The grain-free DCM concern, six years on.

Start here: what DCM actually is.

Dilated cardiomyopathy, DCM for short, is a disease of the heart muscle in which the chambers of the heart enlarge and weaken. The part worth holding onto is this: it is a known, mostly genetic condition in specific breeds, Doberman Pinschers, Boxers, Great Danes, Irish Wolfhounds, Cocker Spaniels. In those breeds, DCM has been studied for decades. In dogs predisposed to it, this is not a disease the bowl creates. That matters before any conversation about food even begins.

What the 2018 FDA notice really said.

Here is the source of the worry, in plain terms. In July 2018 the FDA Center for Veterinary Medicine, the part of the agency that oversees pet food, published a notice saying it was investigating reports of DCM in dogs eating diets that often, though not always, contained peas, lentils, legumes, or potatoes as main ingredients. Many of those diets were marketed as grain-free. Read the notice for what it was: an announcement that the agency was looking into something, not a finding that it had found something.

That distinction got lost. Pet media and breed forums treated the notice as confirmation that grain-free caused DCM. It was not. The FDA itself repeatedly clarified that a causal link had not been established. If you came away from 2018 thinking the case was closed, the headlines, not the evidence, are why.

What the research found after that.

You would hope the years since settled it cleanly. They did not, and that is the honest answer. Between 2019 and 2023, multiple academic papers examined the question, and the findings were inconsistent. Some case series found taurine deficiency, a shortage of an amino acid dogs need, in some affected dogs. Others did not. Some studies found correlations between grain-free diets and reduced heart function on echocardiogram, the ultrasound vets use to look at the heart. Others did not. Several critiques pointed out that the FDA case database over-represented breeds and feeding patterns that were already known DCM risks, which muddies the picture further.

By December 2022 the FDA effectively wound down its public updates on the investigation, citing how hard it is to draw causal conclusions from voluntary case reports. The bottom line you can carry out of all this: there has been no causal finding to date.

Why the shelf changed anyway.

Even without a finding, the market moved, which is why the food you see today looks different. The trust damage was done. Several boutique grain-free brands reformulated to add grains, or pulled lentils and peas out of their main recipes. Veterinarians who had been agnostic became openly skeptical of grain-free diets, especially for breeds with genetic DCM risk. Insurance underwriting for breeds like Doberman Pinschers added pet-food questions. The phrase “grain-free” quietly slid from a premium selling point to a category-wide caveat. So if grain-free now feels faintly suspect to you, that feeling is marketing fallout, not a verdict from the science.

So how do we handle it.

Here is what this means for the score you see from us. We do not give grain-free any credit on the rubric. We also do not dock it. Our Sensitivity Risk sub-score does flag legumes, peas, and pulses as common-trigger ingredients, and to be clear, that flag is not about DCM. It is there because the adverse-food-reaction literature, the research on what dogs react to, names them. That is the limit of what a label can honestly support, so it is the limit of what we will claim.

And if your dog is a breed with known DCM risk, this is the part to take to heart: talk to a veterinary cardiologist about diet, not a pet food rating site. That is a conversation about your dog, and we are not the right tool for it. We will not score a question that clinical medicine has not answered.

And the things we will never do.

• Subtract points from grain-free recipes by default.
• Credit grain-inclusive recipes for the absence of legumes.
• Cite the FDA notice as evidence of a causal link.
• Imply your specific dog will or will not develop DCM based on the food it eats.

- The PetScored desk. If you want the shorter version of our stance, read Why we don’t credit grain-free.