Grain-Free Dog Food and Cardiomyopathy – What We Know

As a pet parent, you probably want to know more about the role of grains in pet foods, and the questions around grain-free dog food. Concerns around grain-free diets first started with the Food and Drug Administration’s (FDA) statement in 2018 about dilated cardiomyopathy (DCM). The FDA told the public that there was an increasing number of reports of DCM in dogs, possibly linked to grain-free dog foods. More studies were needed to understand if there was a risk associated with feeding dogs grain-free foods containing potatoes or pulses. In this article, our pet nutrition specialist has provided an outline of the resulting research available on grain-free dog food and cardiomyopathy.

What are pulses, and why are they used?

Pulses are dry-harvested legumes, including beans, peas, chickpeas, and lentils. Legumes that are rich in fat or moisture at the time of harvest, like soybeans and peanuts, are not pulses. Fresh beans and peas are also not pulses. In short, all pulses are legumes, but not all legumes are pulses!

Pet foods have relied on pulses in their recipes for decades. They are a popular ingredient because they have greater protein and fibre content than grains like rice, corn, and sorghum. These are great characteristics for pet food! Pulses increase dietary protein content and help with gut health and weight management. They are a good complementary protein source when added to other ingredients. You will find pulses in the ingredient list.

What can be bad about pulses?

Pulses alone don’t contain all the nutrients dogs need in a protein. They contain lower concentrations of sulfur amino acids (methionine and cysteine), and lack taurine, which is normally found in animal products and some kinds of algae. Low taurine levels are known to be linked with DCM. However, when combined with other ingredients, pulses complement the nutritional profile of a dog food.

What is DCM, and what causes it?

DCM is a heart condition that results in a decreased ability to pump blood effectively. As mentioned before, we know there is a relationship between DCM and low taurine levels, but DCM can also be caused by various factors including genetics, age and weight.

A common issue reported to the FDA included low taurine levels in the blood of dogs with DCM. Dogs are able to make enough taurine themselves, as long as sulfur amino acids (methionine and cysteine) are sufficiently provided in the diet. Taurine supplementation is also an effective way to reverse DCM.

Have Researchers Confirmed a Link Between Grain-Free Dog Food and Cardiomyopathy?

Many studies have been published since the FDA’s initial statement, investigating the effects of grain-free diets on taurine status in healthy dogs. These studies have suggested that grain-free diets do not affect taurine status negatively. Animals have nutrient requirements, not requirements for specific ingredients. If there are imbalances in the diet, the final nutrient composition of the diet should be addressed, not the ingredients selected to provide those nutrients. Ensuring the proper concentrations of sulfur amino acids is extremely important. It is essential that there be enough for taurine synthesis to meet the demands of dogs. Other dietary factors like total dietary fibre as well as animal factors like breed, size, and health status are also important to consider when a nutrient deficiency-related DCM is of concern.

The FDA recently released an update regarding grain-free dog food and cardiomyopathy. The FDA partnered with the veterinary laboratory network to examine 150 dogs diagnosed with DCM to identify factors causing their DCM. Their results show that DCM is a multifactorial issue with many potential variables. Dog breed, age, weight, gastrointestinal disease, infection and more are all factors. The FDA also stated that for dogs who had experienced a partial or full recovery, diet change was not necessarily responsible. Nearly all dogs were treated with taurine, pharmaceutical drugs and other drugs or supplements.

More research is still needed, but the current results show that DCM is caused by many variables alongside the choice of diet. Currently, there is no certain association between grain-free diets and DCM in dogs.

Studies mentioned:

Donadelli, R. A., Pezzali, J. G., Oba, P. M., Swanson, K. S., Coon, C., Varney, J., … Shoveller, A. K. (2020). A commercial grain-free diet does not decrease plasma amino acids and taurine status but increases bile acid excretion when fed to Labrador Retrievers. Translational Animal Science, 4(3). https://doi.org/10.1093/tas/txaa141

Mansilla, W. D., Marinangeli, C. P. F., Ekenstedt, K. J., Larsen, J. A., Aldrich, G., Columbus, D. A., … Shoveller, A. K. (2019, March 1). Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: Addressing the knowledge gaps before establishing causation. Journal of Animal Science. Oxford University Press. https://doi.org/10.1093/jas/sky488

McCauley, S. R., Clark, S. D., Quest, B. W., Streeter, R. M., & Oxford, E. M. (2020). Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. Journal of Animal Science, 98(6), 1–20. https://doi.org/10.1093/jas/skaa155

Pezzali, J. G., Acuff, H. L., Henry, W., Alexander, C., Swanson, K. S., & Aldrich, C. G. (2020). Effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Journal of Animal Science, 98(2), 1–9. https://doi.org/10.1093/jas/skaa010

Pezzali, J. G., & Aldrich, C. G. (2019). Effect of ancient grains and grain-free carbohydrate sources on extrusion parameters and nutrient utilization by dogs. Journal of Animal Science, 97(9), 3758–3767. https://doi.org/10.1093/jas/skz237