Updated December 23, 2022
The U.S. Food and Drug Administration (FDA) continues its investigation into a potential link between certain diets and dilated cardiomyopathy (DCM) in dogs. This condition, affecting the heart, has raised concerns among pet owners and veterinarians, particularly in relation to “grain-free” dog foods. While the FDA is not issuing further public updates until significant new scientific information emerges, they remain committed to understanding this complex issue. As of November 1, 2022, the FDA has received numerous reports of DCM in dogs and is diligently reviewing them to identify any potential patterns or causes. It’s important to note that while these reports are valuable, they don’t, on their own, establish a definitive causal link between specific dog food brands and DCM. The FDA encourages ongoing research and collaboration within the scientific, veterinary, and pet food industry communities to further explore this matter.
Originally updated June 27, 2019
The FDA’s investigation began in July 2018 after an initial announcement regarding reports of DCM in dogs consuming certain pet foods. A common factor in many of these diets was the “grain-free” label and a high proportion of peas, lentils, other legume seeds (pulses), and/or potatoes listed as main ingredients. These ingredients often appeared within the first 10 ingredients on the ingredient list, before vitamins and minerals. Interestingly, many reported cases involved dog breeds not typically known to be genetically predisposed to DCM. The FDA’s Center for Veterinary Medicine (CVM) and the Veterinary Laboratory Investigation and Response Network (Vet-LIRN) are working together to delve deeper into this potential connection. Current data suggests that the relationship between diet and DCM in dogs is intricate and likely involves a combination of factors.
The FDA acknowledges the worries of pet owners, as DCM can be a severe and even fatal disease. Many reported cases are associated with “grain-free” dog food brands, prompting further scrutiny of these formulations. The FDA is employing various scientific methods to investigate the emergence of DCM and its possible dietary links.
This article serves as the FDA’s third public update on this investigation, following a previous update in February 2019, which covered investigative work through November 30, 2018.
Understanding the Scope: FDA’s Investigation into DCM Cases
On this page:
Reported DCM Cases to FDA
Dietary Information from DCM Cases
Product Testing Procedures
The Role of Taurine & Amino Acids
Vet-LIRN Diagnostic Testing Efforts
Collaborative Efforts in the Investigation
Guidance for Pet Owners and Veterinarians
Next Steps in the Investigation
Accessing Additional Information
Cases of DCM Reported to the FDA
For this investigation, the FDA defines a “case” as a reported illness in a dog or cat diagnosed with DCM. Many reports submitted to the FDA included extensive clinical details like echocardiogram results, veterinary records, and thorough diet histories. The statistics presented here include only cases where a veterinarian or veterinary cardiologist confirmed a DCM diagnosis. General cardiac reports without a DCM diagnosis were not included in these numbers, although this information remains valuable for identifying early heart changes that may precede symptomatic DCM. For more detailed technical information on reported cases, including those without a formal DCM diagnosis, refer to the Vet-LIRN DCM Investigative Update. While sporadic DCM reports were received as early as 2014, the majority came after the FDA’s public announcement in July 2018 about the potential link between diet and DCM.
Alt text: Trend of DCM Reports to FDA Over Years: 2014-2019. Chart displaying a significant increase in Dilated Cardiomyopathy reports to the FDA, particularly after 2018, highlighting rising concerns about dog food brands.
Between January 1, 2014, and April 30, 2019, the FDA received 524 DCM reports (515 canine, 9 feline). Approximately 222 of these were reported between December 1, 2018, and April 30, 2019 (219 canine, 3 feline). Some reports involved multiple affected animals from the same household. The following breakdown reflects the number of individual animals affected. The American Veterinary Medical Association estimates around 77 million pet dogs in the U.S. Most dogs eat pet food without developing DCM. The typical occurrence rate of DCM in dogs is unknown, but the increased reports to the FDA suggest a potential rise in cases in dogs without genetic predisposition.
Animal Statistics in DCM Reports (January 1, 2014 – April 30, 2019)
| Number of reports | Number of animals affected | Number of deaths | |
|---|---|---|---|
| Dogs | 515 | 560 | 119 |
| Cats* | 9 | 14 | 5 |
*Cats are more prone to hypertrophic cardiomyopathy, another form of heart disease.
DCM is known to be a genetic condition in dogs, particularly in large or giant breeds like Dobermans, Great Danes, and Irish Wolfhounds. It’s also seen in Cocker Spaniels linked to taurine deficiency and is considered less common in small and medium breeds. Underreporting of cases is suspected because symptomatic treatment is common, and diagnostic testing and treatment can be expensive and complex. The FDA has noted a reporting bias for breeds like Golden Retrievers due to breed-specific social media groups raising awareness and encouraging reports to the FDA. Because disease occurrence in dogs and cats isn’t routinely tracked by a widespread surveillance system like the CDC for human health, baselines for typical disease rates are limited to FDA reports.
Alt text: Top Dog Breeds in DCM Reports: Golden Retrievers Lead. Bar chart showcasing Golden Retrievers as the most reported breed in FDA Dilated Cardiomyopathy cases, followed by Mixed Breeds and Labrador Retrievers, indicating potential breed-specific vulnerabilities to certain dog food brands.
Breeds with more than one report include Afghan Hound, Australian Cattle Dog, Beagle, Belgian Tervueren, Border Collie, Boston Terrier, Bull Terrier, Chihuahua, Dalmatian, English Cocker Spaniel, English Springer Spaniel, Flat-coated Retriever, French Bulldog, Gordon Setter, Hound (unspecified), Irish Setter, Irish Soft-Coated Wheaten Terrier, Jack Russel Terrier, Maltese, Miniature Schnauzer, Old English Sheepdog, Pomeranian, Portuguese Water Dog, Pug, Retriever (unspecified), Rhodesian Ridgeback, Rottweiler, Rough-haired Collie, Saluki, Samoyed, Schnauzer (unspecified), Shepherd (unspecified), Staffordshire Bull Terrier, Standard Long-haired Dachschund, Vizsla, Whippet, and Yorkshire Terrier.
Genetic DCM often affects middle-aged to older male large and giant breed dogs. FDA CVM DCM cases span a wide range of breeds, ages, and weights, with a higher proportion of males, consistent with genetic forms. The significance of this is unclear but could indicate some cases are genetic, diet-related, or a combination.
Table 1: Average Age and Weight – DCM Cases in Dogs Reported to FDA-CVM
| Dogs | Mean | Range |
|---|---|---|
| Age (years) | 6.6 | 0.4-16 |
| Weight (lbs) | 67.8 | 4-212 |
Table 2: Average Age and Weight – DCM Cases in Cats Reported to FDA-CVM
| Cats | Mean | Range |
|---|---|---|
| Age (years) | 6 | 0.4-17 |
| Weight (lbs) | 10.7 | 7-13 |
Table 3: Sex Distribution in DCM Cases Reported to FDA-CVM by Species (%)
| Sex (% of cases) | Male | Female |
|---|---|---|
| Dogs | 58.7 | 41.3 |
| Cats | 62.5 | 37.5 |
Diet Information from DCM Cases
Most canine DCM reports involved dry dog food formulations, but raw, semi-moist, and wet foods were also represented.
Alt text: Dog Food Types in DCM Reports: Dry Food Predominant. Chart illustrating that dry dog food is the most common formulation reported in FDA Dilated Cardiomyopathy cases, while other types like raw and wet food are also represented but less frequently, suggesting a focus on dry dog food brands in the DCM investigation.
When considering the most frequently mentioned pet food brands in DCM reports, it’s important to note that the following graph is based on reports including brand information and that some reports listed multiple brands. Brands named ten or more times are highlighted below. For a detailed, case-by-case breakdown, see Canine Dilated Cardiomyopathy Complaints Submitted to FDA-CVM Through April 30, 2019. The FDA advises pet owners to consult with their veterinarians, potentially including a board-certified veterinary nutritionist, for tailored dietary advice before making any changes to their pet’s diet.
Alt text: Popular Dog Food Brands Linked to DCM Reports: Acana and Zignature Lead. Bar graph displaying Acana and Zignature as the most frequently named dog food brands in FDA Dilated Cardiomyopathy reports, followed by Taste of the Wild and 4Health, raising questions about ingredients used by these and similar dog food brands.
To better understand the diets in DCM cases, product labels were analyzed for “grain-free” status (absence of corn, soy, wheat, rice, barley, or other grains) and the presence of peas, lentils (including chickpeas and beans), or potatoes (including sweet potatoes). Due to the prevalence of peas and/or lentils, a “peas and/or lentils” category was created. Over 90% of products were “grain-free,” and 93% contained peas and/or lentils. Potatoes were present in a smaller proportion.
Alt text: Prevalence of Grain-Free and Legume Ingredients in DCM-Linked Dog Foods. Chart showing that over 90% of dog food diets reported in FDA Dilated Cardiomyopathy cases are grain-free and contain peas and/or lentils, highlighting a potential ingredient link in certain dog food brands.
Animal protein sources in reported diets varied widely, with many diets containing multiple sources. Chicken, lamb, and fish were most common, but some diets included less typical proteins like kangaroo, bison, or duck. No single animal protein source was dominant.
Alt text: Common Animal Proteins in DCM Dog Food Diets: Chicken, Lamb, and Salmon. Graph listing Chicken, Lamb, and Salmon as the most frequently reported animal protein sources in dog food diets associated with FDA Dilated Cardiomyopathy cases, indicating a wide variety of protein sources across different dog food brands.
Product Testing for Dog Food Brands
Prior to the July 2018 DCM Update, FDA/Vet-LIRN tested numerous products for minerals, metals (calcium, magnesium, phosphorus, iron, cobalt, copper, zinc, selenium, iodine), and amino acids (taurine, cysteine, methionine). These initial tests did not reveal any abnormalities.
Since the July 2018 update, Vet-LIRN has tested both “grain-free” and grain-containing products for:
- Protein, fat, moisture
- Crude fiber, total dietary fiber, soluble fiber, insoluble fiber
- Total starch, resistant starch
- Cystine, methionine, and taurine
The average percentages of protein, fat, total taurine, total cystine, total methionine, total methionine-cystine, and resistant starch on a dry matter basis were similar for both grain-free and grain-containing products. More details are available in the Vet-LIRN DCM Update.
Further food testing remains ongoing.
Taurine & Amino Acids in Dog Food and DCM
Nutritional research generally considers taurine a non-essential amino acid for dogs, as they can synthesize it from cysteine and methionine. Most grain-free products tested had methionine-cystine levels above the minimum nutritional requirement of 0.65% for adult dog maintenance food, as published by the Association of American Feed Control Officials (AAFCO).
The FDA is still actively investigating the potential role of taurine metabolism (absorption and excretion) in DCM cases. Understanding this aspect is crucial to determining if and how it connects to diet.
Diagnostic Testing by Vet-LIRN
Vet-LIRN has interviewed 95 owners of dogs and cats with DCM to gather detailed dietary histories and explore other potential contributing factors, such as environmental exposures like heavy metals or poisonous plants.
Vet-LIRN has also partnered with a network lab to collect biological samples (blood, urine, feces, DNA) from dogs without a known breed predisposition to DCM as a comparison group.
As of April 30, 2019, Vet-LIRN has reviewed 19 necropsy reports from dogs with suspected heart disease, including 13 necropsies coordinated from FDA Safety Reporting Portal cases. One additional necropsy is pending evaluation. These necropsies were conducted by veterinarians or veterinary pathologists, and Vet-LIRN is currently processing tissues for histopathology, to be reviewed by a board-certified veterinary pathologist.
Vet-LIRN is collaborating with Chesapeake Veterinary Cardiology Associates (CVCA) to collect comprehensive medical records, owner interviews, and diagnostic samples from pets diagnosed with DCM by a board-certified veterinary cardiologist via echocardiogram. These cases are part of the overall DCM case count but were selected for in-depth study due to their ongoing care and comprehensive documentation at CVCA.
Upon DCM diagnosis confirmation by CVCA, samples (blood, urine, feces, DNA swabs, and food – if the pet isn’t supplemented and is eating “grain-free” dog food) are collected. Vet-LIRN tests blood and urine for taurine, cystine, methionine, and other amino acids, and archives feces and DNA for potential future analyses.
CVCA repeats sample collection at 1-2 months and 6 months post-diagnosis, documenting any treatments or dietary changes. Repeat urine and blood samples are tested for amino acid content, and feces are archived. At the 6-month recheck, CVCA also conducts a repeat echocardiogram to assess heart changes. As of April 30, 2019, initial samples were collected from 14 dogs, and 1-2 month samples from 10 dogs. CVCA is currently collecting 6-month samples.
Of the initial 14 dogs, five were lost to follow-up, including 4 deaths, and will not complete the study. Vet-LIRN is evaluating heart histopathology for two deceased dogs. Initial and 1-2 month blood and urine samples from 14 and 10 dogs, respectively, have been tested and are under evaluation.
Vet-LIRN also collects food samples from each CVCA case and tests them for:
- Protein, fat, moisture
- Crude fiber, total dietary fiber, soluble fiber, insoluble fiber
- Total starch, resistant starch
- Free and total cystine, methionine, and taurine
Golden Retrievers and Taurine Deficiency
Research suggests Golden Retrievers may be genetically predisposed to taurine deficiency, a known DCM risk factor.
Veterinary cardiologist Dr. Joshua Stern at UC Davis is studying the DCM increase in Golden Retrievers, including a possible dietary link. Many DCM cases in Golden Retrievers are taurine-deficient. Owners of Golden Retrievers with suspected DCM should consult their veterinarian about checking taurine levels and considering an echocardiogram.
Collaboration in the DCM Investigation
In response to unprecedented events like the DCM issue, the FDA often collaborates with stakeholders across the animal health community to bridge knowledge gaps and advance investigations. These collaborations are crucial for a comprehensive understanding.
Veterinary Community Involvement
FDA veterinarians are working with the veterinary community to share information about DCM cases and identify the most valuable clinical data for the investigation. They are also consulting with board-certified veterinary cardiologists and nutritionists to learn more about case presentations and treatment responses.
Chesapeake Veterinary Cardiology Associates (CVCA) has provided comprehensive records for DCM cases to Vet-LIRN, including medical records, owner interviews, and diagnostic samples from pets diagnosed by board-certified cardiologists. These records include heart imaging, detailed dietary histories, diagnostic and treatment records, and case outcomes.
FDA veterinarians are collaborating with Drs. Lisa Freeman (Tufts University), Joshua Stern (UC Davis), and Darcy Adin (University of Florida) to learn from their research and case experiences. These experts co-authored a paper in the Journal of American Veterinary Medical Association in December 2018: “Diet-associated dilated cardiomyopathy in dogs: what do we know?“
Pet Owner Contributions
The FDA understands the distress caused by life-threatening diseases in pets. They express gratitude to pet owners who have participated in interviews and allowed veterinarians to share medical records and samples. The agency especially appreciates owners who provide tissues for analysis when a pet passes away. This information is vital for understanding cardiovascular changes related to diet.
Industry Partnerships
The recent surge in DCM cases is a recent phenomenon. The FDA is collaborating with the pet food industry to investigate potential changes in ingredients, sourcing, processing, or formulations that may contribute to DCM development. This includes examining various dog food brands and their manufacturing processes.
What You Can Do: Guidance for Pet Owners and Veterinarians
The FDA welcomes further collaboration and information to aid the investigation. Detailed instructions for reporting cases are available at “How to Report a Pet Food Complaint.”
Pet Owner Recommendations
If your dog shows potential DCM signs (decreased energy, cough, breathing difficulty, collapse), contact your veterinarian immediately. For severe symptoms and unavailability of your vet, seek emergency veterinary care. Your veterinarian may request a detailed dietary history, including all foods and treats consumed.
Veterinarian Guidance
CVM encourages veterinary professionals to report well-documented DCM cases in dogs suspected to be diet-related via the electronic Safety Reporting Portal. Comprehensive information, especially feeding history, medical records, and diagnostic testing details, is highly valuable. Detailed instructions are at “How to Report a Pet Food Complaint.” Technical veterinary information is available in the Vet-LIRN Update.
Industry Role
The FDA urges industry organizations and pet food manufacturers to contribute to the FDA’s investigation and conduct their own investigations to identify potential issues with formulas or ingredients used in various dog food brands.
What’s Next in the DCM Investigation
The FDA is continuing its investigation, gathering more information to determine if a specific dietary link to DCM exists, and will provide public updates as new information emerges regarding dog food brands and related factors.
