Grain Free Foods and Heart Disease: What You Need to Know



By Dr. Sarah Wallace


You are the champion of your pet's wellness care and that means nutrition is on your mind. With so many options and so much information out there, it can be tough to know what is best to feed your fuzzy family member. There have been recent links between grain-free pet foods and a condition called DCM, or dilated cardiomyopathy. This new information has fostered some fear and confusion with pet parents. Let's talk about what we do know and what you can do to rest easy.


Dilated cardiomyopathy is a condition in which the walls of the heart become thin and weak, resulting in decreased ability of the heart to pump blood through the pet’s body. 

A brief history of DCM emerges from a single amino acid - taurine. Taurine is specifically needed for healthy heart function, retinal function, reproductive health, and as a component of bile acids. The cat body is unable to build taurine if it is not consumed in the diet. Since taurine is almost exclusively found in meat sources, this means cats must eat meat to survive and are therefore, obligate carnivores. Without consuming taurine, cats can develop dilated cardiomyopathy. In contrast, dogs do have the ability to build taurine in their body if it is not eaten in the diet. So diet-associated DCM occurs far less frequently in dogs than in cats.  There are some dog breeds who are genetically predisposed to developing DCM. In 2016, veterinarians began diagnosing DCM in dogs that aren't the usual breeds we expect to develop DCM. After a closer look, studies began to show that these dogs were often fed a grain-free or boutique-type diet.  Grain-free diets have been a fad for a number of years now, however, there is no scientific evidence showing that grain-free diets are any better than diets containing grains. Now that these studies on grain-free diets and heart disease have surfaced, it's important to understand what we do and do not know. 

“Grain-free” diets in general do not cause heart disease. We are currently investigating the possibility that certain ingredients used more commonly and in greater quantities in grain-free diet may have a role to play in the development of DCM in dogs. Foods that contain high-levels of peas, lentils, other legume seeds, and/or potatoes have been found to negatively affect taurine levels. These ingredients have been identified by the FDA as potential risk factors, and since they are frequently found in foods that are promoted as “grain-free”, the association was created. Since associations do not prove causation, this question is still being investigated. 

For dogs currently eating a grain-free diet, but not showing any signs of heart disease - such as exercise intolerance, weakness or collapse, changing the diet to one that contains grains is the simplest and most conservative action until more conclusive research relating to this emerging pattern is discerned.  Many pet parents look to grain-free or gluten-free diets when they suspect a food allergy in their dogs or cats, but the reality is that the most common food allergens stem from protein sources, such as chicken, beef, and fish. Food allergy symptoms may include itchiness, skin infections, and gastrointestinal upset. Home-cooked meals or “novel protein” diets are typically best to pursue for allergy trials instead of resorting to “grain-free”. If your pet is currently eating a grain-free diet and you are reluctant to make the transition away, we advise consulting your veterinarian about pursuing a cardiac ultrasound (echocardiogram) to see if your dog has evidence of cardiomyopathy. If your dog is found to be affected, even without showing any clinical signs, it’s recommended to change the diet to a grain-based commercial diet. If you have a dog that is “at risk” for taurine deficiency (including American Cocker Spaniels, Golden Retrievers, Newfoundlands, and Dalmatians) and is eating an implicated diet, we advise having their blood taurine levels checked. While there is still research to be done, for now, we recommend checking individual diets and avoiding formulas that include peas, lentils, and potatoes (including sweet potatoes) together, as these ingredients are possibly associated with the condition. Some diets may include a few or one of these ingredients; if one of the ingredients is listed without the other two, it is less of a concern especially if appears lower on the ingredient list.

While these studies and the accompanying FDA warning can appear alarming, the truth in what we know right now is that there is no direct evidence showing that a specific dog food type, brand, or even ingredient is exclusively responsible for taurine-deficiency DCM in dogs. Because these ingredients identified by the FDA report have not yet been comprehensively studied, we cannot conclude any underlying dietary cause of this condition. If you have any questions regarding your pet’s specific dietary needs or individual care, please do not hesitate to reach out to Fuzzy. We are here to keep your pet heart-happy!

-- with Contributions by Lulu Samuel