Another New Study Links DCM and Diet (Dec 2020)

Published in the Journal of Veterinary Internal Medicine, a retrospective analysis has again affirmed a link between certain diet types and dilated cardiomyopathy. Among the authors is Dr. Lisa Freeman, a veterinary nutritionist who has been closely working on this emerging issue since it was brought to public attention in 2018. This study was funded by Tufts' "Barkley Fund," established by the owners of a late Great Dane to further support and promote ever-improving care for dogs with heart disease. As a retrospective study, this paper has numerous limitations that the authors acknowledge. Furthermore, it does not establish a definitive causal relationship between diet and the development of DCM. Scientific establishment of such a causal relationship, if it exists, will require findings from the ongoing prospective studies that are occurring at multiple institutions. In the meantime, a correlation between diet types and DCM continues to be identified, warranting vigilance from the veterinary community, pet owners, and the pet food industry. 

The study is open access, meaning that anyone can read it online for free! You can use the hyperlink above to open it yourself. While the paper is accessible in terms of being free to read, the language of an academic paper can be intimidating for people outside of the field or profession. Here are the important highlights for pet owners and other concerned members of the public:

Methods & Sample:

• This study collected and analyzed records from dogs seen at the Tufts veterinary hospital by the cardiology or nutrition service and newly diagnosed with DCM between 2014 and 2018. 
• Dogs were grouped by traditional and non-traditional diet, as well as whether or not they changed diet following diagnosis
• Traditional diets (TD) were grain-inclusive extruded (kibble) diets that did not contain peas/lentils/potatoes in the to 10 ingredients and are produced by manufacturers that meet the WSAVA recommendations for selecting a pet food
• Non-traditional diets (NTD) were grain-free, contained peas/lentils/potatoes in the top 10 ingredients, or are not produced by manufacturers that meet the WSAVA recommendations for selecting a pet food
• 71 dogs were included
• 56 were eating NTD at time of diagnosis and 15 were eating TD
• 18 breeds were represented total

Findings:

• Among dogs eating non-traditional diets, those that changed diet had a significantly longer average survival time (337 days) than those that did not (215 days).
• Functional cardiac improvement was seen in dogs eating a NTD at time of diagnosis that switched to a TD. 
• The number of dogs diagnosed with DCM at this specific hospital has increased over time.

The authors close the paper: "Our results are consistent with the results of 2 previous studies suggesting that in dogs with DCM eating nontraditional diets, diet change can be associated with significant improvement in some echocardiographic measurements. In addition, dogs eating nontraditional diets that had their diets changed had a significantly longer survival time compared with those that did not have their diets changed. The underlying cause and mechanisms of diet‐associated DCM are still not understood, but our findings emphasize the importance of prospective studies to better understand this issue as soon as possible."