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Grain-free dog food and the FDA's DCM investigation: what the evidence actually says

The FDA opened an investigation into a possible link between grain-free dog food and canine dilated cardiomyopathy (DCM) in July 2018. The agency ended routine public updates in December 2022. The investigation is paused, not closed, and the scientific question remains unresolved. This guide explains what the FDA actually concluded, the pulses-vs-grains distinction that the headline coverage usually misses, which dogs are at higher risk, and what to ask your veterinarian before changing your dog's diet.

What the FDA actually concluded (and did not conclude)

Three honest beats. First, the FDA never established causation between grain-free formulations and canine DCM. Second, the FDA never cleared grain-free either. Third, the FDA tracked 1,382 case reports of canine DCM between January 2014 and November 2022 and stated those numbers, by themselves, are not sufficient to establish a causal relationship.

The agency ended routine public updates on the investigation in December 2022. As reported in the AVMA's February 2023 summary, the FDA continues to investigate but has paused the cadence of public communications pending more science. The pause is not a closure.

DCM (dilated cardiomyopathy): a heart muscle disease where the chambers enlarge and the heart's ability to pump weakens. It progresses to congestive heart failure and is fatal without treatment. Some breeds carry inherited DCM risk. The FDA's investigation focused on cases appearing in breeds without that inherited predisposition, which raised the diet question.

Timeline of the FDA investigation: 2018 to today

The investigation has unfolded across more than six years. Six dated beats with primary-source links.

  1. FDA opens the investigation

    The FDA issues an initial alert about reports of canine dilated cardiomyopathy in dogs eating diets with peas, lentils, other legume seeds, and potatoes as main ingredients.

  2. First detailed update

    FDA reports approximately 300 cases of canine DCM, with a notable pattern in breeds not historically predisposed.

  3. 16 brands named

    FDA publishes the 16 brands most frequently reported in DCM cases, with an explicit caveat that being named is not proof of causation. Coverage of the brand list ran widely in mainstream press.

  4. Case count grows

    FDA update reports more than 1,100 cumulative case reports, continuing to investigate the diet pattern.

  5. FDA ends routine public updates

    FDA announces it will end routine public updates pending more science. The investigation does not close; the public communications cadence ends.

  6. Lawsuit context

    A $2.6 billion lawsuit filed against Hill's Pet Nutrition alleges the investigation was fraudulently induced. The district court dismissed the case in November 2024; it is on appeal as of 2026. The legal action does not change the underlying veterinary cardiology question.

Routine FDA updates ended in late 2022, but veterinary cardiologists at Tufts and elsewhere continue to report seeing diet-associated DCM cases in clinical practice. The question is open, not closed.

Pulses vs grains: what the FDA's concern actually is

This is the headline most coverage misses. The FDA observed that more than 90% of reported diets were grain-free and 93% contained peas or lentils. The two correlate because pulses (peas, lentils, chickpeas, dry beans) are the most common protein-bulk substitute when grains are removed from a kibble. The FDA's concern was the pulses-as-bulking pattern, not the absence of grains.

Pulses: dried edible seeds of legume plants. The category includes peas, lentils, chickpeas, and dry beans. Pulses are nutritionally dense and high in plant protein, which is why they appear in pet food as economical protein-volume bulking ingredients.

A grain-free recipe built on a named animal protein (chicken, salmon, beef) with low pulse load is mechanically different from a grain-free recipe where peas and lentils crowd the named animal protein in the top five ingredients. The two formulations get treated as the same thing in mainstream coverage and they are not the same thing.

Lisa Freeman, DVM, PhD, DACVIM (Nutrition) at Tufts Cummings School calls the pattern of concern BEG diets: Boutique manufacturer, Exotic protein, Grain-free. Per Tufts Petfoodology, the boutique-exotic-grain-free combination is what veterinary cardiologists flag, not grain-free alone. Freeman also reported that in 2017, 51% of dry dog foods contained peas, 23% contained chickpeas, and 14% contained lentils.

The evidence base disagrees with itself, and honest coverage says so. A University of Guelph 2023 study fed dogs diets containing up to 45% whole pulse ingredients for 20 weeks without observing a cardiac signal. The Guelph result does not invalidate the FDA's case reports; it does suggest that pulse load alone is not the whole story.

Which dogs are at higher risk

Breed risk separates cleanly into two categories: dogs that carry inherited DCM risk independent of diet, and dogs that appeared in the FDA's atypical-DCM case reports.

Breeds with genetic predisposition to DCM (independent of diet)

These breeds carry inherited cardiac risk that predates the diet hypothesis by decades. Owners of these breeds should discuss baseline cardiac screening with their veterinarian regardless of what the dog eats.

Breeds that appeared in atypical-DCM reports during the FDA investigation

These breeds are not historically predisposed to DCM, which is why the FDA case clustering raised the diet-association question. For atypical-breed owners, scrutinizing a pulse-heavy formula carries more weight than it does for owners of historically-low-risk breeds. A Golden Retriever owner has a stronger reason to examine the ingredient list than a Beagle owner does. No breed is being recommended against grain-free as a category; the decision belongs with a veterinarian who knows the individual dog.

The taurine angle: when DCM is diet-responsive

A subset of diet-associated DCM cases, especially in Golden Retrievers and Cocker Spaniels, is taurine-responsive. Supplementation plus a diet change can reverse the cardiac changes in those cases. The Kaplan et al. Golden Retriever taurine study (PMC7228784) documented this responsive subset.

Many other cases are not taurine-responsive. Normal blood taurine does not rule out diet-associated DCM. This is one reason veterinary cardiologists do not treat "my dog's taurine is normal" as reassurance on its own. The decision to supplement taurine, like the decision to change the diet, belongs with a veterinarian who has run an echocardiogram and a taurine panel. Self-supplementing without diagnosis can mask symptoms without addressing the underlying recipe issue.

Taurine: an amino acid synthesized by dogs from methionine and cysteine. Dogs do not strictly require dietary taurine the way cats do, but some breeds and some diets can produce taurine-deficient cardiac changes. Taurine is concentrated in animal tissue, especially heart and dark meat.

When grain-free is appropriate (and when it isn't)

The appropriate-use question is narrower than marketing suggests. The inappropriate-use list is longer.

Appropriate use cases for grain-free

Not strong reasons for grain-free

How to read a grain-free label without getting lost

Four steps to apply to any grain-free bag you are considering.

  1. Check the first five ingredients. If two or more are pulses (pea protein, pea flour, lentils, chickpeas, pea fiber), the recipe is pulse-stacked.
  2. Watch for the "pea protein + pea fiber + whole peas" pattern. This is ingredient splitting. Each pea fraction lists separately, so individual fractions appear lower than their combined weight. The how to read a dog food label guide walks through the splitting trick on a real label.
  3. Confirm a named animal protein in the top two ingredients. Chicken, beef, salmon, lamb. Not "poultry meal" or "meat by-products" without a species. The named vs unnamed proteins guide covers why this distinction matters.
  4. Note where the first pulse appears. First-pulse-at-position-6-or-later is mechanically different from first-pulse-at-position-2. The position of the first pulse is the single most useful number on a grain-free panel for the DCM-anxious owner.

What to ask your vet before switching to or away from grain-free

Screenshot this. Take it to your next appointment. The list is designed for the conversation, not for self-diagnosis.

  1. Given my dog's breed and age, what is their baseline DCM risk?
  2. Should we run a baseline echocardiogram or a taurine panel before changing the diet?
  3. Is there a documented clinical reason for grain-free in my dog's case, or is this owner-driven?
  4. If grain-free, can you recommend formulas that are not pulse-stacked?
  5. What symptoms should I watch for that would warrant an immediate cardiology referral?
  6. Should we plan a re-check at six or twelve months?
  7. Do you consult a board-certified veterinary nutritionist (DACVN), and is that appropriate for our case?

How Moesonson scores pulse-heavy formulas

Moesonson's analyzer evaluates the named-animal-protein share of every label. Pulses listed in the top five ingredients reduce a recipe's named-animal-protein-share score because they bulk protein quantity without contributing the amino acid profile a named animal protein provides. This is the same scoring rule applied to every recipe in our database; it appears on every per-product page.

This is a methodology choice, not a medical claim. Moesonson does not assert that a low-pulse formula prevents DCM, and we do not treat the scoring as veterinary guidance. The scoring reflects a position on what high-quality protein sourcing looks like. The position is informed by the FDA's pulses-as-bulking concern but is not contingent on causation being proven. The scoring stands or falls on the ingredient-sourcing argument, not the DCM argument.

See our grain-free dog food picks for current recipes that clear our floor (low pulse load, named animal protein in the top ingredients). Moesonson sells nothing, takes no affiliate revenue, accepts no manufacturer sponsorship, and accepts no supplement-brand sponsorship. There is no commercial incentive to push pet owners toward or away from grain-free as a category.

Frequently asked questions

Did the FDA actually conclude that grain-free dog food causes DCM?

No. The FDA stated: "While adverse event numbers can be a potential signal of an issue with an FDA regulated product, by themselves, they do not supply sufficient data to establish a causal relationship with reported product(s)." The agency ended routine updates in December 2022 pending more science. The question is unresolved, not closed.

Are peas bad for dogs?

Not in small quantities. The FDA's investigation observed that more than 90% of reported diets were grain-free and 93% contained peas or lentils. The concern is pulse-stacked formulations where peas, pea protein, and lentils dominate the protein column, not the presence of peas at moderate levels.

Should I switch my dog away from grain-free right now?

Not without a vet conversation. Abrupt diet changes cause their own gastrointestinal problems. The decision depends on your dog's breed, age, current cardiac status, and whether the current diet is pulse-stacked or low-pulse. Use the "what to ask your vet" checklist below as a starting point.

What is a BEG diet?

BEG stands for Boutique manufacturer, Exotic protein, Grain-free. The framing comes from Lisa Freeman, DVM, PhD, DACVIM (Nutrition) at Tufts Cummings School. Veterinary cardiologists flag the BEG pattern more than they flag grain-free alone; the boutique-and-exotic dimensions matter to the formulation question.

Is taurine supplementation the answer?

Only for taurine-responsive cases diagnosed by a veterinarian. A subset of diet-associated DCM cases (especially in Golden Retrievers and Cocker Spaniels) responds to taurine supplementation plus a diet change. Many cases do not. Normal blood taurine does not rule out diet-associated DCM. Do not start supplementation without a vet panel.

My dog is a Doberman, Boxer, or Great Dane: should I avoid grain-free?

These breeds carry genetic predisposition to DCM that predates the diet hypothesis by decades. Talk to your veterinarian about appropriate cardiac screening for your specific dog. Do not assume grain-free is the variable; the inherited risk is independent of diet.

See also

Sources

  1. U.S. Food and Drug Administration. FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy. Last updated 2022.
  2. American Veterinary Medical Association. Until more science is available, FDA will end public updates on potential link between certain diets and canine DCM. February 7, 2023.
  3. Freeman LM. Diet-Associated Dilated Cardiomyopathy: The Cause is Not Yet Known but It Hasn't Gone Away. Tufts Cummings School Petfoodology. February 7, 2023.
  4. Kaplan JL et al. Development of plasma and whole blood taurine reference ranges and identification of dietary features associated with taurine deficiency and dilated cardiomyopathy in Golden Retrievers. PLOS ONE / PMC7228784.
  5. University of Guelph. Peas of Mind: Pulse Ingredients in Dog Food Not Linked to Heart Problems, Says New U of G Research. April 2023.
  6. Quilliam C et al. Effects of a 28-day feeding trial of grain-containing versus pulse-based diets on cardiac function in dogs. PMC10212094.
  7. Pet food regulatory review. Grain-Free Diets for Dogs and Cats: An Updated Review. PMC12291746, 2024.

About this guide

Published by Moesonson Editorial. Moesonson is a pet-food analyzer published by an organization, not an individual credentialed veterinarian. For medical authority, this page relies on the cited primary sources (FDA, AVMA, Tufts Cummings, peer-reviewed PMC studies) and is intended as a literature review for pet owners, not as veterinary advice. Medical review by a board-certified veterinarian is pending.

Moesonson takes no affiliate revenue, no brand sponsorships, and no supplement-brand sponsorships. On a YMYL topic where the reader is reasonably anxious about manufacturer capture, we think this disclosure belongs on the page.

Reviewed by the Moesonson editorial team Last updated June 29, 2026 Medically reviewed by: TBD