Are vegan diets for pets as unhealthy as claimed? Here’s what the evidence says

The impact of vegan diets on the health of our pets is generating heated debate from people on both sides.

But so far, we haven’t had a formal assessment of the scientific evidence. In new research published today in Veterinary Sciences, we’ve brought together the results of 16 studies on the health of dogs and cats fed vegan diets.

So if you’re wondering if 2023 could be the year your best (pet) friend embraces a meatless lifestyle, read on to find out the benefits and risks, and what we still don’t know.

Ethical food?

In recent years, people in many parts of the world have increasingly adopted vegetarian or vegan diets, spurred by ethical concerns for animal welfare, sustainability or based on perceived health benefits.

Pet owners may also wish to feed their pets according to these dietary choices. In fact, one study found that 35% of owners who didn’t feed their pets vegan diets would consider them, but found too many barriers. The main concerns were nutritional adequacy, lack of veterinary support, and few commercially available vegan diets.

It has traditionally been considered that the vegan diet of primarily carnivorous species goes against their “nature” and has serious health implications.

There has even been a debate about whether feeding vegan diets to pets amounts to animal cruelty. But what does science really say?

Descended from ferocious desert predators, cats are obligate carnivores – they need meat in their diet and cannot digest plants.
small plant/Unsplash

Necessary nutrients

Dogs and cats are carnivores. Dogs are facultative carnivores, meaning they can digest plant material and survive without meat, but may not thrive.

Cats, on the other hand, are obligate carnivores. By definition, this means their diet is over 70% meat and they cannot digest plant matter.

The gut anatomy of dogs and cats also clearly indicates their carnivorous lifestyle. Their teeth are designed to crush and grind meat and hold prey. Their intestines are also short with less capacity relative to body size since, unlike herbivores, they do not need to ferment plant matter to digest it.

Read more: Pet foods made with raw meat may not be good for your dog or your own health

One of the main concerns with vegan diets for pets is that grain or soy proteins (the main plant proteins) contain fewer essential amino acids, for example omega 3 fatty acids or taurine, and do not contain not all essential vitamins. These nutrients are needed to maintain good heart, eye and liver function.

A series of studies have examined the nutritional composition of vegan diets for pets and some are insufficient. Homemade vegan diets are particularly at risk of being nutritionally deficient, but some commercial diets may also not meet the requirements set by various nutritional guidelines for pets.

But all of this considers vegan diets using an input-based approach – it’s based on predictions. If we really want to know the impact of these diets on health, we have to measure it in animals.

A brown puppy on a tiled floor with his nose in a stainless steel bowl
Dogs are facultative carnivores, which means they could theoretically survive without meat, but that’s not the same as thriving.
New Africa/Shutterstock

The evidence is lacking

We performed a type of study common in evidence-based practice called a systematic review. These studies provide a summary of all research on a topic; its quality is assessed, allowing us to assess how certain we can be when making evidence-based recommendations.

Only 16 studies have looked at the health effects of vegan diets in dogs and cats. Cats were only included in six of them, despite being the species most likely to suffer from nutritional deficiencies.

A number of these studies used owner reports of health as a measured outcome, such as perceived health or body condition. These are likely to be subjective and could be subject to bias.

In the few studies that measured health directly by examining animals or performing laboratory tests, there was little evidence of adverse health effects from vegan diets for pets. Nutrient levels were generally within the normal range, no heart or eye abnormalities were detected, and body and coat condition were normal.

However, it is important to note that these studies often involved small numbers of animals, with vegan diets only given to the animals for a few weeks – so the deficiency may not have had time to set in. develop. In addition, study designs were often considered less reliable in evidence-based practice, for example without a control group used as a comparison.

Owners’ perceptions of the health benefits of the diets were overwhelmingly positive. The benefits cited were reduced obesity, better smelling breath and reduced skin irritation. The only downside was the increased fecal volume, which seemed tolerable for most owners.

A kelpie holding an orange ball looking excitedly at the camera
Many animals included in studies of vegan pet feeding did not appear to suffer from adverse effects, but the quality of evidence was low.
Sarah Brown/Unsplash

Proceed with caution

All in all, it seems the jury is still out on whether or not feeding our four-legged carnivorous friends vegan food is actually safe.

What we can be sure of is that strong arguments for or against vegan pet feeding are potentially flawed and unsupported by evidence.

For now, owners who commit to feeding their pets a vegan diet should take a cautious approach. Use a complete and balanced commercial vegan diet formulation and schedule regular health checks with a veterinarian.

Read more: Five ways to help your dog live a longer, healthier life

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