Why the aisle feels confusing

A lot of bags use “grain-free” the way a cereal box uses “natural”: as a selling point. Owners then hear two opposite stories. One says grains are the problem and grain-free is the upgrade. The other says grain-free food causes heart disease and you should never buy it. Neither story matches what the public scientific pages actually say.

What dilated cardiomyopathy is

The FDA describes dilated cardiomyopathy (DCM) as a disease of a dog’s heart muscle that results in an enlarged heart. As the heart and its chambers dilate, it becomes harder for the heart to pump, and heart valves may leak, which can lead to fluid buildup in the chest and abdomen. That fluid buildup is congestive heart failure. (Source: FDA Q&A on DCM)

The FDA says DCM has historically been linked mainly to genetics in certain breeds, often large or giant dogs such as Doberman Pinschers, Great Danes, and Irish Wolfhounds, and also in Cocker Spaniels in connection with taurine deficiency. The reports that started this investigation stood out because many involved breeds not previously known to have that genetic predisposition. (Source: FDA investigation page)

The same FDA Q&A says non-hereditary DCM appears to be a complex condition that may involve genetics, underlying medical conditions, and diet together. Diet factors they list as possible pieces include the nutritional makeup of ingredients and how dogs digest them, ingredient sourcing, processing, formulation, and feeding practices. The FDA also says it focuses on diet because it regulates animal food, not because diet is known to be the only cause. (Source: FDA Q&A on DCM)

What the FDA investigated

In July 2018, the FDA says it began investigating reports of DCM in dogs eating certain pet foods. Many were labeled “grain-free.” Those foods contained a high proportion of peas, lentils, other legume seeds (pulses), and/or potatoes in various forms — whole, flour, protein, and similar — as main ingredients. On the investigation page, “main ingredients” means listed within the first 10 ingredients, before vitamins and minerals. (Source: FDA investigation page)

For that label review, the FDA says it called a food grain-free if it did not contain corn, soy, wheat, rice, barley, or other grains. It also checked for peas, other lentils including chickpeas and beans, or potatoes including sweet potatoes. Of the products in those reported cases, the FDA says more than 90 percent were grain-free, and 93 percent had peas and/or lentils. A far smaller proportion contained potatoes. (Source: FDA investigation page, “Diet Information from Reported Cases”)

Read those percents as a description of the products named in the reports, not as the chance that a grain-free bag will make a dog sick, and not as a count of all grain-free foods on the market. The FDA says most dogs in the United States have been eating pet food without apparently developing DCM, and that it does not know how commonly dogs develop DCM. (Source: FDA investigation page)

The illnesses can be severe, even fatal. That is the FDA’s wording about why owners are right to care. It is not a claim that every dog on a grain-free diet will develop heart disease. (Source: FDA investigation page)

Where the public record stands

Checked October 8, 2026. The FDA investigation page still opens with a note dated December 23, 2022: the FDA does not intend to release further public updates until there is meaningful new scientific information to share. That note does not say the investigation is closed. It says the agency has followed up on a subset of reports, cannot investigate every report to verify it, and continues to encourage research by academia, veterinarians, and industry.

The same note says adverse-event numbers can be a signal, but by themselves they do not supply enough data to establish a causal relationship with the reported products. A later FDA Q&A says the FDA does not know the specific connection between these diets and non-hereditary DCM, and is still looking at genetics, underlying medical conditions, and other factors.

That Q&A, which includes reports through November 1, 2022, says the FDA has kept receiving DCM reports in dogs since its 2020 public communication, but at lower levels than from 2018 through 2020. The table on that page counts reports of DCM in dogs as:

  • 329 from January 1, 2014 through November 30, 2018
  • 190 from December 1, 2018 through April 30, 2019
  • 608 from May 1, 2019 through July 31, 2020
  • 255 from August 1, 2020 through November 1, 2022
  • 1,382 total from January 1, 2014 through November 1, 2022

Source: FDA Q&A, question 5, “How many reports of DCM has FDA received?”

The FDA’s footnotes matter. Those counts include reports in which a dog was simply stated to have been diagnosed with DCM, not only cases with full cardiology records. The agency followed up on a subset and cannot confirm every report. Reports are voluntary. The FDA says it does not know the background rate of non-hereditary DCM, so these numbers are not the true rate of disease in all dogs. Upticks in reports have tended to follow the FDA’s own public updates. An older table on the investigation page, covering January 1, 2014 through April 30, 2019 only, counted 515 canine reports, 560 dogs affected, and 119 deaths. That is a historical slice, not a running death total through 2022. (Source: FDA investigation page, “Cases Reported to FDA”)

On recalls, the FDA Q&A is direct: the agency has no definitive information indicating that the diets are inherently unsafe and need to be removed from the market. It is still working with others on how diet may interact with other factors. It is not planning to refresh its older list of commonly reported brands, because it knows several companies have changed formulas since the first announcements. (Source: FDA Q&A, questions 7 and 9)

Grain-free is not the same claim as “better”

The FDA says this is not an issue of grain-free diets only. It has received reports of non-hereditary DCM with both grain-free and grain-containing diets. Most of the diets in the reports had non-soy legumes and pulses, such as peas and lentils, high in the ingredient list.

The FDA also says legumes and pulses have been used in pet foods for many years, with no evidence they are inherently dangerous. What its data do suggest is that pulse ingredients are used in many grain-free diets in greater proportion than in most grain-containing formulas. Soy is a legume, and the FDA says it did not see a signal associated with soy. (Source: FDA Q&A, questions 6 and 8)

So a bag can be grain-free and still be a poor match for the pattern in the reports, or it can contain grain and still list several pulses near the top. The word on the front of the bag does not tell you which. “Grain-free” does not mean the food is medically better. “Contains grain” does not mean the food is a heart treatment. Neither label is a prescription.

What a Tufts veterinary nutrition page adds

Petfoodology is published by the Cummings School of Veterinary Medicine at Tufts University. A February 7, 2023 article by Lisa M. Freeman, DVM, PhD, DACVIM (Nutrition), is titled “Diet-associated dilated cardiomyopathy: The cause is not yet known but it hasn’t gone away.” It is a veterinary-school page, not an FDA ruling. Freeman’s disclosure on that page says she has received research or residency funding from, given sponsored lectures for, or provided professional services to Aratana Therapeutics, Elanco, Guiding Stars Licensing Co LLC, Hill’s Pet Nutrition, Nestlé Purina PetCare, P&G Petcare (now Mars), and Royal Canin. That does not erase the page. It is context for how you read it.

She cites the FDA count: another 255 dogs with DCM reported after July 2020, for a total of 1,382 dogs reported as of November 1, 2022. She writes that a lower number of recent reports might mean fewer cases, or it might mean fewer veterinarians and owners are reporting. She says diagnosing DCM takes an echocardiogram, which is not always done, and that filing a report takes time. (Source: Tufts Petfoodology, February 7, 2023)

On ingredients, she writes that the diets in question — she calls them non-traditional diets — are commonly grain-free commercial dry diets that contain pulses and, to a lesser extent, potatoes or sweet potatoes. She defines pulses as peas, lentils, chickpeas, and dry beans. She says soy has not been associated with this problem. She also says the association looks closer to pulses than to whether the diet contains grains. Some grain-inclusive diets contain pulses and can be associated with DCM as well.

She writes that most dogs with this form of DCM had been eating those diets for over a year, sometimes many years, so it does not seem to show up the week you switch bags, and that not every dog who eats these diets develops heart problems. On her page, a 2017 snapshot is given as context for how common the ingredients are: 51 percent of dry dog foods contained peas, 23 percent contained chickpeas, and 14 percent contained lentils. She says some research points to peas most, but that may simply reflect how much more often peas are used than other pulses, and that there is still a lot to learn about amount, processing, and pea fractions such as pea protein or pea fiber. (Source: Tufts Petfoodology, February 7, 2023)

Her page says the specific cause is not known. She writes that taurine deficiency can cause a secondary form of DCM and was an early suspect, but it has not been found in most dogs with diet-associated DCM, except in one study of Golden Retrievers. She says blood taurine may not be the best measure, so more research is needed. Her current hypothesis, stated as a hypothesis, is that compounds in these ingredients may have toxic effects on the heart. That is her reading. It is not an FDA finding on the pages checked for this article. (Source: Tufts Petfoodology, “Mechanisms”)

When her service diagnoses DCM, or earlier heart changes such as weaker contraction, enlarged chambers, or irregular heartbeats, she writes that they recommend a reduced-sodium diet that does not contain pulses or potatoes or sweet potatoes, together with medical treatment. She says the diet has to be chosen with the veterinarian for that pet. She also writes that if pulses sit in the top ten ingredients, or several pulses appear anywhere on the list, the diet might put some dogs at risk — and that you cannot tell from the product name or from whether it contains grains. You have to read the ingredient list. (Source: Tufts Petfoodology, “Where are we now?”)

Taurine, without the shortcut

It is tempting to turn this into “grain-free food lacks taurine, so add a supplement.” The FDA pages do not say that.

The FDA says taurine is generally not considered an essential amino acid for dogs, because dogs can make it from cysteine and methionine. In the product testing described on the investigation page, nearly all the grain-free products had methionine-cystine values above the 0.65 percent adult-maintenance minimum in the AAFCO Official Publication. Testing before the July 2018 update, for minerals, metals, and amino acids including taurine, did not reveal abnormalities. Later testing found similar average protein, fat, taurine, cystine, and methionine on a dry-matter basis for grain-free and grain-containing products in that sample. The FDA says it is still gathering information on whether taurine metabolism — absorption and excretion — plays a role. (Source: FDA investigation page, “Taurine & Amino Acids”)

The investigation page does say many cases of DCM in Golden Retrievers are taurine-deficient, and that owners who suspect a Golden Retriever may be affected may want to ask their veterinarian about taurine testing or an echocardiogram. That is a breed-specific note from the FDA, not a reason to start a supplement on your own. (Source: FDA investigation page, “Golden Retrievers”)

The FDA Q&A says veterinary cardiologists have reported some good results improving heart function in non-hereditary DCM, unlike genetic DCM, with appropriate veterinary treatment and dietary modification when the disease is caught early. It does not name a brand that prevents DCM, and it does not say that changing food replaces cardiac care. (Source: FDA Q&A, question 1)

What to do with the bag you already buy

  • Read the ingredient list, not only the front-of-bag diet claim. Look for peas, pea protein, pea fiber, lentils, chickpeas, beans, potatoes, and sweet potatoes, especially near the top.
  • Remember the FDA’s point: pulses in a recipe are not automatically dangerous, and grain-free is not automatically the issue. The open question is diets that use those ingredients in a high proportion, plus other factors the agency says are still unknown.
  • Do not switch foods because a friend, a store sign, or a social post said grain-free is healthier. Do not switch the other way in a panic and call that a treatment.
  • If your dog already has heart disease, ask your vet before any change. The FDA says your veterinarian is in the best position to advise you, and that the vet may consult a board-certified veterinary nutritionist. (Source: FDA Q&A)
  • If a veterinarian has already diagnosed DCM and recommended a diet change, follow that plan. Do not invent a substitute from a marketing label.
  • Bring the bag, or a photo of the full ingredient list, plus treats and toppers. The FDA says a dietary history should include all foods, including treats. (Source: FDA investigation page)
A label is not a prescription Nothing on this page says a grain-free food prevents dilated cardiomyopathy. Nothing here says every grain-free food causes it, or that every food with grain is safe. The FDA says it does not have definitive information that these diets are inherently unsafe and must come off the market. Tufts says the cause is still not known, and that a dog who already has DCM or earlier heart changes needs a veterinarian-guided diet and medical care — not a slogan.

When to call the vet

The FDA lists possible signs of DCM or other heart conditions: decreased energy, cough, difficulty breathing, and episodes of collapse. Contact your veterinarian as soon as possible. If the symptoms are severe and your veterinarian is not available, the FDA says you may need emergency care. (Source: FDA investigation page, “What you can do”)

  • Cough, trouble breathing, or fainting
  • A sudden drop in energy or exercise tolerance
  • A dog who already has a heart diagnosis, before you change food
  • A Golden Retriever you are worried about — ask about taurine testing or an echocardiogram, which is the FDA’s suggestion, not a home test

If your dog is diagnosed with DCM, Freeman asks owners to report it to the FDA so the investigation has a fuller record. Reporting is not a substitute for treatment.

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Bottom line

As of the FDA pages read on October 8, 2026, grain-free versus regular is not a settled heart verdict. The agency is looking at a possible, complicated link between some diets — often grain-free, often heavy in peas and other pulses, and sometimes grain-containing — and DCM in dogs. It says the reports do not prove a cause, it has not recalled the foods, and it does not plan another public update until there is meaningful new science. A Tufts veterinary nutritionist says the cause is still unknown, that the ingredient list matters more than the grain-free badge, and that a dog with DCM needs a vet-chosen diet plus medical care. Talk to your vet before you switch, especially if your dog has heart disease. Do not let a marketing label do the vet’s job.