Grain-free Diets: A Possible Heartache for Man's Best Friend

By Camila Gutierrez



Food. It runs our lives from the moment we wake up to when we go to sleep. We are constantly reminded of how our diet is intricately woven into our daily lives and overall health. For this reason, wouldn’t we want the best food for our four-legged friends?


Nowadays, there is what feels like an endless array of choices of food for our beloved pets, specifically dogs. We hear all sorts of recommendations for what we should be feeding them: beef-based, fish-based, low-fat, age oriented, and the list goes on. The most recent craze, however, has been grain-free dog food. Although companies claim this specific diet improves a dog’s coat and keeps food allergies at bay, research has shown otherwise. This seemingly harmless diet is being investigated for its possible contribution to a recent spike in heart disease among dogs.


Imagine the heart as a balloon, constantly inflating and deflating, pumping blood throughout the body. The thick texture of the balloon allows it to return to its original shape after being blown up. If the balloon were thinned, its ability to pump air in and out would be weakened. This specific condition is referred to as dilated cardiomyopathy (DCM). The heart becomes larger and weaker, as its muscular ventricular walls thin (Fig. 1). Depending on the severity of the case, secondary effects of DCM can range from lethargy and unintentional muscle loss (cardiac cachexia) to severe respiratory problems and lethal cardiac arrhythmias (abnormal heartbeat).


Diagram depicting the heart with dilated chambers and decreased ability to pump blood. (Credit: Texas A&M University College of Veterinary Medicine & Biomedical Sciences)


Cases of this heart disease over the past five years were gathered from veterinarians across the country and sorted based on the diet of the dog diagnosed. A little more than a year ago, the FDA released a report that they had found a potential link between DCM and dogs being fed grain-free diets mainly composed of peas, lentils, and potatoes that must be investigated further. Prior to this, people believed that this dangerous and often lethal heart disease could only appear in dogs with low levels of taurine. This sulfur-containing amino acid is not considered nutritionally essential in canines, but it plays an important role in their central nervous and cardiovascular system. High levels of it are found within the myocardium, muscular heart tissue, and its various functions range from bile acid activator to cardiac function antioxidant. Breeds such as Golden Retrievers and Cocker Spaniels had been discovered to be more susceptible to this taurine deficiency and subsequently DCM, but the dietary link remained hazy. In a study conducted by the University of Illinois, twenty three of twenty four golden retrievers within the group known to have both taurine deficiency and DCM were being fed grain-free or legume-based diets. Although after analyzing more than 500 cases of DCM, the FDA has concluded that even dogs without a taurine deficiency can have this heart disease.


A retrospective analysis done over three years by veterinarians at NC State on forty eight dogs with DCM further supports this emerging dietary link. They found that out of the forty eight dogs with this heart disease, all those being fed grain-free diets had a larger diastolic left ventricular size than the other dogs. Now, the prospect of dietary components, such as grain-free food ingredients, being an alternate cause for DCM is being investigated more in depth to understand their exact relationship. Some veterinary cardiologists are choosing to recommend their clients switch off of these types of specific diets out of extreme precaution Although, it is still crucial to assess the limitations and confounding variables studies like these may possess. The FDA may inadvertently be creating sampling bias by only asking the public for additional information on dogs fed the specific diets being investigated. This could ultimately alter results.


Nevertheless, this research lays the foundation for studies into how diets may play an intricate role among other factors, such as genetic predisposition, linked to heart diseases. It is essential to consider the significance studies such as this one could have when related back to humans. The valuable information gathered can serve as further support for investigations regarding nutritional balances affecting human organ health over time and shed light on the multifactorial etiology of diseases.


With this knowledge, we will be able to efficiently diagnose and even prevent a wide range of debilitating organ diseases. With it, we can better not just the lives of man’s best friend, but mankind itself.

References

  1. Adin, D., DeFrancesco, T. C., Keene, B., Tou, S., Meurs, K., Atkins, C., Aona, B., Kurtz, K., Barron, L., & Saker, K. (2019). Echocardiographic phenotype of canine dilated cardiomyopathy differs based on diet type. Journal of Veterinary Cardiology, 21, 1–9. https://doi.org/10.1016/j.jvc.2018.11.002

  2. Canine Dilated Cardiomyopathy (DCM). (2017, December 13). Cornell University College of Veterinary Medicine. https://www.vet.cornell.edu/hospitals/companion-animal-hospital/cardiology/canine-dilated-cardiomyopathy-dcm

  3. Freeman, L. M., Stern, J. A., Fries, R., Adin, D. B., & Rush, J. E. (2018). Diet-associated dilated cardiomyopathy in dogs: What do we know? Journal of the American Veterinary Medical Association, 253(11), 1390–1394. https://doi.org/10.2460/javma.253.11.1390

  4. Kaplan, J. L., Stern, J. A., Fascetti, A. J., Larsen, J. A., Skolnik, H., Peddle, G. D., Kienle, R. D., Waxman, A., Cocchiaro, M., Gunther-Harrington, C. T., Klose, T., LaFauci, K., Lefbom, B., Lamy, M. M., Malakoff, R., Nishimura, S., Oldach, M., Rosenthal, S., Stauthammer, C., … Ontiveros, E. (2018). Taurine deficiency and dilated cardiomyopathy in golden retrievers fed commercial diets. PLOS ONE, 13(12), e0209112. https://doi.org/10.1371/journal.pone.0209112

  5. McCauley, S. R., Clark, S. D., Quest, B. W., Streeter, R. M., & Oxford, E. M. (2020). Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. Journal of Animal Science, 98(6). https://doi.org/10.1093/jas/skaa155

  6. Medicine, C. for V. (2020). FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy. FDA. https://www.fda.gov/animal-veterinary/outbreaks-and-advisories/fda-investigation-potential-link-between-certain-diets-and-canine-dilated-cardiomyopathy

  7. Pezzali, J. G., Acuff, H. L., Henry, W., Alexander, C., Swanson, K. S., & Aldrich, C. G. (2020). Effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Journal of Animal Science, 98(2). https://doi.org/10.1093/jas/skaa010

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