The Rise of Sustainable Pet Food: Are Vegan and Vegetarian Diets Safe?
As sustainability becomes a growing priority in the pet food industry, companies are introducing more plant-based, insect-based, and yeast-derived diets for dogs and cats. Some brands are even exploring lab-grown meat as an alternative protein source.
However, it’s crucial to recognize the fundamental dietary differences between species:
- Cats are obligate carnivores, meaning they require meat to survive.
- Dogs are omnivores and can adapt to a wider range of foods, but their long-term health on a plant-based diet remains uncertain.
The pet food industry has a history of launching new products first and addressing potential concerns later. Before fully embracing vegan and vegetarian pet diets, several key factors must be carefully evaluated:
- Nutritional Adequacy – Do these diets meet essential nutrient requirements
- Metabolomics – How do plant-based diets impact metabolic health?
- Nutrigenomics – What effects do they have on gene expression?
Without thorough, long-term research, feeding vegan or vegetarian diets to pets remains an experiment—one that could have unknown consequences.
TL;DR
Vegan and vegetarian pet foods can be formulated to meet the minimum nutritional standards set by NRC, FEDIAF, and AAFCO. However, nutrition is complex, and our understanding is still evolving. Meat contains compounds that may be essential or beneficial for long-term health, which plant-based diets could lack. Additionally, these diets may have unknown effects on the gut microbiome and gene expression, raising concerns about their long-term impact on dogs and cats.
Health Studies on Vegan and Vegetarian Pet Diets
Research comparing meat-based and plant-based diets for pets is limited, and most existing studies are small and short-term. This makes it difficult to draw definitive conclusions about the long-term health effects of vegan and vegetarian diets for dogs and cats.
Some larger studies suggest no negative health impacts—or even potential benefits—but these are primarily owner-reported online surveys, which come with significant self-selection bias. Owners who choose plant-based diets for their pets may be more likely to report positive outcomes, whether consciously or unconsciously. Additionally, these surveys rely on personal observations rather than veterinary evaluations, further limiting their reliability.
If online surveys were considered solid proof, it would be just as easy to gather data "proving" that fresh diets are superior to kibble—but anecdotal evidence alone is not enough.
It’s also important to remember that peer-reviewed does not always mean high-quality science, and media reports on studies often oversimplify or misrepresent findings.
For a deeper dive into why current studies on vegan pet diets don’t provide definitive answers, stay tuned for our next blog post, where we analyze the research in detail.
Nutritional Adequacy of Vegan and Vegetarian Pet Diets
While some studies and surveys suggest that plant-based pet diets can be nutritionally sufficient, case reports tell a different story—showing instances where dogs and cats developed nutritional deficiencies on vegan and vegetarian diets.
Research has found that many plant-based pet foods lack essential amino acids, vitamins, minerals, and fatty acids required for both maintenance and growth. Some even fail to meet basic protein requirements. Additionally, these studies don’t account for:
- Nutrient digestibility and bioavailability – Just because a nutrient is listed on the label doesn’t mean the body can absorb and use it efficiently.
- Nutrient degradation over time – Long-term storage and transport can reduce nutrient levels, making the food less complete than intended.
While it’s possible to formulate vegan and vegetarian pet foods to meet the minimum standards set by AAFCO, NRC, and FEDIAF, some products still fall short—just as some commercial fresh foods do, particularly those using ratio-based formulations.
Manufacturers can add synthetic amino acids, vitamins, and minerals to compensate, but this approach relies heavily on current nutritional knowledge, which is still evolving.
Understanding Nutritional Needs: How Much Do We Really Know?
When it comes to canine and feline nutrition, our knowledge is still extremely limited. While food science has identified thousands of compounds in various ingredients, pet nutrition guidelines—such as those from AAFCO, NRC, and FEDIAF—focus on only a small subset of known nutrients.
For example, these regulatory standards track:
✔ Total protein and 10–13 amino acids
✔ Total fat and 3–5 fatty acids
✔ 12 minerals and 12 vitamins
However, food databases, like FoodDB, catalog over 70,000 compounds found in different foods. This raises a critical question: Are there other essential or beneficial nutrients in meat that we simply haven’t identified yet?
One example is C:15 pentadecanoic acid, which recent research suggests may be an essential fatty acid for humans—yet it was not previously recognized as such. Similarly, we have no studies examining the long-term effects of feeding dogs or cats diets completely devoid of creatine, carnitine, or CoQ10, compounds naturally found in meat. If studied, some of these may turn out to be essential as well.
The Difference Between Meat and Plant-Based Diets
A metabolomic comparison between grass-fed beef and a fortified plant-based burger—despite both having similar nutrient panels—found that out of 190 named compounds, 171 (90%) were significantly different:
- 22 compounds were found exclusively in beef
- 51 compounds were present at higher levels in beef
- 67 compounds were present at higher levels in plant-based foods
- 31 compounds were exclusive to plant-based foods
While the plant-based diet was richer in phenols, tocopherols, and phytosterols—compounds with known health benefits—it also lacked 73 other compounds that were present in higher amounts in meat. Many of these compounds likely interact synergistically, influencing metabolism, immunity, and overall health in ways we don’t yet fully understand.
The Importance of Untracked Nutrients
Many compounds in food go unaccounted for in standard pet nutrition guidelines, yet they may still play crucial roles in health, metabolism, and longevity. These nutrients have been part of dogs’ and cats’ diets for thousands of years, and eliminating them without fully understanding their importance could have unintended consequences.
We’ve seen this before—taurine wasn’t initially recognized as essential for cats until deficiencies led to dilated cardiomyopathy (DCM) and retinal degeneration. By the time the issue was identified, many cats had already suffered serious health problems.
While plant-based foods may be fortified to match the basic nutrient profile of meat-based diets, they aren’t identical. A plant-based burger may mimic the macronutrient breakdown of beef, but it will always be missing certain natural compounds that we have yet to fully understand.
This is why dietary variety is essential. By rotating different foods and treats, pets are exposed to a wider range of nutrients, reducing the risk of unknowingly omitting something vital.
Nutrigenomics: How Diet Influences Genes
Diet plays a significant role in gene expression, meaning what we feed our pets can influence how their bodies function at a genetic level. A drastic shift to a vegan or vegetarian diet could alter gene activity in ways we don’t yet fully understand—for better or worse.
For breeding animals, there may also be epigenetic implications, meaning dietary changes could potentially affect future generations. However, research in this area is still in its early stages.
Potential Risks of Vegan and Vegetarian Diets for Dogs and Cats
Antinutrients: Blocking Nutrient Absorption
One of the biggest challenges with vegan pet foods is the presence of antinutrients—compounds like phytates, lectins, and tannins that can interfere with the absorption of essential nutrients. While a food may appear nutritionally complete on paper, antinutrients can reduce bioavailability, leading to deficiencies over time. This is especially concerning given that many plant-based pet foods have already been found to be deficient in key nutrients.
Vitamin A: Conversion Challenges
- Dogs can convert provitamin A (found in plants) into active vitamin A, but the efficiency varies widely.
- Cats cannot convert provitamin A at all, meaning they require preformed vitamin A from animal sources.
In humans, research has shown that provitamin A conversion rates range from 3.6:1 to 28:1, depending on factors like:
✔ The amount of vitamin A in the diet
✔ The amount of fat in the diet (since vitamin A is fat-soluble)
✔ Genetics and body composition (BCS in pets)
While dogs can theoretically obtain vitamin A from plants, conversion efficiency is highly variable and has not been well studied—raising concerns for dogs on long-term vegan diets.
Vitamin D: D2 vs. D3
- Vitamin D3 (the preferred form) is found in animal-based ingredients.
- Vitamin D2 (found in plants) is commonly used in vegan diets.
Most research on vitamin D in pets has focused on D3, not D2, meaning we don’t fully understand how well dogs and cats process plant-based vitamin D. Without further studies, it’s unclear whether a diet relying primarily on D2 can provide the same long-term health benefits.
Conclusion: The Unknowns of Vegan and Vegetarian Pet Diets
It’s important to acknowledge that bias exists on both sides of the debate. While the meat industry has funded some studies comparing plant-based and animal-based diets, many vegan and vegetarian studies have been backed by organizations promoting plant-based nutrition.
As of now, no comprehensive studies directly compare a vegan or vegetarian pet food to a traditional meat-based diet using common pet food ingredients. This means we are still lacking definitive, long-term research on the true impact of plant-based diets for dogs and cats.
While fortified vegan diets may come close to replicating the nutrient profile of meat, they are not identical replacements. Nutrition is far more complex than simply meeting baseline nutrient requirements—there are likely undiscovered compounds in meat that contribute to long-term health.
History has shown us that nutritional science evolves over time. Taurine wasn’t always recognized as essential for cats, and its absence led to serious health issues before it was formally acknowledged. It’s entirely possible that future research will uncover other essential or conditionally essential nutrients that are missing in plant-based pet foods.
At the end of the day, nutritional guidelines are based on what we know now, but in the grand scheme of things, our understanding of pet nutrition is still limited.
Vegan and vegetarian diets for pets are ultimately a gamble—one that assumes there are no essential or ideal nutrients in meat that science has yet to identify. While plant-based diets may be suitable for some pets in the short term, long-term effects remain unknown. As research continues to evolve, a more personalized approach to pet nutrition, considering genetics and individual needs, will likely become the future of optimal feeding.
Key Questions to Ask Vegan and Vegetarian Pet Food Manufacturers
If you’re considering a plant-based or insect-based diet for your pet, it’s crucial to ask the manufacturer the right questions to ensure nutritional adequacy and safety.
✔ Have you conducted feeding trials?
- Were trials done on adult dogs and cats, puppies/kittens, or pregnant/nursing animals?
- Many pet foods skip feeding trials, but they are especially important for diets that differ significantly from traditional formulations.
- Keep in mind that AAFCO feeding trials only last 26 weeks, require just 8 animals, and only 6 need to complete the trial—which is a very limited standard for long-term health assessment.
✔ Can you provide a full nutritional analysis?
- Does the food at least meet the minimum requirements set by AAFCO, NRC, or FEDIAF?
- How do they ensure consistent nutrient levels throughout production and storage?
✔ How have you accounted for antinutrients?
- Plant-based ingredients often contain phytates, lectins, and tannins, which can block nutrient absorption.
- What steps have been taken to reduce the effects of these compounds?
✔ Have you conducted digestibility studies?
- Nutrient content on paper doesn’t guarantee absorption.
- Have they measured how well dogs and cats can actually digest and utilize the nutrients in their formula?
By asking these questions, you can better evaluate the quality and safety of a plant-based pet diet before making a decision.
References
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
Tang G. (2010). Bioconversion of dietary provitamin A carotenoids to vitamin A in humans. The American journal of clinical nutrition, 91(5), 1468S–1473S. https://doi.org/10.3945/ajcn.2010.28674G
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
Zafalon, R., Risolia, L. W., Vendramini, T., Ayres Rodrigues, R. B., Pedrinelli, V., Teixeira, F. A., Rentas, M. F., Perini, M. P., Alvarenga, I. C., & Brunetto, M. A. (2020). Nutritional inadequacies in commercial vegan foods for dogs and cats. PloS one, 15(1), e0227046. https://doi.org/10.1371/journal.pone.0227046