For a while, “grain-free” was one of the fastest-growing labels in the pet food aisle. It sounded natural and wholesome. Then, in 2018, the US Food and Drug Administration announced it was investigating reports of a heart condition — dilated cardiomyopathy, or DCM — in dogs eating certain diets, many of them grain-free.
What is DCM?
Dilated cardiomyopathy is a disease of the heart muscle: the heart becomes enlarged and pumps weakly, which can lead to heart failure. It has a strong genetic component in some large breeds such as Dobermanns, Great Danes and Irish Wolfhounds. What caught vets’ attention was DCM in breeds not usually affected, such as Golden Retrievers, often on diets high in peas, lentils, other legumes and potatoes.
What we know
- Many of the reported dogs were eating diets in which legumes or potatoes were major ingredients, often labelled grain-free.
- Some dogs improved after changing diet and receiving treatment, which suggests diet played a role in those cases.
- In Golden Retrievers, some affected dogs had low taurine levels; many others did not.
What we don’t know
A cause-and-effect link has not been proven. Researchers are still investigating which ingredients, combinations or processing factors might be involved, and why some dogs are affected and most are not. The FDA has since said it will share new information when there is meaningful scientific progress.
Do dogs need grain-free food?
Very rarely. True grain allergies are uncommon in dogs; when dogs have food allergies, the triggers are more often proteins such as beef, dairy or chicken. Grains in commercial dog food are a useful source of energy and nutrients for most dogs.
What this means for your dog
- If your dog is healthy on a grain-free diet, don’t panic — but talk to your vet at your next visit about whether it is still the best choice.
- Choose foods from manufacturers that employ qualified veterinary nutritionists and do feeding trials or quality research.
- Watch for signs of heart trouble: tiring easily, coughing, fast breathing at rest, fainting or a swollen belly — and see your vet if you notice them.
- If your dog has been diagnosed with DCM, tell your vet exactly what they eat, including treats.
The lesson reaches beyond grain-free: marketing labels are not the same as nutritional evidence. The most useful questions to ask about any food are who formulated it, and how it was tested.
Questions owners ask
Should I stop feeding grain-free food?
If your dog has no medical need for grain-free food, many vets now suggest choosing a diet with grains from a well-established manufacturer. Discuss it at your next check-up.
Is taurine supplementation needed?
Only if your vet recommends it. Some dogs with diet-associated DCM had low taurine, but many did not. Blood tests can check levels.
Are grain allergies common in dogs?
No. Food allergies in dogs are more often triggered by proteins such as beef, dairy or chicken than by grains.
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