What’s in Your (Vegetarian) Food?

Here we go again.

It appears that there may be more than what dog owners expect to find in vegetarian dog food.

Hold the Spam, Please: Before all of the  “Dogs are Carnivores (and a pox on your mother if you think differently)” devotees begin posting comments (in all caps ) that dogs should NOT be fed a vegetarian diet in the first place, let me state that this is not what this blog piece is about. So please, don’t even start. The point of this essay is not to argue (again…..) whether or not dogs have an absolute requirement for meat in their diet (here’s a hint: They don’t). Rather, today we examine new information about undeclared ingredients that may be present in dog food and the mounting evidence of regulatory violations within the pet food industry.

In this newest pair of studies, a team of veterinary nutritionists at the University of California tested vegetarian pet foods for label compliance and ingredient content.  I have written about this before, and unfortunately once again, the news isn’t good.


Label Compliance: In the first study, the researchers collected samples of 24 dog and cat food brands that carried a label claim of “vegetarian” (1). The majority of the foods were over-the-counter products purchased at a local pet supply store. Three products were veterinary therapeutic diets. Of the group of products, 19 were formulated for dogs or for dogs and cats, and five were formulated exclusively for cats.  Product labels were examined for their compliance with the Association of American Feed Control Official (AAFCO) model regulations, which are the basis for most state mandated pet food regulations. Pet food samples were also analyzed for total protein and essential amino acid content. Results: Of the 24 foods, only eight (33 %) were in complete compliance with AAFCO label regulations. This means that 16 brands (66 %) had one or more violations. The most common infractions were the omission of feeding instructions or caloric content, improperly reported guaranteed analysis panels, and mislabeled ingredient statements. Nutrient analysis showed that all but one of the foods met AAFCO’s minimum crude protein requirements. However, six brands had deficient levels of one or more of the essential amino acids. This means that while the total amount of protein that the food contained appeared to be sufficient, essential amino acid requirements, which are more important, were not always met.

Presence of Animal-Based Ingredients: In a second study, the same group of researchers tested 14 brands of vegetarian pet foods (2). They purchased each food on two occasions to obtain samples as duplicates from different manufacturing batches. Six were dry and eight were canned products. Samples were analyzed for the presence of mammalian DNA using an accepted laboratory technique called multiplex polymerase chain reaction (PCR). Since all 24 foods were marketed as vegetarian (and in some cases, as vegan), none included animal-based components in their list of ingredients. Results: All six of the dry (extruded) foods that were tested contained DNA from beef, pork or sheep and five of the six contained DNA from multiple animal species. These results were consistent across batches for all 7 products.  Only one of the 8 canned vegetarian foods contained animal DNA (beef) and this finding was not repeated in the second sample. In this study, the researchers also tested for the DNA of dogs, cats, goats, deer, horses, rats, mice and rabbits. DNA from these species was not detected in any of the samples. Similar to earlier studies that have found the DNA of undeclared meats in dog foods, the amount of animal-based ingredients in the foods could not be quantified. The researchers could not speculate whether the labeling violations were a result of deliberate adulteration or unintentional cross-contamination of vegetarian products with meat-containing foods produced at the same facility.


Soap Box Time: The Federal Food, Drug and Cosmetic Act requires that all pet foods sold in the United States are safe, produced under sanitary conditions, contain no harmful substances, and are truthfully labeled (emphasis mine). Perhaps I am being picky, but labeling a food as vegetarian and then not ensuring that the food indeed lacks the meat of cows, pigs and sheep, seems to qualify as not being truthful. (Some might even call it lying, I suppose). Not only are such egregious errors in violation of both FDA and AAFCO regulations, but they seriously impact the trust that dog owners have in pet food manufacturers. And rightly so.

To date, the majority of pet owners in the US continue to feed dry, extruded food. Of the dry-type vegetarian foods tested in this study, all of them, 100 % were, in fact, not vegetarian at all. This leads one to ponder about other products on the market and whether it is more the norm than the exception for dry dog foods that are sold as vegetarian to be nothing of the sort. While the authors note that this was a small number of products and so do not represent all vegetarian foods, the fact that all of the foods failed their DNA tests is alarming.

What can you do as a dog owner? Contact the manufacturer of your food and ask them how they verify the integrity of their products, specifically, the ingredients that they include in their foods. If they are not forthcoming and transparent with their response, find another producer who is. The good news is that the pressure that research studies such as these place on pet food companies and upon the industry as a whole will hopefully encourage increased transparency and improved regulatory oversight – something that we are apparently in dire need of.

Cited Studies:

  1. Kanakubo K, Fascetti AJ, Larsen JA. Assessment of protein and amino acid concentrations and labeling adequacy of commercial vegetarian diets formulated for dogs and cats. Journal of the American Veterinary Medical Association 2015; 247:385-392.
  2. Kanakubo, K, Fascetti AJ, Larsen JA. Determination of mammalian deoxyribonucleic acid (DNA) in commercial vegetarian and vegan diets for dogs and cats. Animal Physiology and Animal Nutrition 2016;  doi: 10.1111/jpn.12506.


7 thoughts on “What’s in Your (Vegetarian) Food?

  1. Pingback: Does this Seem (not…) Fishy to You? – The Science Dog

  2. Thank you for this post…I would like to know in the cats vegetarian food, where they resourced the taurine and arginine (only animal source that I’m aware of) those are essential amino acids for cats.


  3. Did the analysis differentiate between DNA from actual meat and DNA from dairy and egg? Technically, food can be vegetarian, but not vegan, if it includes dairy and egg.

    Liked by 1 person

  4. I’m one of those people who buys vegetarian/vegan food for my dog, and some people I know are freaking out about this a little – have been sent this link a couple times. But without additional information, these results don’t really bother or surprise me. This:

    “the amount of animal-based ingredients in the foods could not be quantified”

    is key. What I’m sure you know but the lay reader may not, is that PCR is a highly sensitive technology that is purposely designed to amplify the presence of tiny amounts of DNA – some assays are even advertised as being able to detect target cells at a magnitude of “less than or equal to ten to the first power” (can’t figure out how to get the superscript to display here), in other words between 1 and 10 cells. That is a TINY amount, one that does not surprise me in a food that is mixed, extruded, packaged, stored, shipped, and sold in facilities that also handle meat food. (I also note that the researchers tested for various other mammals, but did not test for human DNA. I’d be genuinely curious to see whether that would flag positive or not!)

    I really like and often recommend your blog (we’ve actually met before, at an APDT conference!), and I completely agree that the industry could use a lot more oversight, and stricter safety and labelling standards, but until there is a study with meaningful *quantitative* results, not just PCR pass/fail, I just can’t get too worked up about this. I would be angry and sad to find out I’d been paying for straight-up dead animals, but incidental cross-contamination is a fact of life when it comes to virtually any industrially processed product (probably including many of the otherwise vegan products I eat myself!) I am MUCH more troubled by the inaccurate amino acid profiles. (Which is why – and I recommend everyone do this no matter what sort of food they choose – I feed my dog a mix of foods from different manufacturers, supplemented with a variety of actual homemade foodstuffs. If one brand drops the ball slightly on any particular nutrient, the other sources can hopefully pick up the slack!)

    Anyway, thanks for continuing to research and post such interesting content (and for not demonizing veg dogs right out of the gate as so many do).

    Liked by 1 person

  5. Pingback: What’s in Your (Vegetarian) Dog Food? | M...

  6. Rather disappointing that so many labels not accurate! A couple of years ago, I was looking for a calorically dense food for my dog and had difficulty getting the calorie count for some foods.


    • Yeah, I don’t know what that’s about. As a vet I make recommendations for feeding based on, believe it or not, actual numbers, like calorie density and carbohydrate content (looking for very low carb cat diets for diabetics, for instance). The majority of canned foods have neither number on the label, and finding the numbers from the manufacturers used to be quite difficult. Luckily, most brand now have ingredients and nutrient analyses available online. Most.


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