Does grain free diets cause heart disease in dogs?

In July this year, the US FDA released an alert saying that the numbers of dogs presenting with canine DCM (dilated cardiomyopathy) has increased in recent years. Specifically, the alert warned that incidence numbers had increased in dog’s who don’t have a genetic predisposition to the condition.

Further investigation led to the discovery that a large portion of non-predisposed dogs who developed DCM had decreased levels of taurine, an amino acid that plays an important role in many bodily functions. And that this taurine-deficiency could be a result of these dogs consuming foods that are high in potatoes, peas, lentils and other legumes.

Clearly this is an important issue if the FDA are releasing an alert. But what are the grounds on which the alert was based, and perhaps more importantly what can and should you, as a dog owner, know and do based on it.

What is taurine

Taurine is a sulphur amino acid found in most animal tissue, in particular the organs (heart, kidney, liver).

Your dog needs taurine for healthy reproduction, healthy eyesight and hearing. It is an important antioxidant as well as a component of bile acid. It also works by regulating calcium flow into and out of the cells.

But perhaps one of the biggest areas where we know taurine plays a vital role is in ensuring normal, healthy cardiovascular function. Put simply, it helps ensure your dog’s heart is working properly.

Taurine deficiency in dogs – predisposition vs induced 

Unlike cats, dogs have the ability to make taurine themselves. They do this by converting and changing other amino acids that are present in the body into taurine.

However, there’s evidence to show that certain breeds of dog are predisposed to having a taurine deficiency, either because of their genetic make-up or because of their size.

Breeds that are known to be genetically pre-disposed to taurine deficiency include Cocker Spaniels, Newfoundlands, Great Danes, Boxers and Doberman pinchers. The cause for this pre-disposition isn’t fully understood and how it manifests itself in each breed varies. For example, some breeds have a higher requirement for this amino acid than others, while other breeds don’t synthesise or utilise taurine properly.

This latter point is related to the second reason some dogs have lower levels of taurine – their size. Larger adult dogs can have naturally lower levels of taurine due to having a lower metabolic rate, meaning synthesis of this amino acid is impaired. For example, Newfoundlands have a far lower rate of taurine synthesis when compared to Beagles.

But based on this latest FDA alert, we now know that irrespective of their genetic make-up or size, dogs who are primarily fed diets that are high in potatoes, peas, lentils and other legumes are also at risk of becoming deficient in taurine.

Health ramifications of taurine deficiency

So, what’s the downside of being taurine deficient? Given the fact that this amino acid plays an important role in many different processes, particularly ensuring a healthy heart, it’s not surprising that a deficiency in it can lead to a variety of health problems.

Perhaps the most well documented of these problems, and the one that forced the FDA alert, is an increase in DCM (dilated cardiomyopathy).

DCM is a serious condition of the heart muscle, which overtime results in the chambers of the heart becoming enlarged (or dilated). Enlarged heart chambers means it’s harder for the heart to pump, which can cause vales in the heart to leak. This leads to a build-up of fluids in the chest and ultimately results in congestive heart failure.

But what’s that got to do with a grain-free diets I hear you ask?

The common thread in DCM cases reported to the FDA is dogs eating diets high in potatoes, peas, lentils and other legumes – ingredients often found in diets labeled as grain-free.

As a result, it didn’t take long for the dog world to start targeting grain-free diets and implying that these foods are causing taurine deficiency-related DCM in dogs.

However, although FDA identified foods that are often found in grain-free diets, The FDA also stated that it is not yet clear how these ingredients may be connected to DCM in dogs.

It is quite possible there’s something about the high carbohydrate content in these diets that depletes taurine levels. The problem might be processing method, main ingredient sourcing, unbalanced diets or other factors could be involved.

We still have a great deal to learn about diet associated DCM and we will have to wait for more information on the subject before we know precisely what is happening.

It’s important to note too that this isn’t about never including potatoes, lentils, peas or other legumes, in your dog’s diet – it’s about including them in moderation, the same as everything else.

It’s also worth noting that grain-free diets did not develop in response to new scientific research. Instead, it was because dog owners wanted them. You can read more here.

What can and should you, as a dog owner, do based on it

Using the knowledge that we do have, my recommendation is to choose a food made by a well-known company with a long track record of producing good quality diets. The company should have a board certified veterinary nutritionist on staff, not just a veterinarian.

Familiarise yourself with a variety of ingredients and what the labels on a dog food tells you. You can learn more here.

Look for a food that contains high-quality, animal protein sources such as meat, fish, eggs etc. Avoid foods that include plant protein such as pea protein, corn gluten, wheat gluten etc. as primary protein source.

Never use dog food recipes found in books or online. If you prefer homemade, consult with a qualified nutritionist. He or she will use a computer software to formulate you dog’s diet and balance it as necessary to meet NRC guidelines. I do this, but you can also speak to your vet about a veterinary nutritionist.

If you do have concerns about your dog’s taurine levels, or about them potentially showing signs of DCM, the best thing to do is speak to your vet.

Learn more

Grain-free, the latest trend in dog food

Diet for dogs with heart disease

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