pets being fed these diets as well. One client asked me to write about if a vegetarian diet is best for a dog specifically. First, I want to define vegetarian versus vegan and omnivore so we have a common understanding.
Vegetarian is defined as consumption of a diet lacking any meat or product of a deceased animal. Therefore, a vegetarian may consume dairy, egg, as well as nuts, legumes and plant product. A vegan is defined as consumption of only plant based product. No consumption or use of any animal based product living or not is allowed. So a vegan does not consume any egg, milk, or honey for example. An omnivore will eat other animals, animal product and vegetable matter. In the case of animals, wild dogs consume both the meat of a kill and the stomach contents which are often plant product thus being omnivores. When there is not a prey available foraging plant material is part of the diet.
How healthy is a vegetarian diet for a dog? When I am asked this question I need to have the vegetarian diet defined - is this one that has egg or milk product or is it plant only? The balance of necessary amino acids, vitamins and other agents is needed for health. What is the recipe? Is it created by a veterinary nutritionist? If this is a commercial diet is the after production analysis for nutrition performed? The AAFCO (American Association of Feed Control Officials) standards to do not require this, yet the major food manufacturers do this testing. Smaller companies test for contamination but not always digestibility, and levels of nutrient after production.
Is a vegetarian diet good or bad? Let's look at the dog's physical needs and how their digestive system has evolved. Dogs live in environments where they can hunt down prey. The sharp canine teeth are developed for biting and shredding, with molars that are not that well adapted for grinding plant material. When a group of dogs cooperates in hunt, they do not round up a plot of plant to eat. They round up animals, and eat the stomach contents that have the plant material partially digested, then the meat. In the wild, a dog would eat only every few days. Every hunt is not successful. That is why dogs have a high drive to eat - the most desirable food was not readily available daily. So when a successful hunt happened, they needed to eat up or they would miss it. Occasional grazing of plant material certainly would happen, but this is not the primary diet for the dog.
So in our modern age, is there a problem with feeding a dog a vegetarian diet? As a veterinarian, I am educated in animal nutrition, and am required to continue my education in nutrition and medicine. Over the years we know much more about the importance of needed nutrients often by the mistakes pet owners make in getting away from commercial diets. In short, when people over supplement calcium to puppies we saw a worsening of hip dysplasia in the large breed dogs. When dogs and cats are fed primarily vegetable based diets, they lack taurine and have resulting heart disease. There can be balanced vegetable based diets, but one must have a recipe developed by a veterinary nutritionist for the health needs of this pet. Unfortunately, many people run out of a supplement or needed ingredient with health problems resulting.
Commercially made vegetarian diets exist. The standards of the AAFCO standards need to be met, but that is not always a guarantee of the finished products quality. The standards apply to measurements, and recipe pre production, post production analysis is not required. The large pet food manufactures - Purina, Hills, Kal Kan, and Iams do analyze post production. They are also the leading research companies in nutrition. The pet food industry is a multibillion dollar industry. While a name, or appealing words may lead you to think this is a good product, it is the scientific evaluation that is on the technical level that will really decide this. In general, most vegetarian diets lack what a dog needs for a healthy life.
For a person who has embraced a vegetarian or vegan lifestyle, remember you are a different species than a dog or cat. Your evolution to eat a vegetable diet is based upon the evolution of many humans living as gatherers as well as hunters. If your choice is a moral decision to not consume meat, do not put this on your pets. They have physical needs that are different from yours. There may be a healthy way to provide a diet for your pet that will not cause harm but before you make this choice for your pet be sure to discuss this with a veterinarian. I have seen the sad outcome of heart failure, blindness, and chronic disease in pets fed vegan and homemade vegetarian diets. Remember this is an animal first, not an extension of yourself.