Our Concerns With Grain-Free Diets
With so many pet food options on the market, choosing the right diet for your dog or cat can feel overwhelming. Dr. Christman has put together this guide to share what we know — and what we're still learning — about grain-free diets and heart disease in dogs.
Our Recommendation
If your dog or cat is currently eating a boutique, grain-free, vegetarian, vegan, or home-prepared diet, we recommend switching to a science-based diet from an established manufacturer — unless otherwise directed by your veterinarian.
We trust and recommend diets from Royal Canin, Purina, and Hill's, which employ board-certified veterinary nutritionists, conduct feeding trials, and use standard, well-tested ingredients. Transition gradually over 3–5 days to minimize stomach upset.
What's the Concern?
The link between grain-free diets and heart disease in dogs
In 2018, the FDA began investigating reports of dilated cardiomyopathy (DCM) — a serious heart condition — in dogs eating certain pet foods, many labeled "grain-free." DCM causes the heart muscle to become enlarged and weak, eventually leading to heart failure. It had historically been seen primarily in breeds with a genetic predisposition, but veterinarians were suddenly seeing it in breeds that had never been affected before.
By November 2022, the FDA had received 1,382 reports of DCM in dogs. More than 90% of the diets involved were grain-free, and 93% contained peas or lentils as primary ingredients. Research has increasingly pointed to high levels of pulses (peas, lentils, chickpeas) and legumes — commonly used to replace grains in these diets — as the strongest predictor for diet-associated DCM.
While the FDA concluded its public reporting in December 2022 stating there was insufficient data to establish a definitive causal link, veterinary researchers continue to study this issue actively. Studies from Tufts University and other institutions have found that dogs diagnosed with diet-associated DCM often show significant improvement when switched to traditional diets — a strong indicator that the diet itself is a contributing factor.
Three Categories of DCM
Not all DCM is created equal — understanding the difference matters
Breed-Specific (Genetic) DCM
Hereditary DCM that occurs in genetically predisposed breeds like Dobermans, Boxers, Great Danes, and Cocker Spaniels. This form is completely unrelated to diet.
Diet-Related DCM (Taurine Deficiency)
Caused by taurine deficiency in boutique and grain-free diets. Taurine is an amino acid essential for heart health, and some diets with high levels of legumes appear to interfere with taurine absorption.
Diet-Related DCM (Unknown Factors)
DCM linked to diet but not caused by taurine deficiency. Researchers believe other compounds in pulse-heavy diets may have toxic effects on the heart, but the specific mechanism has not yet been identified.
What Counts as "Grain-Free"?
Most grain-free pet foods will specifically state this claim on the packaging as a marketing strategy to make you believe that grain-free is healthier or more biologically appropriate for your pet.
Grain-free means the food does not contain corn, soy, wheat, barley, rice, or other grains. To compensate, these foods typically use potatoes, sweet potatoes, or legumes (peas, chickpeas, beans, lentils) as primary ingredients instead.
Importantly, recent research suggests the concern isn't simply about the absence of grains — it's about the high proportion of pulses and legumes used to replace them. Some grain-inclusive diets that also contain high levels of peas and lentils may carry similar risks.
🚩 Red Flags on the Label
- "Grain-free" prominently displayed
- Peas, pea protein, or pea fiber in top ingredients
- Lentils or chickpeas in top ingredients
- Potatoes or sweet potatoes as primary carb source
- Multiple legumes anywhere in the ingredient list
- Exotic proteins with limited research
- Boutique brands without veterinary nutritionists
If pulses appear in the top 10 ingredients — or multiple pulses appear anywhere in the list — the diet may put some dogs at risk.
Why Boutique Diets Are Risky
Not all pet food companies are created equal
The recent explosion of boutique pet food brands with outrageous label claims has made it incredibly difficult to select healthy, science-based options for your pet. Many of these companies do not employ veterinary nutritionists, lack rigorous quality control standards, and may inadvertently include ingredients that are toxic to dogs (such as onion or garlic).
Proper manufacturing of pet food is a complex process that requires appropriately educated veterinary nutritionists to ensure all required nutrients are present in the correct amounts and proportions. A food can look balanced on paper but perform very differently when actually fed to real animals over time.
✅ What We Recommend Trusted
Diets from established manufacturers that employ board-certified veterinary nutritionists, conduct AAFCO feeding trials, and use standard, well-tested ingredients like chicken, beef, rice, corn, and wheat. We trust Royal Canin, Purina, and Hill's.
🚫 What We Caution Against
Boutique brands, grain-free formulas, exotic ingredient diets, vegetarian or vegan pet foods, and home-prepared diets — unless specifically prescribed by a veterinarian for a diagnosed medical condition.
Signs Your Dog May Be Affected
If your dog shows any of these symptoms, schedule an appointment as soon as possible
Decreased energy or lethargy
Loss of appetite
Labored breathing
Persistent cough
Collapse or fainting
Concerned about your pet's diet? Schedule an appointment to discuss your pet's nutrition and whether an echocardiogram may be appropriate to screen for non-symptomatic heart disease.
📋 Where Things Stand: FDA Investigation Update
In December 2022, the FDA announced it would no longer publish routine updates on its DCM investigation, stating that the adverse event reports received "do not supply sufficient data to establish a causal relationship" between grain-free diets and DCM. However, the FDA also emphasized that it "continues to encourage research and collaboration by academia, veterinarians, and industry."
It's important to understand what this means: the FDA did not say grain-free diets are safe. They said they didn't have enough data from their reporting system alone to prove a definitive cause. Meanwhile, peer-reviewed veterinary research continues to find strong associations between high-pulse diets and heart disease in dogs, and veterinary cardiologists continue to diagnose and treat diet-associated DCM.
Our recommendation remains unchanged: choose established, science-based diets and avoid grain-free formulas unless specifically prescribed by your veterinarian.
Questions About Your Pet's Diet?
We're always here to answer your questions and help you make the best choices for your pet's health. Don't hesitate to reach out.