The short answer
The U.S. Food and Drug Administration has not established that grain-free food causes heart disease in dogs. It has investigated reports of dilated cardiomyopathy (DCM) since July 2018, says the link between diet and DCM is a complex scientific issue that may involve multiple factors, and said in December 2022 that case reports alone do not establish cause. A 2023 University of Guelph trial of 28 Siberian Huskies found no heart changes on diets with up to 45% pulses over 20 weeks; the trial was small and short, and a pet food manufacturer paid for it. We found no CVMA statement on the question. If your dog eats grain-free food, tell your vet and do not switch food on your own. Learn the signs: low energy, cough, trouble breathing and collapse.
PawTrace is not a vet. This guide shares what we found in the sources listed below; ask your vet about your own dog.
Quick highlights
- The FDA (U.S.) has not established that grain-free food causes heart disease in dogs.
- A 2023 University of Guelph trial of 28 Siberian Huskies found no heart changes on diets with up to 45% pulses; the trial was small and a pet food manufacturer paid for it.
- We found no CVMA statement on grain-free food and DCM.
- If your dog eats grain-free food, tell your vet and do not switch food on your own.
Key takeaways
- DCM is a disease of the heart muscle. It has genetic forms, notably in Doberman Pinschers and Boxers, and other causes including taurine deficiency (Merck Veterinary Manual (U.S.)).
- FDA (U.S.) began investigating in July 2018 after reports of DCM in dogs eating foods, many labelled grain-free, with peas, lentils, other pulses or potatoes among the main ingredients. FDA calls the association complex and says reports alone do not establish cause.
- FDA has issued no further public updates since December 23 2022 and says it will wait for meaningful new scientific information.
- Merck (U.S.) says it is likely not that simple: dogs have developed diet-linked DCM on diets that do not fit the pattern, and not every diet that fits the pattern has been linked.
- Canadian evidence is thin. We found no CVMA position statement, no CFIA or Health Canada page on DCM, and no statement from the other Canadian vet colleges. The Ontario Veterinary College and University of Guelph have published a 2023 feeding trial and have experts who speak on the topic.
- Do not change your dog’s food in a panic. FDA urges owners to work with their vets, who may consult a board-certified veterinary nutritionist, before making a diet change.
- See your vet promptly for low energy, cough, trouble breathing or collapse, and go to an emergency clinic if signs are severe and your vet is not available.
What DCM is
The Merck Veterinary Manual (U.S.) describes DCM as a progressive loss of heart muscle cells and function, with reduced pumping strength. It is most common in dogs and especially in certain breeds, and typically affects middle-aged to older male dogs. Merck lists causes as chemical, viral, nutritional (taurine deficiency), genetic (in Doberman Pinschers and Boxers) or idiopathic, which means no cause is found. It says the disease has a protracted phase without signs, and signs show for a relatively short time. Echocardiography, an ultrasound of the heart, is the best test to diagnose it.
Merck lists exercise intolerance, weakness and fainting as signs of too little blood reaching the organs, and fluid in the lungs or abdomen as signs of blood backing up. Merck’s DCM page adds that fluid in the abdomen, fast breathing, trouble breathing or cough may appear, depending on the type of heart failure. None of these signs proves DCM; they call for a vet exam.
What the FDA found, and what it did not (U.S.)
FDA’s page was last updated December 23 2022. It covers a report period from January 1 2014 to April 30 2019. The table sets out what FDA says and the limits it states.
| Item | What FDA says | Source |
|---|---|---|
| Reports | 524 reports of DCM (515 canine, 9 feline) between January 1 2014 and April 30 2019. For dogs, 560 animals affected and 119 deaths. Most reports came after FDA notified the public in July 2018. | FDA (U.S.) |
| Foods in the reports | More than 90% of reported products were grain-free and 93% contained peas and/or lentils. A far smaller share contained potatoes. | FDA (U.S.) |
| Nutrient testing | FDA testing found average protein, fat, taurine, cystine and methionine content, on a dry matter basis, similar for grain-free and grain-containing products. | FDA (U.S.) |
| Breeds | Many reports involved breeds not previously known to have a genetic predisposition. FDA observed a reporting bias for breeds such as Golden Retrievers, because breed-specific social media groups urged owners and vets to report. | FDA (U.S.) |
| Cause | FDA believes the association between diet and DCM is a complex scientific issue that may involve multiple factors. On December 23 2022 it said adverse event numbers by themselves do not supply sufficient data to establish a causal relationship with reported products. | FDA (U.S.) |
| What next | FDA does not intend to release further public updates until there is meaningful new scientific information to share. | FDA (U.S.) |
FDA also published a graph of the brands named in the reports. We do not name any food here. A brand named in a report is not a finding on that product, and FDA says the numbers cannot show cause.
What Merck says: diet-linked DCM is not a simple story (U.S.)
The professional edition of the Merck Veterinary Manual (reviewed August 2025) has a section on diet-associated DCM. It reports the following.
- Many suspect diets had high proportions of pulses (peas, chickpeas, lentils, dried beans) and also potatoes and sweet potatoes, but not soybeans.
- The situation is likely not that simple. Not all diets that fit the description have been linked to non-hereditary DCM, and dogs have developed it on diets that do not fit.
- Other factors that might be associated include myocarditis, hyperthyroidism and nutritional imbalances such as low taurine or high insoluble fibre.
- NH-DCM has been reported in a wide range of breeds, including toy breeds. One analysis suggested sampling bias was possible, because dogs eating grain-free or high-lentil diets were more likely to be reported.
- Dogs switched from grain-free to traditional diets, alongside heart treatment, have shown significant improvement in heart scans and clinical outcomes. In some reported cases, a longer time on a grain-free diet appeared linked to a worse outlook. Merck says these findings are suggestive but not clear enough to prove cause and effect.
- Some sources have suggested it might be prudent to avoid diets that list pulses in the top 10 ingredients or that contain multiple pulses. Merck reports that as a suggestion, not a rule.
What Canadian sources say
| Source | What it says | Date |
|---|---|---|
| University of Guelph and Ontario Veterinary College, expert alert | Lists three Guelph experts available to speak on the topic: an animal nutrition professor, a veterinarian and PhD candidate in the OVC’s population medicine department, and a veterinary cardiology resident. The page reports that an FDA warning linked grain-free diets to DCM, a potentially life-threatening heart disease, and notes that FDA listed brands. It gives no advice to owners. | Undated page (URL shows July 2019) |
| University of Guelph, “Peas of Mind” trial news | A randomized controlled trial of 28 Siberian Huskies fed one of four diets with 0, 15, 30 or 45% whole pulses for 20 weeks. Echocardiograms and heart biomarkers showed no signs of heart problems on any diet, including up to 45% pulses and no grains. Huskies were chosen because they are not genetically at risk. The peer-reviewed paper is Singh and colleagues, The Journal of Nutrition (2023). Funding: a pet food manufacturer paid for the trial and processed the diets, three of the paper’s eleven authors work for that company, and the lead researcher holds a university research chair named for it. The university says the company did not influence the findings or conclusions. | Posted April 17 2023; updated February 5 2026; paper published May 2023 |
| Canadian Veterinary Medical Association, position statements | We found no position statement on grain-free diets or DCM. The only pet food statement listed is on raw meat-based products. | Checked October 23 2026 |
| Canadian Food Inspection Agency | We found no CFIA or Health Canada page on DCM. CFIA says pet food is not a comprehensively regulated commodity in Canada and that its oversight is limited to import and export requirements. | Page modified December 13 2022 |
| Other Canadian vet colleges (Western, Atlantic, Calgary, Montréal) | We found no owner statement on grain-free diets and DCM from these colleges. | Searched October 23 2026 |
Read the Guelph trial with its limits in mind. The numbers say 28 dogs, one breed that is not at risk, and 20 weeks. Those are facts from the university’s own summary; our reading is that a trial this size and length cannot rule out a rare or slow effect, and that it tests pulses, not every ingredient in every food. The researcher who led it, in the same article, said ensuring foods exceed minimum nutrient requirements matters, and another researcher said some dogs might be healthy while others have specific health conditions.
If you live in Ontario, the University of Guelph posted a study in June 2024 seeking healthy adult small dogs and male large dogs that had eaten grain-free kibble for at least six months, offering a free echocardiogram and bloodwork (posting). We do not know whether it is still open; check the page.
Breeds with a genetic DCM risk
Genetic DCM exists whatever the dog eats, so a DCM diagnosis in one of these breeds does not point to the food. Ask your vet whether screening suits your dog.
| Breed | What the source says | Source |
|---|---|---|
| Doberman Pinscher | Genetic DCM. Merck says premature ventricular contractions on a routine ECG in a Doberman are highly suggestive of DCM, and that treatment may be indicated in Dobermans with DCM before heart failure begins. FDA lists it as a recognized genetic case. | Merck Veterinary Manual (U.S.); FDA (U.S.) |
| Boxer | Genetic (Merck). Merck separately lists arrhythmic cardiomyopathy in Boxers among the important heart diseases in dogs. | Merck Veterinary Manual (U.S.); Merck, heart disease in dogs |
| Great Dane, Irish Wolfhound | Recognized as genetic in large and giant breeds (FDA). Merck lists both as particularly at risk and says atrial fibrillation is the typical rhythm problem in giant breeds. | FDA (U.S.); Merck Veterinary Manual (U.S.) |
| German Shepherd Dog, Scottish Deerhound, Newfoundland, Saint Bernard, Labrador Retriever | Listed by Merck as particularly at risk of DCM. | Merck Veterinary Manual (U.S.) |
| Cocker Spaniel | FDA says DCM is also seen in Cocker Spaniels associated with taurine deficiency. | FDA (U.S.) |
| Golden Retriever | FDA says past research suggests Golden Retrievers may be genetically predisposed to taurine deficiency, and that many Golden Retriever DCM cases are taurine-deficient. FDA also notes reporting bias for this breed. | FDA (U.S.) |
Small breeds are not exempt. FDA says DCM is believed to be less common in small and medium breeds, and Merck says non-hereditary DCM has been reported in toy breeds.
What to do: practical steps
- Tell your vet what your dog eats. FDA says your vet may ask for a thorough diet history, including all foods and treats. Keep a photo of the food label and treat packaging.
- Do not switch food alone. FDA urges owners to work with their vets, who may consult a board-certified veterinary nutritionist, before making diet changes. If your dog moved to grain-free food for itchy skin, tell your vet that too; our guide to itchy dogs and allergies explains why a food change is not a test.
- Know the signs. FDA lists decreased energy, cough, difficulty breathing and episodes of collapse. A University of Wisconsin cardiologist’s page (U.S.; it cites 2019 FDA data) lists difficulty breathing, cough, irregular heart rhythms, fainting and fluid in the abdomen.
- Ask which tests suit your dog. Merck says echocardiography is the best test for DCM. The Wisconsin page recommends blood taurine testing for dogs suspected of having or diagnosed with DCM that eat grain-free, vegetarian, vegan or home-prepared diets. For apparently healthy dogs on boutique, exotic, grain-free, home-cooked, vegetarian or raw diets, it says owners who want screening can ask their vet for an NT-proBNP blood test. That page is undated, cites FDA updates only to June 2019 and says its recommendations may change over time, so ask your vet what applies now.
- If possible diet-associated DCM is diagnosed, the Wisconsin page recommends changing to a diet from a well-established manufacturer with standard ingredients, taurine supplements for dogs with low blood taurine, and heart medicines for dogs with severe signs. Your vet decides.
- Seek urgent care for severe signs. FDA says to seek emergency veterinary care if signs are severe and your vet is not available. See our guide to emergency signs.
For how food is regulated and how to read a label, see our guides on reading a dog food label in Canada and choosing dog food types. To check recalls, use the Government of Canada’s Recalls and safety alerts site, where pet food recalls are posted as Health Canada consumer product recalls.
Myth vs fact
| Myth | Fact |
|---|---|
| FDA proved grain-free food causes heart disease. | FDA says the association is complex and may involve multiple factors, and that reports alone cannot establish cause. Merck (U.S.) says the findings are suggestive but not clear enough to prove cause and effect. |
| Only dogs on grain-free food get DCM. | Merck (U.S.) says dogs can develop diet-linked DCM on diets that do not fit the pattern, and DCM has genetic and other causes. FDA says many affected dogs are from breeds with no known predisposition, and that DCM is also recognized as genetic. |
| The missing grain is the problem. | FDA reports that more than 90% of foods in the reports were grain-free and 93% had peas and/or lentils, and its testing found similar average nutrient content in grain-free and grain-containing foods. FDA’s questions and answers page (U.S.; updated August 19 2024) says it has received reports linked to both grain-free and grain-containing diets, most with pulses high in the ingredient list, and that pulses have been used in pet foods for many years with no evidence that they are inherently dangerous. Cause is not established. |
| Grain-free food is safer for dogs with allergies. | Merck (U.S.) lists beef, dairy products, chicken, wheat and lamb as the most common food allergens in dogs. Food allergy is confirmed by a diet trial with your vet, not by removing grain. |
| If I am worried, I should switch food today. | FDA urges owners to work with their vets before making diet changes. Merck says dogs switched from grain-free diets improved alongside heart treatment, which is a reason to involve your vet, not to guess. |
Frequently asked questions
Should I stop feeding my dog grain-free food?
Ask your vet, who knows your dog’s health and breed. FDA (U.S.) urges owners to work with their vets, who may consult a board-certified veterinary nutritionist, before making diet changes. No source we found tells owners of healthy dogs to switch on their own.
Does Canada’s government say grain-free food causes DCM?
We found no Health Canada or CFIA page on DCM. CFIA says pet food is not a comprehensively regulated commodity in Canada. The FDA investigation is a U.S. investigation, and its page says reports do not establish cause.
What signs of heart disease should I watch for?
FDA (U.S.) lists decreased energy, cough, difficulty breathing and collapse. Merck (U.S.) lists exercise intolerance, weakness and fainting, and fluid in the lungs or abdomen. Contact your vet as soon as possible, or an emergency clinic if signs are severe.
Can small dogs get DCM?
Yes. Merck (U.S.) says non-hereditary DCM has been reported in a wide range of breeds, including toy breeds, and that some dogs, small breeds or dogs on grain-free diets among them, can have taurine-responsive DCM. FDA says DCM is believed to be less common in small and medium breeds.
What is taurine, and should I add it to my dog’s food?
Taurine is an amino acid. FDA notes it is generally not considered essential for dogs because they can make it, but says it is still studying whether taurine metabolism plays a role. Merck (U.S.) says some dogs with DCM are taurine-responsive. Do not add supplements without your vet; the Wisconsin cardiologist’s page recommends taurine supplements for dogs whose blood taurine tests low, with the testing arranged through your vet.
Is there a Canadian test or registry for diet-linked DCM?
We found no Canadian reporting system for diet-linked DCM. FDA runs a Safety Reporting Portal for U.S. vets, and its page tells vets to report well-documented cases there. Ask your vet whether a case in your dog warrants a report.
Next step
If your dog eats grain-free food and you want a heart check, or your dog shows any sign listed above, call your vet. You can search for a clinic on our find a vet page. For other dog services near you, see our dog services directory.
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Sources
All links were checked on October 23 2026. Sources marked (U.S.) are not Canadian.
- U.S. Food and Drug Administration (U.S.): FDA investigation into potential link between certain diets and canine dilated cardiomyopathy (last updated December 23 2022)
- U.S. Food and Drug Administration (U.S.): Questions and answers, FDA’s work on potential causes of non-hereditary DCM in dogs (content current as of August 19 2024)
- Merck Veterinary Manual (U.S.), professional version: Dilated cardiomyopathy in dogs and cats (full review January 2023, updated September 2024)
- Merck Veterinary Manual (U.S.), professional version: Cutaneous food allergy in animals, section on diet-associated dilated cardiomyopathy (updated August 2025)
- Merck Veterinary Manual (U.S.): Heart disease in dogs (last updated September 2024)
- University of Guelph: Experts alert, potential risks of grain-free pet diets (undated page, URL dated July 2019)
- University of Guelph: Peas of mind, pulse ingredients in dog food not linked to heart problems, says new U of G research (April 17 2023, updated February 5 2026)
- Singh P, Banton S, Raheb S, et al. 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 153(5):1461-1475 (2023). Three authors are employees of the funding pet food manufacturer.
- University of Guelph, Department of Animal Biosciences: canine DCM study listing (submitted June 10 2024)
- University of Wisconsin School of Veterinary Medicine (U.S.): Diet-associated cardiac disease in dogs, resources and recommendations (undated page)
- Canadian Veterinary Medical Association: Position statements
- Canadian Food Inspection Agency: Regulatory oversight of pet food, treats and chews in Canada (modified December 13 2022)
- Government of Canada: Recalls and safety alerts
General information only. This guide is not veterinary advice and cannot diagnose your dog. Ask your vet to review your dog’s diet and heart health. Written by the PawTrace Team.
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