The Canine Ledger

Grain-Free and DCM: What the FDA Found, and What Is Still Unknown

The FDA investigated grain-free food and heart disease in dogs from 2018. What it found, what two later studies add, and what to ask your vet.

Written by thecanineledger

If your dog has low energy, a cough, trouble breathing or has collapsed, contact your vet as soon as possible. If the signs are severe and your vet isn’t available, go to an emergency clinic. Those are the signs the US Food and Drug Administration lists for dilated cardiomyopathy and other heart conditions (FDA, investigation page).

Between January 2014 and November 2022, the FDA received 1,382 reports of dilated cardiomyopathy (DCM) in dogs (FDA, Questions & Answers on non-hereditary DCM). Many involved dogs eating foods labelled “grain-free”.

Then, in December 2022, the agency said it “does not intend to release further public updates until there is meaningful new scientific information to share.” No cause had been found.

While the story is often told as “grain-free food causes heart disease”, the evidence doesn’t support a statement that simple, in either direction. This page sets out what the FDA found, what two later studies add, and what is still unknown.

1. What DCM is

The FDA describes DCM as “a disease of a dog’s heart muscle and results in an enlarged heart.” As the heart stretches, it pumps less well, and fluid can build up in the chest and abdomen. This is congestive heart failure.

DCM has long been linked to genes in certain breeds. The FDA’s concern was a different, non-hereditary form, which it says “may be affected by the interplay of multiple factors such as genetics, underlying medical conditions, and diet.”

The FDA also notes that cardiologists report “some good results in improving heart function in non-hereditary DCM cases” with treatment and a change of diet, “when caught early in the progression of the disease.”

2. What the FDA found

The FDA announced its investigation in July 2018. It said the foods involved were often labelled “grain-free” and contained “a high proportion of peas, lentils, other legume seeds (pulses), and/or potatoes in various forms” as main ingredients.

PeriodWhat the FDA reported
1 January 2014 to 30 April 2019515 reports in dogs, covering 560 dogs, 119 of which died
1 January 2014 to 1 November 20221,382 reports in dogs

Three points from the FDA matter when reading those numbers:

  • Reports aren’t proof. The FDA says report numbers alone “do not supply sufficient data to establish a causal relationship with reported product(s).”
  • The reports rose after the news. The FDA says “the vast majority of the reports were submitted after the agency notified the public” in July 2018.
  • Grain-free isn’t the whole story. The FDA received reports linked to “both grain-free and grain-containing diets.” What most had in common was peas, lentils and similar ingredients “high in their ingredient lists.”

The FDA also put the numbers in context. It cited an estimate of 77 million pet dogs in the US, and wrote: “Most dogs in the U.S. have been eating pet food without apparently developing DCM.”

In 2019 the FDA published a graph of the brands named ten or more times in reports. We don’t repeat them. The FDA has since said it is “not planning to update the commonly reported brands”, because “several pet food companies have adjusted diet formulations”. It also says it has “no definitive information indicating that the diets are inherently unsafe and need to be removed from the market”.

Our note: We don’t repeat the FDA’s 2019 brand list. The FDA hasn’t updated it and says it has no definitive information that the diets are unsafe.

3. What about taurine?

Taurine came up because taurine deficiency is a known cause of DCM in cats and some dogs. But the FDA notes that taurine is “generally not considered an essential amino acid for dogs, because these animals can synthesize taurine from cysteine and methionine.”

Our note: We found no current guidance on whether vets should test taurine in dogs with DCM on these diets. The FDA’s investigation page says owners of Golden Retrievers that may be affected “may wish to consult their veterinarian to discuss checking taurine levels or conducting an echocardiogram.” At one US university hospital, taurine was measured in 20 of 71 dogs diagnosed with DCM between 2014 and 2018 (Freid et al., Journal of Veterinary Internal Medicine 2021). That shows what one hospital did then, not what vets do now.

4. What later studies add

Two studies give a sense of where the research has gone. Neither settles the question.

A large study of owner reports (2026). Researchers used data from the Dog Aging Project, a long-running US study of pet dogs (O’Brien et al., Vet Med Sci 2026). They looked at whether dogs whose owners said they ate grain-free food were more likely to get any new heart diagnosis over two years. The odds ratio was 1.05, “suggesting no effect.” The authors concluded any effect “is likely minimal or absent.”

Two limits matter. The study counted owner-reported heart diagnoses of any kind, not DCM confirmed by a heart scan. And owners often got the diet wrong: the authors found “a large misclassification error in the diets reported to be grain-free.” They concluded this was unlikely to change the result much.

A small study of heart scans (2023). Researchers scanned the hearts of 46 healthy dogs, half eating “nontraditional” diets and half eating traditional ones (Owens et al., J Vet Intern Med 2023). The dogs on nontraditional diets had lower average pumping function: an ejection fraction of 48.65%, against 56.65%. The authors concluded that such dogs “had lower indices of systolic function and larger left ventricular volumes”.

That study was small and took a single snapshot. It shows a difference in healthy dogs, not that the diets cause disease.

Our note: We read only the abstracts of these two studies, not the full texts or their funding and conflict statements.

5. What to ask your vet

The FDA encourages owners “to work with their veterinarians, who may consult with a board-certified veterinary nutritionist, prior to making diet changes.” Useful questions:

  • Does my dog’s breed have a known risk of DCM?
  • Does my dog’s current food concern you, given what’s high in its ingredient list?
  • Should my dog have a heart check, and what would it involve?
  • If you’d suggest a different food, what should I look for on the label? → How to Read a Dog Food Label

Bring a full list of what your dog eats, including treats. The FDA says your vet “may ask you for a thorough dietary history”.

Our note: The opening box uses the FDA’s list of signs. Fainting or a swollen belly also need a vet promptly.

6. What we could not verify

Commonly saidWhat we found
“Grain-free food causes DCM”Not established. The FDA found no cause and hasn’t asked for recalls.
“Grain-free food is safe for every dog”Not established either. The question is still open.
“Grains are the issue”Not what the FDA said. Its reports pointed to peas, lentils and similar ingredients, in grain-free and grain-containing foods.
“Adding taurine prevents DCM”We found no source we could read that shows this.

Sources

Always confirm with your vet before acting on anything on this page.