Key Takeaways
- The FDA identified a possible link between grain-free diets and DCM in dogs starting in 2018, but a definitive causal mechanism has not been established.
- Many affected dogs were eating diets high in legumes, lentils, or potatoes as primary ingredients — not necessarily just the absence of grains.
- Taurine deficiency appears to be a factor in some cases, though not all DCM-affected dogs had low taurine levels.
- Certain breeds already prone to DCM genetically may be harder to separate from diet-related cases in the data.
- Consult your veterinarian before changing your dog's diet, especially if your dog is a large or giant breed.
Dilated Cardiomyopathy (DCM)
Dilated cardiomyopathy is a disease of the heart muscle in which the heart's chambers enlarge and the walls weaken, reducing its ability to pump blood efficiently. In dogs, it can lead to congestive heart failure, irregular heartbeats, and in severe cases, sudden death. It has historically been most common in large and giant breeds such as Great Danes, Doberman Pinschers, and Irish Wolfhounds.
DCM can have both genetic and acquired causes. The FDA investigation beginning in 2018 focused on a potentially diet-associated, non-hereditary form appearing in breeds not traditionally predisposed to the condition.
How the FDA Investigation Began
In July 2018, the U.S. Food and Drug Administration (FDA) issued an alert describing an apparent increase in DCM diagnoses among dogs eating certain grain-free diets. What made the pattern unusual was that many of the affected animals were breeds not historically prone to the condition — including Golden Retrievers, Labrador Retrievers, and mixed-breed dogs.
The FDA collected several hundred case reports submitted by veterinary cardiologists and general practitioners. While these numbers were not large relative to the overall dog population, the consistent dietary thread — foods listing peas, lentils, chickpeas, or potatoes as primary ingredients — raised enough concern to warrant a formal investigation. The agency communicated that it was not recommending that pet owners immediately abandon grain-free diets, but that veterinarians and owners should be aware of the emerging signal.
Investigation Status Remains Open
As of the FDA's most recent publicly available updates, the investigation into diet-associated DCM has not been formally closed, and no specific food products have been recalled solely on this basis. The agency continues to work with veterinary researchers and academic institutions to better understand the relationship. Owners should monitor the FDA's Canine Heart Disease page for updates.
What the Evidence Does and Doesn't Show
The critical point for any dog owner to understand is that an association is not the same as a proven cause. The FDA data showed a correlation: dogs eating certain diet types appeared more frequently in DCM reports. However, correlation alone does not identify a mechanism, rule out confounding variables, or confirm that the diet caused the disease.
Researchers have proposed several hypotheses. One focuses on taurine — an amino acid essential for normal heart function. Some grain-free diets may be lower in taurine precursors, or high legume content may inhibit taurine absorption or synthesis. A second hypothesis suggests that some diets are simply poorly formulated regardless of whether they contain grains. A third acknowledges that genetic predisposition in certain lines of popular breeds (such as Golden Retrievers) may have been underestimated.
524
DCM cases reported to the FDA (2014–2019)
The FDA's 2019 update cited 524 reports of canine DCM potentially linked to diet, with 119 deaths reported among those cases.
~56%
Reported cases involving Golden Retrievers
Golden Retrievers represented a disproportionately large share of diet-associated DCM reports, despite not being a classically predisposed breed, according to FDA case data.
91%
Cases linked to grain-free labeled foods
The FDA's 2019 report noted that approximately 91% of the diet-associated DCM cases involved foods marketed as grain-free.
Importantly, not all DCM-affected dogs were taurine-deficient, and not all dogs eating the implicated diets developed DCM. This inconsistency makes a simple single-cause explanation unlikely.
The Role of Legumes and Diet Formulation
The emerging focus of researchers is less on the absence of grains and more on what replaces them. When grains like rice, oats, or barley are removed from a diet, manufacturers often substitute high volumes of peas, lentils, or potatoes to maintain carbohydrate content and binding properties. These ingredients are not inherently harmful, but their nutritional interactions at high inclusion rates — particularly their effects on amino acid metabolism — are not yet fully characterized in dogs.
This is a meaningful distinction for owners reading labels. A food labeled grain-free is not automatically nutritionally deficient, nor is a grain-inclusive food automatically superior. What matters is the overall nutrient profile, ingredient quality, and whether the diet meets standards established by the Association of American Feed Control Officials (AAFCO). Understanding how to evaluate those details is covered more thoroughly in our guide on reading a dog food ingredient list.
Look Beyond the 'Grain-Free' Label
When evaluating any dog food, check whether peas, lentils, or potatoes appear in the first five ingredients. A diet's safety is determined by its complete nutrient profile and manufacturing quality — not simply whether it contains or excludes grains. Ask your veterinarian to help you assess specific formulations if you're uncertain.
What Dog Owners Should Actually Do
Uncertainty in the science does not mean inaction. There are practical, evidence-informed steps owners can take while researchers continue to clarify the picture.
- Talk to your vet: If your dog is eating a diet heavy in legumes or potatoes as primary ingredients, raise it at your next appointment. Breeds such as Golden Retrievers, Dobermans, and Boxers may warrant cardiac monitoring.
- Watch for early symptoms: Reduced stamina, labored breathing, and fainting are signs that warrant prompt veterinary evaluation. Early detection significantly improves outcomes.
- Evaluate diet holistically: Whether your dog eats grain-free or grain-inclusive food, the priority is a complete and balanced formulation verified by feeding trials, not just nutrient analysis.
- Don't self-supplement: Adding taurine without veterinary guidance is not recommended. Excess supplementation carries its own risks, and the root cause of DCM in any individual dog requires diagnosis before treatment.
Nutritional needs also shift across a dog's life — factors like life stage, size, and activity level all influence what constitutes an appropriate diet. Our article on pet nutrition from puppyhood to senior years offers a broader framework for thinking about those changes. If you notice signs that your dog's current diet may not be meeting their needs, the guidance in our piece on signs a pet's diet may not be meeting their nutritional needs can help you identify what to discuss with your veterinarian.
This article is for general informational purposes only and does not constitute veterinary or medical advice. Always consult a licensed veterinarian for guidance specific to your dog's health and diet.