Canine dilated cardiomyopathy (DCM) is a mostly genetic disease of the heart that results in a decreased ability of the heart to generate pressure to pump blood through the body. As the disease progresses the heart chambers become enlarged, and signs of heart failure can develop.
In July 2018, the American FDA first alerted pet owners to a POTENTIAL connection between dogs being fed grain-fee diets and DCM. This small statement caused a panic among pet owners (and dog food manufacturers!), many of whom had turned to grain-free diets due to allergies, sensitives, or the belief that they were healthier for their four-legged best friends. All of a sudden, they were doubting everything they had heard over the past decade about the benefits of grain-free food for dogs.
We noticed that the number of cases was low. In fact, it’s MUCH LESS THAN THE NUMBER OF DOGS SUFFERING FROM ALLERGIES DUE TO GRAINS! It was literally one in a million dogs that was contracting DCM from what was believed to be a non-hereditary source. (Before this, DCM was actually considered a primarily inherited disease).
Other issues with the connection included all the variables, between the dogs and also the foods they were fed. Each brand had a different formula.
In the end, on June 27, 2019, the American FDA posted their last update on the subject. They concluded: “Based on the data collected and analysed thus far, the agency believes that the potential association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors.”
Now, a year later, Sydney R McCauley, Stephanie D Clark, Bradley W Quest, Renee M Streeter and Eva M Oxford published their conclusive research on the subject in the Journal of Animal Science, June 2020. The team looked at each variable separately, including genetics, hypothyroidism, myocarditis, chronic tachycardia and known dietary deficiencies. They looked at all the information from the past two years, including all the vet records for the dogs that supposedly had DCM from grain-free diets. This is what they found:
Recently, a correlation between diets with specific characteristics, such as, but not limited to, containing legumes, grain-free, novel protein sources and ingredients, and smaller manufactured brands to DCM has come under scrutiny by academic researchers and the FDA. The use of the acronym “BEG” (boutique manufacturers, exotic proteins, and grain-free diets) and its association with DCM are without merit because there is no definitive evidence in the literature. At this time, information distributed to the veterinary community and the general public has been abbreviated synopses of case studies, with multiple variables and treatments, incomplete medical information, and conflicting medical data and opinions from veterinary nutrition influencers. Also, in past literature, sampling bias, overrepresentation of subgroups, and confounding variables in the data weaken this hypothesis. Additionally, based on current literature, the incidence of DCM in the overall dog population is estimated to be between 0.5% and 1.3% in the United States. However, the FDA case numbers (560 dogs) are well below the estimated prevalence. Therefore, it is impossible to draw any definitive conclusions, in these cases, linking specific diets or specific ingredients to DCM. (Journal of Animal Science, Volume 98, Issue 6, June 2020, skaa155)
Their work included reviewing over 150 studies on the causes of DCM. They could find no correlation between grain-free diets and DCM. They pointed out that the American FDA reports left out vital information, including a dog’s diet history (how long he had been on grain-free, as an example), age, overall health, etc., making impossible to draw conclusive correlations based off of it. The researchers concluded with this: “While determining the cause of recently reported cases of cardiac disease is of the utmost importance, based on this review of the current literature, there is no definitive relationship these implicated diet characteristics and DCM.”
While there is definitely room to learn more about DCM and what causes it, including if there are any dietary correlations, at this time there is no reason to suspect grain-free diets as a culprit, and as mentioned above, there are many more dogs with allergies and sensitivities to grain that make being on a grain-free diet paramount to their health and happiness. So, stay on your grain-free diet knowing you are giving your dog what is best for them to live a happy, healthy life.
Should there be any more research on the correlation between DCM and diets, we will continue to update you.