Yes, you read it right. Non-hereditary (nutritional) dilated cardiomyopathy linked to grain free and boutique/exotic diets is still a problem, and it was never a case closed. However, unfortunately pet owners and even some vet professionals interpreted the FDA’s statement in 2022 to mean that nDCM was cancelled, done, finished, finito. We didn’t need to worry about grain free diets anymore, War Is Over – If You Want It…
Except, that wasn’t what the FDA actually said:
FDA does not intend to release further public updates until there is meaningful new scientific information to share. A count of reports of DCM in dogs submitted to FDA as of November 1, 2022, has been added to Questions & Answers: FDA’s Work on Potential Causes of Non-Hereditary DCM in Dogs. FDA has followed up on a subset of these reports, but is unable to investigate every report to verify or confirm the reported information. 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). FDA continues to encourage research and collaboration by academia, veterinarians, and industry.
What they meant was – they didn’t have the resources to investigate each and every report that had been made to them about grain free diets, and they aren’t in the business of research or academia. The FDA doesn’t conduct research, they are merely there to advise people when an adverse event occurs or if there is a trend of reporting. See my post for more on my interpretation of the FDA statement:
But I thought there was no established link between grain free diets and DCM?
Well, academia would disagree – since the FDA’s statement in 2022, research has not slowed down on this disease. As it currently stands, there is a link between grain free diets and DCM, but the mechanism of developing illness in breeds that don’t have a genetic predisposition for heart disease. What we do know however, is that the key component in these diets is the high proportion of peas, pulses and legumes which has formed the basis for further investigations into the cause of nutritional DCM. If you want to go back in time and look at what we’ve previously learnt about nDCM, check out my post here.
What does the research say? What’s new in the world of nDCM?
Here’s a couple of recent studies that have added to the growing body of evidence around high pulse grain free diets, and the impact they have on the heart:
1. Freeman, L. M., Rush, J. E., Berridge, B. R., Mitchell, R. N., & Martinez-Romero, E. G. (2025). Dogs with diet-associated dilated cardiomyopathy have higher urine di-docosahexaenoyl (22:6)-bis(monoacylglycerol)phosphate, a biomarker of phospholipidosis. American Journal of Veterinary Research, 86(1), ajvr.24.07.0211. Retrieved Apr 4, 2025, from https://doi.org/10.2460/ajvr.24.07.0211
In this study, HP [high pulse] diets were significantly associated with higher normalized urine di-22:6-BMP concentrations. While this is only a first step in studying this possible connection, these findings support primary or secondary phospholipidosis as a potential mechanism for diet-associated DCM….These results support the possible presence of primary or secondary phospholipidosis in dogs with diet-associated DCM and provide a plausible mechanism that fits with EM [electron microscopic] findings in these dogs.
So what does that even mean? Well, phospholipidosis is a condition where something (often drugs) causes an overaccumulation of a type of fat, inside cells, potentially leading to organ damage. It is possible that the accumulation of fat is resulting in cardiac damage, induced by the consumption of a high pulse diet.
2. Baek, M., Choi, M., Chae, Y., Yun, T., Kang, B.-T., & Kim, H. (2024, September 30). Grain-free diet-induced dilated cardiomyopathy with atrial fibrillation in a Labrador Retriever: a case report. Korean Journal of Veterinary Research. The Korean Society of Veterinary Science (KJVR). https://doi.org/10.14405/kjvr.20240025
An 11-year-old female dog was referred with abdominal distention, anorexia, and vomiting, having been fed a grain-free diet for more than 5 years. Thoracic radiography revealed cardiomegaly and pulmonary edema. Atrial fibrillation was detected using electrocardiography. The dog was tentatively diagnosed with congestive heart failure (CHF) secondary to grain-free diet-induced DCM, and its diet changed to contain grain. Digoxin and diltiazem were prescribed for the atrial fibrillation, and pimobendan, enalapril, and furosemide for CHF. Significant improvements in echocardiographic indices were confirmed after 3 months.
The last sentence is the key here. After 3 months, significant improvements were noted on echocardiogram – medication does not cure or improve heart disease. It manages the symptoms. The main difference between hereditary DCM and non-hereditary DCM is the fact that patients with true nutritional (non-hereditary) DCM will recover when they are switched to another diet. This case also highlights the fact that the disease hasn’t ‘disappeared’ just because the FDA isn’t reporting on it, and is clearly linked to the grain free diet.
3. Coppinger LM, Freeman LM, Tyrrell WD Jr, et al. Echocardiographic and electrocardiographic findings in Irish Wolfhounds eating high-pulse or low-pulse diets. J Vet Intern Med. 2024; 38(3): 1300-1304. doi:10.1111/jvim.17075
In this study, VPCs [Ventricular Premature Contractions] were significantly more common in apparently healthy Irish Wolfhounds eating high-pulse diets compared with those eating low-pulse diets. This result is consistent with findings from a study of 188 dogs of 4 different breeds (Doberman Pinschers, Golden Retrievers, Miniature Schnauzers, and Whippets) eating diets with peas, lentils, or potatoes in the top 10 ingredients compared with those eating diets without those ingredients in the top 10 ingredients
While Irish Wolfhounds have a genetic predisposition to developing a unique form of hereditary DCM called ‘Irish Wolfhound Cardiomyopathy’, it was hypothesised that the patients fed the high pulse diets would develop arrythmias, larger left atrial and left ventricular measurements and lower fractional shortening, but echocardiographic measurements were not significantly different between the 2 diet groups – however the group fed high pulse did have more VPCs (a type of arrythmia) which indicates early cardiac changes.
So what?
This is only a handful of the studies that have been released over the past year on this topic, which at the very least should demonstrate that research into this condition and its link to grain free diets are very much alive. The FDA taking a step back and handing the torch over to academia hasn’t stopped scientists from trying to get to the bottom of it. But the real question is, what will you do with that information?
What I recommend you do…
- Feed a diet that follows the WSAVA Guidelines: the only diets that have never been implicated in nDCM are those that have been formulated by Board Certified Veterinary Nutritionists and undergone feeding trials to ensure their safety and efficacy.
- Food allergies in animals are usually to animal proteins, not grains: if you feel the need to exclude grains, feeding a hydrolysed diet that is designed for food elimination trials is your best bet (and these diets generally don’t contain grains anyway, but don’t replace them with peas/pulses/legumes)
- When we refer to grain free diets, this is really a catch all term and the terminology has evolved over time. I caution pet owners to also check ‘plant-based’ or ‘vegetarian’ diets which may also include high levels of peas, pulses and legumes
- If for some reason grains must be avoided (I’m yet to find a reason this is necessary), select a diet that does not contain what the FDA calls ‘suspect ingredients’ in the top 10 ingredients. These include peas, lentils, other legume seeds (pulses), and/or potatoes in various forms (whole, flour, protein, etc.)
I’m not the fun police, nor do I want to keep having to bring this up, but we really do need to set the record straight – just because the FDA stopped their investigation, does not mean grain free DCM was some farce invented by big pet food (despite what some people might have you think) or that its case closed and we have no more information than we started with.
Science is slow, but we have more than enough information to be cautious with our recommendations to safeguard our pet’s health. All I know, is I don’t ever want to have to have the heartbreaking conversation with another pet owner that their choice in pet food is what caused their pet’s illness.
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