There’s a lot of confusion around grain-free dog food and its potential link to heart disease (DCM). This article breaks down the facts and current research.
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FDA investigated reports of heart disease possibly linked to grain-free diets.
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No definitive cause was found—many factors are likely involved.
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Grain-free isn’t always better; not all dogs need to avoid grains.
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Veterinary guidance is essential for choosing the right diet.
We unpack the science, share expert insights, and explain how to make the best choice for your dog’s health. Keep reading to get the full picture.
A heart disease diagnosis raises many questions for pet parents, including what to feed their dog. A dog’s diet is the most important element of his overall health care, and thus, it’s an important decision.
As a result, many pet parents have become increasingly interested in grain-free diets and grain-free dog food. But, as a result of this interest, many veterinarians and pet owners are worried about the link between grain-free diets and heart disease, namely dilated cardiomyopathy (DCM).
This post is an educational guide covering what heart disease is, what causes it, how it presents, and what nutritional factors veterinarians typically consider.
What is heart disease in dogs?
Heart disease a broad term covering several conditions that affect the heart’s ability to pump blood efficiently. It tends to develop gradually, often over years. The two most common forms of heart disease are degenerative mitral valve disease (MVD) and dilated cardiomyopathy (DCM). While some dogs are genetically predisposed, the condition can affect any breed or age, and early detection is central to long-term management.
What causes heart disease in dogs?
There are several potential causes of heart disease in dogs, including:
- Degenerative Valve Disease: The most common cause of heart disease in dogs, this condition occurs when heart valves gradually thicken and fail to close properly, allowing blood to leak backward with each heartbeat.
- Dilated Cardiomyopathy: DCM is a disease of the heart muscle. The disease causes arrhythmias (where the heart or parts of the heart beat weakly/abnormal heart rhythm). As the heart muscle function works harder to do its job, it becomes enlarged. It’s quite common, and in fact, DCM is the second most common canine heart disease.
- Congenital Heart Defects: Some dogs are born with structural abnormalities that disrupt normal blood flow from birth. Some dogs live normally with mild defects, while others require early surgical intervention.
- Heartworm: Transmitted through mosquito bites, heartworm infection causes lasting damage to the heart and pulmonary arteries, leading to inflammation, scarring, and increased cardiac workload. It is largely preventable with consistent veterinary-recommended preventatives.
- Arrhythmias and Electrical Dysfunction: Some dogs develop abnormal heart rhythms that impair pumping efficiency even without structural damage. If left unmanaged, it can accelerate cardiac decline.
What are some common signs of heart disease in dogs?
Coughing or Labored Breathing
A persistent cough may signal fluid buildup in or around the lungs as the heart weakens. You may also notice faster or more labored breathing than usual.
Exercise Intolerance
A dog who tires quickly, lags on walks, or loses interest in activities they once loved may not be getting enough oxygen-rich blood to their muscles — a hallmark of reduced heart function.
Abdominal Swelling
Poor circulation can cause fluid to accumulate in the abdomen, making the belly appear bloated or distended even without much food intake.
Irregular Heartbeat or Fainting
Abnormal heart rhythms can cause sudden episodes of weakness, collapse, or brief fainting.
Unexplained Weight Loss or Reduced Appetite
Heart disease puts significant stress on the body, leading to muscle loss and weight drop even without dietary changes. A reduced interest in food often compounds the problem.
If your dog is showing any of these signs, do not wait to see if they improve on their own. These symptoms should prompt an immediate consultation with a veterinarian.
Ingredients and dietary factors to be mindful of
Veterinarians commonly address the following nutritional factors and dietary considerations for dogs with heart conditions.
Protein quality and sources
Dogs with heart disease need high-quality, digestible protein from whole meat sources to combat muscle wasting. Vague by-products and fillers are best avoided in favor of named ingredients like chicken, beef, or salmon.
Omega-3 fatty acids
EPA and DHA from fish oil and algae oil in heart-healthy dog food may help reduce inflammation, support heart rhythm, and slow muscle loss. Many veterinary cardiologists recommend fish oil supplementation even alongside a cardiac diet for dogs.
Taurine and L-carnitine
One of the first causes suspected in diet-associated DCM was taurine deficiency. Taurine supplements are often used in conjunction with carnitine (an amino acid) to treat heart disease like DCM. (Other medications used include pimobendan, diuretics, ACE inhibitors, and cardiac glycocides.)
Sodium levels and processed ingredients
Excess sodium levels cause fluid retention, adding strain to a weakened heart. Salty treats, processed human foods, and high-sodium commercial kibbles should be avoided. Make sure your pet is on a low-sodium diet.
Grain-free diets
In one study conducted by the College of Veterinary Medicine at North Carolina State University, dogs fed a grain-free diet showed that part of their heart was consistently larger than dogs fed a grain-based diet. A potential link between grain-free diets high in peas, lentils, or legumes and increased DCM risk has prompted many veterinary cardiologists to advise caution. Dogs on these formulas are often transitioned to more traditional diets or cardiac dog food as a precaution.
How nutrition fits into your dog’s lifelong wellness
As a loving pet parent, you want to keep your best furry friends safe from harm. Heart disease in dogs is a complex, progressive condition with multiple forms and causes; recognizing signs early may lead to better outcomes. Nutrition is a meaningful way to support a dog’s overall health and comfort at every stage of life.
Remember: a veterinarian is the essential partner in both understanding the condition and determining an appropriate dietary approach for the individual dog.
Citations
Bakke, Anne Marie, Joshua Wood, Carina Salt, David Allaway, Matt Gilham, Gail Kuhlman, Tiffany Bierer, Richard Butterwick, and Ciaran O’Flynn. 2022. “Responses in Randomised Groups of Healthy, Adult Labrador Retrievers Fed Grain-Free Diets with High Legume Inclusion for 30 Days Display Commonalities with Dogs with Suspected Dilated Cardiomyopathy.” BMC Veterinary Research 18 (1). https://doi.org/10.1186/s12917-022-03264-x.
Singh, Pawanpreet, Sydney Banton, Shari Raheb, James R. Templeman, Jennifer Saunders-Blades, Darcia Kostiuk, Janelle Kelly, et al. 2023. “The Pulse of It: Dietary Inclusion of up to 45% Whole Pulse Ingredients with Chicken Meal and Pea Starch in a Complete and Balanced Diet Does Not Affect Cardiac Function, Fasted Sulfur Amino Acid Status, or Other Gross Measures of Health in Adult Dogs.” The Journal of Nutrition, March. https://doi.org/10.1016/j.tjnut.2023.03.027.
Fischer, Kara E, John E Rush, and Lisa M Freeman. 2023. “Pit Bull–Type Breeds with Dilated Cardiomyopathy Eating Nontraditional Diets Improve after Diet Change (2015–2022).” Javma-Journal of the American Veterinary Medical Association, April, 1–9. https://doi.org/10.2460/javma.23.01.0025.
Bakke, Anne Marie, Joshua Wood, Carina Salt, David Allaway, Matt Gilham, Gail Kuhlman, Tiffany Bierer, Richard Butterwick, and Ciaran O’Flynn. 2022. “Responses in Randomised Groups of Healthy, Adult Labrador Retrievers Fed Grain-Free Diets with High Legume Inclusion for 30 Days Display Commonalities with Dogs with Suspected Dilated Cardiomyopathy.” BMC Veterinary Research 18 (1). https://doi.org/10.1186/s12917-022-03264-x.
Adin, Darcy, Teresa C. DeFrancesco, Bruce Keene, Sandra Tou, Kathryn Meurs, Clarke Atkins, Brent Aona, Kari Kurtz, Lara Barron, and Korinn Saker. 2019. “Echocardiographic Phenotype of Canine Dilated Cardiomyopathy Differs Based on Diet Type.” Journal of Veterinary Cardiology 21 (February): 1–9. https://doi.org/10.1016/j.jvc.2018.11.002.
Smith, Caren E., Laurence D. Parnell, Chao-Qiang Lai, John E. Rush, and Lisa M. Freeman. 2021. “Investigation of Diets Associated with Dilated Cardiomyopathy in Dogs Using Foodomics Analysis.” Scientific Reports 11 (August). https://doi.org/10.1038/s41598-021-94464-2.
FAQ
What are the stages of heart disease in dogs?
There are four stages of heart disease in dogs: Stages A-D. Stage A dogs are at risk. They don’t show signs of poor heart health but are genetically predisposed to it. Dogs in Stage B have a detectable heart abnormality, like a murmur, but show no outward signs of heart failure. This stage is divided into two subcategories: B1, where the heart has not yet changed in size, and B2, where measurable enlargement has begun. Stage C dogs have structural heart disease and show clinical signs of heart failure. Medical management at this stage is more intensive. Stage D represents end-stage heart disease in which the dog’s symptoms no longer respond ot treatment. The focus at this stage shifts toward comfort and quality of life, with veterinarians exploring advanced or combination treatments to manage symptoms as effectively as possible.
What has the FDA found about grain-free dog food?
In 2018, acting on the advice of veterinary nutritionists, the Food and Drug Administration (FDA) initiated an investigation into a link between canine dilated cardiomyopathy and certain diets. The investigation gathered reports from January 2018 through April 2019. The reports indicated 553 dogs had developed DCM, as compared to previous years in which only three were reported. IThe breed breakdown was the following:
- 95 Golden Retrievers
- 62 mixed-breed dogs
- 47 Labrador Retrievers
- 25 Great Danes
- 50 cases involving additional breeds
Moreover, the FDA found that 16 pet food companies had ten or more cases of DCM associated with their foods. Of those foods, more than 90% were grain-free, and 93% contained peas or lentils. Some also contained potatoes.
All grain-free diets had the same average percentages of fat, protein, taurine, and taurine precursors as grain-based diets. A 2021 study out of Tufts University found that the inclusion of peas represented the greatest difference between the diets.
This content is for informational use only and does not replace professional nutrition and/or medical advice, diagnosis, or treatment. It is not a substitute for and should not be relied upon for specific nutrition and/or medical recommendations. Please talk with your veterinarian about any questions or concerns.
