Grain-free dog food became hugely popular because it sounds simple: if grains aren’t necessary for dogs, why include them?
But the conversation changed when veterinarians began reporting cases of dilated cardiomyopathy (DCM) in dogs eating certain grain-free and other non-traditional diets.
So what does the science say now?
The answer in 2026 is more nuanced than:
“Grain-free food causes heart disease.”
But it is also more concerning than:
“The grain-free controversy was completely disproven.”
Current evidence points toward a potential relationship between diet-associated DCM and diets high in pulses such as peas, lentils, chickpeas and beans, rather than simply the absence of grains. The exact mechanism has not yet been established.
What Is DCM?
Dilated cardiomyopathy, or DCM, is a disease in which the heart muscle becomes weakened and the heart chambers can become enlarged.
Some forms of DCM are strongly associated with genetics.
Doberman Pinschers, Great Danes and other large breeds are well-known examples of dogs with inherited predispositions to DCM.
But veterinarians have also identified a different form of DCM that appears to be associated with nutritional factors.
This is where the grain-free debate began.
How Did Grain-Free Food Become Linked to DCM?
In 2018, the US Food and Drug Administration (FDA) announced an investigation after receiving reports of DCM in dogs eating certain diets.
Many of those diets were labelled grain-free and contained substantial amounts of peas, lentils, other legumes or potatoes. Importantly, some affected dogs belonged to breeds that were not traditionally considered genetically predisposed to DCM.
The FDA later emphasised that the situation was complex.
Reports involved both grain-free and grain-containing foods, while many of the diets associated with reports contained pulses high in the ingredient list. The FDA stated that it still did not know the specific connection between these diets and DCM.
That distinction is critical.
The concern isn’t simply “grains versus no grains.”
What Does the Evidence Say in 2026?
The evidence has continued to develop.
A June 2026 update from Tufts University veterinary nutritionist Dr Lisa Freeman summarised the current understanding as follows: diet-associated DCM appears to be associated particularly with diets high in pulses, including peas, lentils, chickpeas and beans. These diets can be either grain-free or grain-inclusive.
More than 30 scientific studies have now contributed to the investigation, according to Freeman’s 2026 review. However, the precise cause of the heart injury remains unresolved.
Researchers have investigated several possible mechanisms, including nutrient availability, taurine metabolism, fibre and changes in the gut microbiome.
More recent work has also identified potential metabolic changes, including a possible connection with phospholipidosis, but this remains an area of active research rather than a definitive explanation.
A 2025 peer-reviewed review likewise concluded that substantial evidence now points toward an association between diet and DCM, particularly diets rich in legumes, while emphasising that further research is needed to identify the exact mechanism.
Is Grain-Free Food Itself the Problem?
Not necessarily.
This is probably the most important point in the entire debate.
The FDA has received reports involving both grain-free and grain-containing diets. The common feature in many reports has been the presence of pulses—particularly peas and lentils—high in the ingredient list.
So:
Grain-free ≠ automatically dangerous.
And:
Grain-inclusive ≠ automatically safe.
A grain-containing food can still contain large amounts of pulses.
The more useful question is therefore:
What does the complete formulation look like, and how much reliance does it place on pulses or other unusual ingredients?
Which Breeds Are Most at Risk?
There are actually two different questions here.
Breeds genetically predisposed to DCM
Traditional inherited DCM is particularly associated with breeds such as:
Doberman Pinscher
Great Dane
Irish Wolfhound
Newfoundland
and other large or giant breeds.
Cocker Spaniels are also recognised in connection with taurine-related DCM.
Breeds affected by diet-associated DCM
This is different.
Diet-associated DCM has been reported across a much broader range of breeds, including dogs that are not genetically predisposed to the disease.
Golden Retrievers deserve particular attention because they have been disproportionately represented in reports involving taurine deficiency and diet-associated DCM. Research has also identified possible susceptibility to taurine deficiency in breeds including Golden Retrievers, Newfoundlands, Cocker Spaniels, English Setters and Labrador Retrievers.
That does not mean every Golden Retriever should avoid every grain-free food.
It means breed, diet and individual health should be considered together.
What About Taurine?
Taurine became one of the major theories behind the DCM investigation.
Taurine is involved in normal heart function, and taurine deficiency can cause a secondary form of DCM in dogs.
However, current research suggests that the newer form of diet-associated DCM cannot simply be explained by a lack of taurine.
The June 2026 Tufts update states that diet-associated DCM does not appear to be caused simply by a deficiency of taurine or other nutrients.
That is why adding taurine to a questionable diet should not be viewed as a simple solution.
If you are concerned about taurine, heart health or your dog’s diet, speak to your veterinarian rather than adding supplements yourself.
When Might Grain-Free Food Be Appropriate?
There are legitimate reasons a veterinarian might recommend a grain-free diet for an individual dog.
For example, a dog may have a specific dietary requirement or intolerance that makes a particular formulation appropriate.
But “my dog doesn’t eat grains in the wild” is not, by itself, a nutritional argument.
Nor is grain-free automatically healthier.
If a dog has no specific reason to avoid grains, there is generally no need to choose grain-free simply because it appears more natural or premium.
The important consideration is the complete nutritional formulation.
What Should You Look for on a Grain-Free Label?
If you’re considering a grain-free food, look beyond the words “grain-free.”
Check the ingredient list for pulses such as:
peas;
lentils;
chickpeas;
beans.
Pay particular attention when several pulse ingredients appear high in the ingredient list.
The FDA has noted that many diets involved in its investigation contained pulses high in the ingredient list.
Also check:
1. Is it complete and balanced?
Make sure it is appropriate for your dog’s life stage.
2. Who formulated it?
Look for appropriate nutritional expertise.
3. Who manufactures it?
Find out whether the company manufactures the food itself or uses a third party.
4. What quality control is used?
A manufacturer should be able to explain how ingredients and finished products are tested.
5. What evidence supports the diet?
These are the same questions recommended by WSAVA when evaluating pet food manufacturers.
Should You Stop Feeding Grain-Free Food?
Don’t make a sudden diet change based solely on an internet article.
If your dog is currently eating a grain-free diet and is healthy, discuss the diet with your veterinarian—particularly if the food is heavily reliant on peas, lentils or other pulses.
The FDA continues to describe the underlying cause as unresolved and recommends that owners work with their veterinarians when considering diet changes.
Dogs with symptoms such as:
reduced exercise tolerance;
weakness;
fainting;
coughing;
or difficulty breathing
should be assessed by a veterinarian promptly because these can be signs of heart disease, although they can also have many other causes.