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Diets and Heart Disease in Dogs

There has been a lot of media attention and many questions from worried pet-parents regarding the recent FDA report that suggests there is a connection between grain-free diets and the development of heart disease in dogs. Click here to see the article and click here to see a recent FDA update. The FDA has announced that there is a correlation between some diets and a certain type of heart disease called Dilated Cardiomyopathy (DCM) in dogs. Still, there is not enough information to say why or how this occurs. This blog post will go over some of the information currently available about diet-associated DCM.

What is Dilated Cardiomyopathy?
Dilated Cardiomyopathy (DCM) is a form of heart disease affecting the heart muscles of the lower chambers of the heart (the ventricles). The heart muscles weaken and do not contract normally, which leads to an enlargement of the ventricles (dilation). The inefficient pumping of blood caused by the dilation of the heart chambers leads to leaking of blood through the valves of the heart and the buildup of fluid in the body, which is called congestive heart failure (CHF). The left side of the heart is most commonly affected, which will cause fluid to build up in the lungs (pulmonary edema). The right side of the heart can also be affected, which means fluid will build up in the abdomen (ascites) and chest (pleural effusion). The signs of DCM depends on the severity of the disease and the breed of dog, but generally include decreased appetite, coughing, difficulty breathing, weakness, fainting, cardiac arrhythmias, and sometimes sudden death.

DCM can be hereditary, where a genetic mutation makes certain breeds more prone to developing heart disease. Medical treatment is required to alleviate symptoms of heart failure in these dogs, but there is no treatment that can reverse the condition. DCM can also be caused by nutritional deficiency. Some dog breeds are predisposed to taurine deficiency due to breed-specific metabolic abnormalities. Taurine is an amino acid that is required for proper heart function, which dogs can synthesize as long as they receive enough dietary cysteine and methionine, which are the “building blocks” for creating taurine. Taurine is not considered an essential amino acid for dogs, because they should be able to synthesize it from the building blocks they get from their diet.

If DCM is caused by a nutritional deficiency and is caught early enough, heart function can improve if treated with a change in their diet and medications.

What type of food is associated with cases of heart disease?
In 2017, veterinarians started reporting higher numbers of cases of DCM in dog breeds that were previously not associated with genetic DCM or a predisposition to taurine deficiency. It was noted that the majority of these dogs were eating the same brands of food or diets with similar ingredients. These patients usually recovered when their medical treatment was paired with a diet change, which leads to the ongoing investigation by the FDA. They found that most of these unusual cases were dogs that were eating BEG diets (BEG stands for Boutique companies, Exotic ingredients, and Grain-free). BEG diets generally containing high concentrations of pulses (a group of legumes including peas, lentils, chickpeas, and dry beans), potatoes, and other uncommon ingredients (such as kangaroo, duck, buffalo, lamb, bison, etc.). In addition to BEG diets, high fiber diets, low protein diets, vegetarian or vegan diets, and homemade diets were also found to be associated with cases of DCM.

At this point, more research is necessary to determine the exact link between DCM and what factors cause it. Many dogs with dietary related DCM have normal taurine levels in their blood, so it is clearly not a simple solution of “add taurine to the food”. Many of the diets follow and meet the guidelines set by AAFCO (Association of American Feed Control Officials). However, AAFCO does not regulate or test any pet foods. They provide nutritional recommendations for pet food companies to follow. Pet food companies should have a thorough understanding of how different ingredients and processing methods change the availability of the nutrients. Simply meeting nutritional recommendations doesn’t guarantee that the pet eating the diet will be able to digest and use all the nutrients they consume.

The trend towards BEG diets is not driven by science, but by consumer perception, which means some pet food companies will include ingredients without scientific evidence to back up those choices. There are many complex factors involved in understanding the nutritional links to DCM, and unfortunately, there are no concrete answers as to why certain diets can follow nutritional guidelines and still create taurine deficiency symptoms. Legumes have a very different amino acid composition than cereal grains, so making a simple substitution will create a deficit in some essential amino acids (such as methionine, which is necessary for taurine synthesis). Changing the ingredients also changes the type and amount of fiber in the diet, which impacts the way the nutrients are metabolized. Exotic meat sources will also have different nutrient profiles and availability than common meat ingredients, and they may impact the digestibility of other nutrients. Even the microbes in the intestines are influenced by dietary components and can play a role in how nutrients are digested. Creating a diet is not as simple as having “good quality ingredients” because animals have nutrient requirements, not ingredient requirements. It doesn’t do our pets any good to be eating expensive ingredients if they are not capable of extracting the necessary nutrients from it. What can pet owners do?

It’s important to note that not all BEG diets are to blame for this increase in DCM case. There are therapeutic diets that are grain-free or have a novel protein source that has not been associated with any cases of DCM and is very helpful for dogs with allergies or food intolerances. However, if your pet is on a BEG diet and does not have a medical reason to be, it may be worth considering a diet change. If your pet is on a BEG diet and showing any signs of DCM as discussed above, please contact your veterinarian right away.

Pet parents love their furry family members and want to do what’s right for them, but it can be difficult to know what that means when there is so much misleading information available. There are many unknowns with regards to the FDA report, which understandably increases clients’ concerns about what food they should be feeding their pets. If you have any questions or concerns regarding the food you are feeding your pet we recommend a conversation with your veterinarian to gain their advice as part of a regular check-up. Our veterinarians are here to help guide you on the nutritional options available and recommend those best suited for your pet.

Written by: Alicia Naundorf, RVT

Sources:

  1. “Diets and Heart Disease in Dogs and Cats” https://veterinarypartner.vin.com/default.aspx?pid=19239&id=8989590
  2. “Dilated Cardiomyopathy in Dogs and Cats” https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952598
  3. “Diet-associated dilated cardiomyopathy in dogs: what do we know?” Freeman, Lisa M., Joshua A. Stern, Ryan Fries, Darcy B. Adin, and John E. Rush. https://avmajournals.avma.org/doi/pdf/10.2460/javma.253.11.1390
  4. “Special topic: The association between pulse ingredients and canine dilated cardiomyopathy: addressing the knowledge gaps before establishing causation.”
  5. Mansilla, Wilfredo D., Christopher P.F. Marinangeli, Kari J. Ekenstedt, Jennifer A. Larsen, Greg Aldrich, Daniel A. Columbus, Lynn Weber, Sarah K. Abood, and Anna K. Shoveller. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396252/pdf/sky488.pdf
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Diets and Heart Disease in Dogs

There has been a lot of media attention and many questions from worried pet-parents regarding the recent FDA report that suggests there is a connection between grain-free diets and the development of heart disease in dogs.

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