Sustainability is of growing interest not just in the human food sector, but also in pet food. This has resulted in companies releasing various vegan and vegetarian foods for our dogs and cats. Some Foods are made exclusively with plants, Some Foods are made from insects, and some foods utilize yeast. There are also a couple of companies exploring lab-grown meat.
It’s important to note that Cats are obligate carnivores while dogs are facultative carnivores or omnivores.
A common occurrence within the pet food industry is taking a course of action (Release a Product) and then figuring it out later.
Before Vegan and Vegetarian diets for our dogs and cats are considered safe long-term, some things need to be fully considered.
- Nutritional Adequacy
- Metabolomics (Metabolites)
- Nutrigenomics (Effect of Nutrition on Gene Expression)
- The Microbiome
Vegan and vegetarian dog and cat foods can be carefully formulated to meet the nutritional needs of dogs and cats as laid out by the NRC, FEDIAF, and AAFCO. However, we ultimately know very little about nutrition. All foods are much more complex than the nutrients that we track. The Risk associated with vegan and vegetarian diets is that there might be other compounds in meat that are still essential or ideal parts of our dogs and cats diets. The other health concerns to be addressed are the impact on the gut microbiome and gene expression. Additionally there is a need for more research when providing plant based versions of different vitamins.
Vegan Vegetarian Dog and Cat Foods Health Studies
Only a few studies have been conducted comparing meat-based and plant-based diets. The problem with many of them is that they were all relatively short-term studies and relatively small. This is also a problem more generally as it relates to our pets.
Some of the larger studies that have been conducted showing no change or a beneficial change in health have been online surveys. The issue with online surveys is self-selection bias can be high especially when it is a niche topic. They are also owner-reported health outcomes, not those of a veterinarian who has seen and evaluated the dog or cat. There is also the possibility that many owners might be reporting positive health outcomes because that is what they want to believe. While online shopping has made it significantly easier to acquire Vegan or vegetarian dog and cat foods, there is still the associated self-selection bias. This is a significant problem with all survey-based studies.
If this is proof that vegan and vegetarian dog and cat foods are safe and provide positive health outcomes, give me a couple of months, and I will have plenty of evidence demonstrating that fresh diets are far superior to kibble diets.
However, no one would accept this as proof that fresh diets are better, and rightfully so.
Just because an article was peer reviewed doesn’t mean it is good science, and the media reports on the study are oftentimes worse.
For a more detailed explanation on the why the vegan surveys don’t really tell us anything read our next blog post. Which will go over the studies in more detail.
Vegan and Vegetarian Dog and Cat Food Nutritional Adequacy
The opposite of these surveys is the
- Case reports of dogs and cats developing nutritional deficiencies when fed Vegan and Vegetarian Diets.
- Several studies have demonstrated that many vegan and vegetarian diets are deficient in Amino Acids, Vitamins, Minerals, and Fatty Acids for both maintenance and growth. Some were even deficient in total protein.
- These studies also don’t account for the digestibility or bioavailability of the nutrients
- Or the degradation of nutrients during transport and long-term storage.
While on the one hand, yes, Vegan and Vegetarian Dog and Cat Foods can be formulated to meet the bare minimum nutrient requirements laid out by AAFCO, The NRC, or FEDIAF. Some of them aren’t hitting the minimums. The same can be said of many commercial fresh foods, particularly the companies selling ratio diets.
While yes, manufacturers could add more Amino Acids, Vitamins, Minerals, and Fatty Acids to make them adequate based on current understanding.
Issues with Supplemental sources of Required Nutrients
The issue, however, is that supplemental sources are not always as great. As multiple recalls (Vitamin D Recall of Hills, Midwestern Pet Food, Sunshine Mills) have demonstrated over the past several years, they do carry the Risk of excessive levels of nutrients.
This might be a more significant issue with vegan and vegetarian foods. As many of the foods we have looked at have an even longer list of added vitamins and minerals than many traditional dry foods.
Current Knowledge on the Nutritional Needs
In the grand scheme of nutrition, we know almost nothing about the nutritional needs of our dogs and cats.
AAFCO, FEDIAF, and the NRC are only concerned with a very small percentage of nutrients for dogs and cats. Total Protein, 10-13 Amino Acids. Total Fat, 3-5 Fatty Acids, 12 Minerals, and 12 Vitamins. While the various food databases commonly track around 150 food compounds.
There is a genuine possibility that other nutrients are essential; we just don’t know it yet, as it hasn’t been investigated.
For Example, some research indicates that C:15 Pentadecanoic Acid might be an Essential Fatty Acid for humans.
There may be other essential nutrients, conditionally essential, or nutrients that are ideal inclusions to helping our pets thrive. After all, the Nutrient profiles are based on the bare minimum not to develop a deficiency(negative health consequence), not what levels are ideal for helping our pets live a long and healthy life.
This ultimately means that there could be other essential or ideal nutrients within meat that could be deficient in vegan or vegetarian dog or cat foods.
For example no studies have been conducted looking to see what happens when feeding a diet completely void of Carnitine, or CoQ10.
It’s very possible if these studies where to be conducted that they would be deened as essential nutrients. It could be a very small amount such as .1 micro gram or it could be larger, but there is no way to know without conducting the study.
Unfortunately given the state of funding for canine and feline nutrition research, these studies are unlikely to happen anytime in the near future.
Metabolomic Comparison of Plant-Based Burger vs. Beef Burger
In one study that compared a grass-fed beef to a fortified plant-based burger with similar nutrient panels, they found that out of the 190 named compounds, 171 (90%) of them were significantly different.
Some are essential nutrients while others are not, but they all likely play some role in the health of our companions. Many of them likely act synergistically with each other.
|22 Compound||Exclusively in Beef|
|51 Compounds||Higher in Beef|
|67 Compounds||Higher in Plant Based|
|31 Compounds||Exclusively in Plant Based|
The Full list of Compounds is available to download here.
The compounds found either higher or exclusively in Plant-based were primarily phenols, tocopherols, and phytosterols. This is something that would be anticipated as they are coming from plants.
While many of the compounds found to be higher or exclusively in the plant-based burger can be beneficial inclusions, this would also represent a drastic shift in the 73 other compounds found exclusively or in higher amounts within the beef.
We shouldn’t ignore the other compounds not tracked
These other compounds should not be ignored as many of them are still physiologically important. They have also been a part of our dog’s and cat’s diets for much of their evolutionary history. So we should exercise caution before inadvertently reducing or eliminating them from their diets.
We don’t need to repeat the mistakes of Taurine for cats, where it wasn’t essential until many cats started developing DCM and suffering from retinal degeneration.
While they might taste similar, the nutrient panels may be similar. They are still very much not the same thing nutritionally. A Plant-based burger can be fortified, but there will always be other nutrients or compounds missing.
All of the other compounds found within foods that we don’t account for is one of the primary reasons why we strongly recommend rotating between different foods and treats. So, they can receive a wider array of these other compounds.
Diet is one of many factors that influence how genes are expressed. By drastically altering the diets of our dogs and cats to vegan or vegetarian diets, there is a strong chance that there will be some change in the way some genes are expressed. This could be a good thing or a bad thing, but we likely won’t know for some time.
- There are also possible epigenetic implications for those dogs and cats intended for breeding.
Research is increasingly showing that the gut microbiome plays a profound role in the health of our dogs and cats. Diet plays a direct role in the bacterial composition of the gut microbiome. Such a drastic alteration in the diet of our dogs and cats is likely to alter the microbiome. It could be positive; it could be negative. We just don’t know.
Other Issues with Vegan or Vegetarian Diets for Dogs and Cats
Another issue with plant-based diets is that they are often high in antinutrients such as phytates, lectin, tannins etc. These can directly influence the absorption of other nutrients. So, while the nutrients might be present in the correct amount on paper, they still end up being deficient due to said antinutrients.
Antinutrients represents one of the biggest risk factors of vegan pet foods, as many have already been shown to not be complete and balanced. This means for the vegan pet foods barely meeting the minimum when the effect of anti nutrients is taken into account they may no longer be meeting the minimum.
Dogs can meet their Vitamin A Requirement from Provitamin A while Cats cannot. This is most likely a result of their more carnivorous evolutionary history.
While research for dogs is relatively limited, a human study found the conversion of Vitamin A from the Provitamin A of various plants ranged from 3.6 to 1 all the way to 28 to 1. This is a fairly large range. Vitamin A Conversion also appears to be influenced by
- Amount of Vitamin A in the diet,
- Amount of fat in the diet (Vitamin A is Fat Soluble),
- BMI (the closest thing for dogs and cats is BCS)
Most foods contain more than enough Vitamin A to satisfy a dog’s Vitamin A requirement, so research regarding the conversion of plant based provitamin A hasn’t been a pressing concern, but when discussing Plant-based diets, where all or most of the vitamin A will be coming from provitamin A it does become much more neccessary.
Vitamin D comes in many forms the primary forms being vitamin d2(from plants) and d3(from animals). Almost all the research around vitamin d requirements has centered around vitamin d3.
I would be remiss not to mention that the meat industry funded the food comparison study. However, at the same time, some of the vegan/vegetarian studies have been funded by organizations advocating for vegan and vegetarian diets.
So far no studies have been conducted to my knowledge directly comparing a vegan or vegetarian dog or cat food with a food containing common or traditional pet food ingredients. So this is the closest thing we have so far.
While plant-based foods might be able to get close to animal-based products, they are not a direct replacement even when fortified. Nutrition is not a vacuum. It isn’t as simple as just making sure that we are providing our pets with the right amount of specific nutrients.
For a long time, Taurine wasn’t considered essential for cats, and now it is. There is a decent chance that as more is learned, other nutrients will be considered essential or beneficial to our dogs and cats.
While many of the ingredients found in vegan pet food are already present in many other traditional Pet Foods they have not been evaluated at these higher inclusion rates.
At the end of the day, the minimum nutrient requirements can only be based on what is known now, and in the grand scheme of nutrition, very little is ultimately known.
That does not mean we should ignore the nutrient guidelines as they are now, but there will likely be more personalized nutrition taking genetics into account in the future.
Ultimately Vegan and Vegetarian diets for our dogs and cats represent a gamble that the other compounds within meat are not an essential or ideal part of their diet.
Long Term Effects
Vegan and Vegetarian diets are still relatively uncommon and new. So, there isn’t much health data on these diets.
There is a good chance that no effect will be noticed in the short to medium long term, but that doesn’t mean there is none.
It could have a major impact long-term or a relatively minor impact, and we probably won’t know until dogs and cats have been fed these diets for their entire life.
While all of this is important for adult dogs and cats it is probably even more important for puppies and kittens, as well as those who are pregnant or nursing.
It’s possible that the Golden Retriever Lifetime Study might shed some light on the long-term effects of Vegan and vegetarian diets for dogs, just as it may also be able to shed some light on any benefits of a fresh food diet. The other possibilities are VCA or Banfield (The largest Animal Hospitals in the US) or the Royal Veterinary College program VetCompass (UK).
Questions to Ask Vegetarian and Vegan Dog Food Manufactures
If you are feeding a plant-based or insect-based food, ask the manufacturer
- What sort of feeding trials have they conducted on the food?
- Adult, Puppies/Kittens, Nursing or Pregnant Dogs and Cats
- While many, if not most, pet foods have not conducted feeding trials, we would say that this is even more imperative for foods and diets that are vastly different.
- It’s important to remember feeding trials only need to be 26 weeks, include a minimum of 8 dogs of which 75% must complete the trial. Additionally, the number of tests required is limited. Read more about why feeding trials (the gold standard) are ultimately inadequate here.
- Ask them for a typical nutritional analysis showing that it, at the very least, meets the bare minimums.
- Ask them how they accounted for the antinutrients found in the food.
- Ask them about what digestibility studies they have conducted.
Dodd, S., Adolphe, J. L., & Verbrugghe, A. (2018). Plant-based diets for dogs. Journal of the American Veterinary Medical Association, 253(11), 1425–1432. https://doi.org/10.2460/javma.253.11.1425
Dodd, S., Shoveller, A. K., Fascetti, A. J., Yu, Z. Z., Ma, D., & Verbrugghe, A. (2021). A Comparison of Key Essential Nutrients in Commercial Plant-Based Pet Foods Sold in Canada to American and European Canine and Feline Dietary Recommendations. Animals : an open access journal from MDPI, 11(8), 2348. https://doi.org/10.3390/ani11082348
Kanakubo, K., Fascetti, A. J., & Larsen, J. A. (2015). 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, 247(4), 385–392. https://doi.org/10.2460/javma.247.4.385
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van Vliet, S., Bain, J.R., Muehlbauer, M.J. et al. A metabolomics comparison of plant-based meat and grass-fed meat indicates large nutritional differences despite comparable Nutrition Facts panels. Sci Rep 11, 13828 (2021). https://doi.org/10.1038/s41598-021-93100-3
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