Understanding the DCM Research on Dog Nutrition
Over the past several years, many dog owners have heard concerns about a possible connection between certain diets—particularly grain-free foods—and a heart condition called Dilated Cardiomyopathy (DCM). This page gathers research and resources to help pet owners better understand the discussion.
What Is Dilated Cardiomyopathy (DCM)?
Dilated cardiomyopathy (DCM) is a serious heart condition in dogs where the heart muscle becomes weakened and enlarged. As the heart chambers expand and the walls thin, the heart cannot pump blood efficiently.
- Enlargement of the heart chambers
- Irregular heart rhythms
- Congestive heart failure
- Collapse or sudden death in severe cases
DCM has long been recognized as a primarily genetic condition, particularly in certain large and giant breeds such as Doberman Pinschers, Great Danes, Boxers, and Irish Wolfhounds.
Why Did Diet Become Part of the Conversation?
In 2018, the U.S. Food and Drug Administration (FDA) began investigating reports of DCM in dogs eating a variety of diets. Some early reports suggested certain diets—often described as “boutique, exotic, or grain-free” diets—might be associated with the condition.
This prompted a large amount of new research examining pet food ingredients, nutrient levels, manufacturing practices, and possible dietary risk factors.
What the FDA Investigation Found
After several years of investigation, the FDA released an update in December 2022 stating that there was insufficient evidence to establish a causal relationship between specific diets and DCM.
Reports of non-hereditary DCM were associated with both grain-free and grain-containing diets. Many of the diets referenced in reports included legumes or pulses such as peas or lentils high in the ingredient list. These ingredients have been used in pet foods for many years and are not considered inherently unsafe.
Peer-Reviewed Review of DCM Research
Veterinarians, veterinary cardiologists, and animal nutritionists from BSM Partners published a peer-reviewed literature review in the Journal of Animal Science examining more than 150 scientific studies related to dilated cardiomyopathy in dogs.
Following this extensive review, the authors reported that existing research does not support a definitive relationship between grain-free or legume-rich diets and DCM.
“We believe that further research is needed in order to reach sound conclusions with respect to the relationship between diet and DCM,” said Dr. Eva Oxford, a veterinary cardiologist and coauthor of the article. “This is why BSM Partners has initiated multiple original research projects that will shed additional light on this topic.”
Researchers also noted that many of the cases referenced in early FDA reports contained incomplete information, making it difficult to draw reliable conclusions. In many instances, important details such as a dog’s full diet history, age, or the presence of concurrent health conditions were missing.
Additionally, some reported cases involved dog breeds already known to have a genetic predisposition to DCM, which further complicates attempts to attribute the condition to diet alone.
What Current Research Shows
Prospective Diet Cardiology Study
- 7-month feeding study
- 65 dogs evaluated
- Included echocardiograms and cardiac biomarkers
- No significant differences between grain-free and grain-inclusive diets
DCM Incidence Study (2000-2019)
- National veterinary cardiology data review
- DCM incidence remained stable
- Grain-free food sales increased dramatically during the same time
- No clear correlation observed
Journal of Animal Science Review
- Comprehensive review of published research
- Examined decades of literature
- No definitive link between grain-free diets and DCM established
University of Guelph Diet Study
- Controlled feeding study in dogs
- Compared grain-free and grain-inclusive diets
- No differences in cardiac measurements or biomarkers
18-Month Diet Study (Hill's / Morris Animal Foundation)
- Long-term feeding study evaluating grain-free and grain-inclusive diets
- Included diets containing peas, pea fiber, and potatoes
- No significant changes in cardiac biomarkers
- No meaningful changes in taurine concentrations
- No clinical evidence of DCM observed
Industry Discussion
The discussion around diet and dilated cardiomyopathy has generated significant debate within the veterinary and pet nutrition communities.
Some industry reporting and legal filings have raised questions about how early DCM reports were interpreted and communicated to veterinarians and pet owners. Many have concern that the instigation and handling of the DCM scare may be more about profit than pet’s health.
In 2024, a lawsuit was filed alleging that certain individuals, funded by major players like Hill's, Nestle Purina, and the Morris Foundation among others, intentionally promoted concerns about grain-free diets and canine heart disease for profit and to spread misinformation, with the early research on the topic quickly being discredited as bad science.
Conclusion
After 18 months, no significant changes in cardiac biomarkers were noted in dogs fed grain-free foods or grain-inclusive foods with or without peas, pea fibers, and potatoes.
All evaluated foods appeared to have little to no impact on taurine concentrations or taurine excretion.
No dogs showed any clinical evidence of DCM on echocardiograms, although the onset of chronic degenerative valve disease was noted in several dogs, which was expected given its increasing prevalence in aging dogs.
Future research is needed to identify alternative variables and mechanisms that may influence the development and progression of DCM and to better understand the role of nutrition and the microbiome in cardiac health.