Dilated Cardiomyopathy in Pets and Grain-Free Diets

November 19th 2020

What is Dilated Cardiomyopathy?

Dilated Cardiomyopathy (DCM) is a heart condition where the heart muscles are weakened due to various factors including infectious disease, age, nutritional deficiencies and genetics. DCM decreases the hearts ability to contract efficiently and as the disease progresses this can lead to secondary cardiac problems.

Grain-Free Pet Food: A little bit of background

Grain-free diets have become increasingly popular in the past 5 years, making them almost one of the top go-to foods for pets suffering with allergies, intolerances and skin/ gastrointestinal conditions.

Grain-free foods contain non grain-based carbohydrates like potato, sweet potato, tapioca and peas and may be paired with a novel protein, which is a single protein source that isn’t commonly found in most pet foods. Novel proteins such as duck, pork, lamb and venison are typically used.

Dilated Cardiomyopathy: What’s the fuss about?

Over the past few years cardiologists in the United States began to see increased cases of DCM in dog breeds that had no known genetic predisposition to the disease i.e., occurring in breeds that weren’t normally associated with the disease.

They conducted some preliminary research and concluded that a common factor among these pets was that they were all fed a grain-free diet. Discussions then started about whether the grain-free diets were causative factor and what specially within in the diet may be causing an issue; could it be related to taurine levels in the diet? Or the legumes included as carbohydrates? And many more questions arose so it was clear that further investigation was required.

The FDA (Food and Drug Administration) then started to investigate the issue and in 2018 they released an interim statement detailing the possible links between pets that are fed grain-free diets and DCM. Their belief is that the link is based on high percentages of legumes, peas, potato and other pulses in the grain-free diets, but they have qualified that this needs further investigation.

What does Taurine have to do with it?

Taurine is an amino acid that is required for multiple body functions, including helping the heart to maintain its normal function. If animals are deficient in taurine this can lead to many problems in the body, one of the most common is causing problems with the heart.

Most dogs don’t require taurine supplementation because they can synthesise it themselves from other amino acids, although it is suspected that some breeds might require more taurine in their diets than others. Cats on the other hand are unable to synthesise taurine themselves so they require supplementation from their diet.

This became evident in the 1980s, when Veterinary Surgeons were reporting increased incidences of DCM in cats. A small initial study showed twenty-one cats who had low plasma levels of taurine consequently had clinical signs of DCM. Once the cats were supplemented with taurine they started to recover from the disease.

Taurine is found to have naturally high levels in animal-based proteins but is not present in plant-based proteins like peas, lentils and other legumes, which has contributed to some of the recent concerns about grain-free diets and DCM.

Feeding a diet that has high levels of quality animal protein should ensure an adequate intake of taurine. If the animal protein used is of a low quality or has been overcooked at high temperatures it can mean that the protein is harder for the animal to digest, reducing the levels of taurine the animal received from the food.

What are the actual facts?

The FDA have published some of their early research with the information they have from the owners of DCM affected pets. From the five hundred and twenty-four cases reported they can conclude that the most commonly fed protein in these cases was chicken, followed by lamb.

There was some correlation between specific breed types having a genetic predisposition to heart conditions, with golden retrievers being the most commonly affected dog breed, who may be predisposed to a taurine deficiency which could then lead to DCM. However, the FDA does suspect that the high levels of golden retrievers reported was due to online groups of golden retriever owners raising awareness and urging others to report to the FDA.

Out of all the cases reported, four hundred and fifty-four (87%) of these were fed dry grain-free diets. The characteristics of the diets involved with the cases were grain-free (containing no soya, wheat or barley) and had high levels of peas and lentils. It is important to note that no cases have been noted in Europe or the UK and at the moment appear to be limited to the US.

Most UK formulations are different to diets made in the states and have to conform to different nutritional standards. They are also manufactured with nowhere near the levels of legume level of those diets found in the states.

What is the best advice?

The link between DCM and grain-free diets is still being investigated and researched, this is all in its very early stages and no conclusions about the possible causes have been made. The FDA are now investigating, as well as several university cardiology and nutrition specialists in the states who are independently researching the matter. Links to their websites can be found here.

If you are concerned about what you are feeding your pet, the best advice you can follow is the advice of your own veterinarian. Grain-free diets can be really good for dogs with specific sensitivities; however, many dogs will do just as well on a well-balanced hypoallergenic diet.