The grain-free DCM concern, six years on.

What DCM is.

Dilated cardiomyopathy is a disease of the heart muscle in which the chambers of the heart enlarge and weaken. 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. It is not a diet-caused disease in dogs predisposed to it.

What the 2018 FDA notice said.

In July 2018 the FDA Center for Veterinary Medicine 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. The notice was an investigation announcement, not a finding.

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.

What later research found.

Between 2019 and 2023, multiple academic papers examined the question. Findings were inconsistent. Some case series found taurine deficiency in some affected dogs; others did not. Some studies found correlations between grain-free diets and reduced cardiac function on echocardiogram; others did not. Several critiques pointed out that the FDA case database over-represented breeds and feeding patterns that were already known DCM risks.

By December 2022 the FDA effectively wound down public updates on the investigation, citing the difficulty of drawing causal conclusions from voluntary case reports. There has been no causal finding to date.

What changed in the market anyway.

The trust damage was done. Several boutique grain-free brands reformulated to add grains or removed lentils and peas from their main recipes. Veterinarians who had previously 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 moved from a premium positioning marker to a category-wide caveat.

How PetScored handles this.

We do not credit grain-free on any dimension of the rubric. We also do not penalize it. The Sensitivity Risk sub-score does flag legumes, peas, and pulses as common-trigger ingredients on a sensitivity panel — not because of DCM but because the adverse-food-reaction literature names them. That is the limit of what the label evidence supports.

If your dog is a breed with known DCM risk, talk to a veterinary cardiologist about diet, not a pet food rating site. We will not score a question that clinical medicine has not answered.

What we will not 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. Related: Why we don’t credit grain-free.