FDA Investigation into Heart Disease in Dogs: Where are we in September, 2020?

In July 2018, the United States Food and Drug Administration (FDA) announced its investigation focusing on grain-free dog foods that may possibly cause heart disease in dogs – specifically dilated cardiomyopathy (DCM). Approximately one year later, the FDA updated its findings by implicating 16 brands of grain-free dog food that were based on voluntary reported frequency, and then went radio silent. Remember that: voluntary reported frequency.

We, at Hemopet, wrote extensively on the subject and you can read our past posts here:

July 29, 2018: Dodds Responds to FDA Statement on Canine Heart Disease, Taurine Deficiency and Potential Dietary Causes

October 14, 2018: Articles Circulating about Heart Disease in Dogs

January 7, 2019: Dilated Cardiomyopathy (Heart Disease) in Dogs and Why Some Dogs Eat “Exotic” Ingredients

February 25, 2019: FDA Updates on Heart Disease in Dogs

July 8, 2019: Hemopet Responds to the FDA Implicating 16 Brands of Dog Food That May Cause Heart Disease in Dogs (provides a timeline of events)

We, too, went radio silent except for our blog post titled, “Dilated Cardiomyopathy in Dogs: Study on Protein Source” in September 2019. We went radio silent because the noise was deafening, and we wanted definitive answers from the FDA – not from the group of researchers who first loudly speculated without research documentation that grain-free and/or exotic ingredients were causing DCM in dogs.

So, where are we in September, 2020?

No one has heard from the FDA on the subject of DCM in dogs and possibly a connection to certain dog foods. Granted, SARS-CoV-2, the coronavirus that causes COVID-19, has possibly shifted the attention of the agency’s Center for Veterinary Medicine.

But now after alarming everyone 15 months ago, this situation is becoming ridiculous. We are now reading accounts from overwhelmed pet companion caregivers that were led to believe that grain-free dog foods were causing heart disease in their companion dogs.

We can no longer be silent as others continue to speculate and mislead the pet caregiver community.


First of all, DCM is complicated and possibly one of the biggest current mysteries in veterinary medicine. What we do know is that DCM can occur when an insufficient amount of the amino acids cysteine and methionine are ingested, which dogs use to synthesize taurine in the liver. Taurine is important as it prevents or slows the progression of DCM.

Regarding nutrition, no one knows for sure if it is a specific food ingredient, a group of foods or the interaction between foods. Of course, we need to factor into the equation breed disposition and genetics as well. There have been numerous studies completed with various combinations of proteins and grains, which we detail in several of our blog posts listed above.

In June 2019, it was reported at the AAVN Clinical Nutrition & Research Symposium that, “Although initially thought to be related to taurine, the majority of (DCM) cases reported to the FDA are not taurine-deficient.” The person – who had brought the national attention to this topic and then admitted this new finding – continued with caveats and personal findings.

Additionally, the FDA states on its investigation’s webpage, “Nearly all the grain-free products had methionine-cystine values above the minimum nutritional requirement of 0.65 percent for adult maintenance food for dogs published in the Association of American Feed Control Officials (AAFCO) Official Publication.”

The University of Illinois

Typically, grain-fee dog foods have high levels of peas, lentils, other legume seeds (pulses), and/or potatoes in various forms to replace the grains.

At the same symposium last year, researchers from the University of Illinois presented findings that we believe have been seriously overlooked.

  • 90-day, controlled study
  • 12 adult, female beagles
  • Randomly assigned to either a 45% green lentil diet or a poultry by‐product meal diet
  • Both diets met AAFCO standards
  • Results: no significant differences were found in taurine or amino acid concentrations between the two diets

Of course, that is just green lentils. As we stated before, no one knows if it is a specific food ingredient or the interaction of foods in the body. Remember all of the grain-free dog foods – from peas to potatoes – were lumped and implicated together prematurely.

Remember, again, the FDA is only gathering evidence of known cases of DCM in dogs. While this work is important, the agency is not gathering evidence of dogs not diagnosed with DCM and that are eating grain-free or exotic diets.

Industry Pushback

Companies and consortiums of grain-free food manufacturers have hired researchers to look into the question if their products are, in fact, contributing to increased incidents of DCM in dogs. Granted, their responses could reflect company bias. However, in this instance, we think it is worthwhile, as some of the researchers – who first brought the international attention to grain-free and “exotic” ingredients as possible causes of DCM without evidence to the forefront – had and have financial ties with major pet food companies.

In the links below, these researchers review and critique the studies that have been performed into the possible dietary and non-dietary causes of DCM in dogs.

Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation

Review of canine dilated cardiomyopathy in the wake of diet-associated concerns

Again, where are we in September of 2020?

We are nowhere closer to having the appropriate and correct answers. This is going to take some time.

Remember, if you’ve stopped feeding grains to your companion dog, think back to the many reasons why you stopped. It could be to prevent leaky gut syndrome, to help curb food sensitivities or intolerances to a particular grain, to maintain optimal weight in your dog, etc.

If you are worried, we understand. We suggest having your veterinarian take a blood sample to measure the methionine, cysteine and taurine levels in both whole blood and plasma, and send it to a diagnostic laboratory (University of California – Davis or University of Wisconsin) experienced with the appropriate reference ranges for circulating taurine. If the levels are lower than normal for dogs, please discuss the appropriate next steps with your veterinarian. Please send the information on your dog, including the food you are feeding, breed, health regarding DCM and retinal degradation, age and weight to the FDA. You and your dog would potentially be helping millions of other dogs.

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