Dog Nutrition: What are Grain Free Diets and are they Safe?
Here’s what you’ll find in this article:
What a “grain free” diet is.
What dilated cardiomyopathy (DCM) is and its causes.
Why the FDA is looking into the potential association between particular diets and heart disease, and what they have found so far.
Three questions to ask your vet if your dog is experiencing symptoms of, or is diagnosed with, heart failure due to dilated cardiomyopathy.
What are Grain Free Diets & Why is everyone talking about them?
Grain free diets have gained significant popularity in the pet food marketing industry recently. As with several other human health trends, the “gluten-free” trend has seemed to take hold of the dog food industry as well. Of course, grain free and gluten free are not synonymous, but the relatedness of the idea has been heavily exploited by the pet food industry. As several humans turn to gluten free diets for various, sometimes non-medically approved/sound, reasons, many dog owners have started to turn towards grain free diet options for their pups as well. However, this may not be safe as human and dog physiology are quite different. As more and more options become available in the stores I wanted to look into the safety of these “grain free “ diets for myself and thus, for all of our readers! As always, I’m not a veterinarian, I’m just a passionate DogMa whose goal is to provide unbiased, evidence based information to other DogMa’s so they can feel confident making informed decisions for their special pup.
The term “Grain free” is not governed by regulatory agencies such as AAFCO or the NRC, so there is not a consistent single definition. Thus, each brand can adapt their recipes and make their own definition of “grain free.” However, the common theme of “grain free” diets is that they include a significantly higher proportion of multiple legumes, such as peas and lentils, other pulses (seeds of legumes), and potatoes which are used to replace grains such as corn, rice, barley, etc. (Freid, et al., 2020; Smith, et al., 2021). In addition, it is common for other sources of proteins, starches, and fiber derivatives to be used in these diets.
Each carbohydrate source has a unique nutritional composition and thus can affect the production process and use of the nutrients by the animal (Gizzarelli et al., 2021). For example, legumes (pea and lentil) are high in soluble dietary fiber and proteins compared to cereal grains (such as corn and rice). In addition, the amino acid profile (types of building blocks that make up proteins) vary depending on the source. In particular, legume protein is less rich in essential amino acids (the amino acids that a dog cannot make in its body and thus must consume in a food source) when compared to protein sources that were of animal origin (Gizzarelli, et al., 2021).
I use these examples not to bore you but to help you understand that there is more to the ingredients than simply whether they are “grain free” or not, and that when removing one source of nutrition it has to be replaced with another, which sometimes is one that may cause problems when consumed as a major proportion of a diet. This “other” ingredient, such as legumes and lentils in many grain free diets, is what has been speculated to be linked to the development of diet-associated DCM (Gizzarelli, 2021; Smith, et al., 2021) recently. However, I would also point out that the FDA is looking into several other potential causes such as exotic or alternate forms of proteins, although these investigations have not generated significant evidence suggesting their role as a cause of DCM.
Here are two examples of “grain-free” dog foods. One uses potatoes as its main way of supplementing for the lack of cereal grains while the other uses a “chickpea recipe” instead. P.S. Also notice the use of words like “Select” and “super premium” used as buzzwords to attract customers. Check out The Puppy DogMa’s post on …*** to learn more!
What is Dilated Cardiomyopathy and What Causes it?
In 2018 the FDA announced that they were investigating a link between diet and dilated cardiomyopathy in dogs. Dilated cardiomyopathy is a progressive, largely irreversible disease of the heart that causes it to not pump efficiently and effectively leading to heart failure overtime. Although the underlying cause of DCM is unknown, a genetic component has been identified. Previously, DCM was almost exclusively found in specific dog breeds, most notably large and giant breed dogs, including Great Danes, Boxers, Newfoundlands, Irish Wolfhounds, Saint Bernards, and Doberman Pinschers although it does occur in some small-medium dog breeds (American and English Cocker Spaniels) as well (FDA, 2018).
Besides the known genetic factor, DCM development has also been found in both dogs and cats with concomitant taurine deficiency (FDA, 2018). Taurine is an amino acid, a building block of proteins, needed for the body to function. Certain dog breeds are more susceptible to taurine deficiencies for reasons unknown but it has become common practice to check taurine levels if DCM is discovered, especially in nontraditional dog breeds (McCauley et al., 2020; FDA, 2018).
Why and What the FDA is investigating in relation to diet associated DCM:
The FDA released an announcement about the possible link between diets with high levels of legumes and potatoes (often labelled as “grain free”) and DCM in nontraditional breeds, that was NOT linked to taurine levels (FDA, 2018 & 2019). Further, a study done by Gizzarelli, et al. (2021) found that the source of carbohydrates and use of balanced diets did not significantly alter the levels of taurine in healthy adult dogs. This further supports the concern for a separate diet associated cause of DCM in dogs, unrelated to taurine levels. Thus, understanding the difference between genetic factors and diet is important as most cases of DCM due to genetic susceptibility are irreversible, while it has been found that DCM cases linked to diet may be reversible.
Following the announcement in July of 2018 the FDA has researched the possibility of diet-associated DCM thoroughly and provided updates along the way. Their investigation has included looking into dog food brands and components of the dog foods most cited in the case reports of DCM over several years. For the purpose of their studies they considered a product “grain free” when it did not contain corn, soy, rice, or barley. It was found that 90 % of the products most cited in reports were “grain free” and 93 % contained peas and/or lentils (a smaller proportion contained potatoes) (FDA, 2019). As of 2020, > 1100 dogs with DCM were reported to the FDA (only dogs with confirmed DCM by echocardiogram were included, there were likely many more that were simply treated symptomatically without formal diagnosis) (Smith, et al., 2021).
What is unique about dogs with diet-associated DCM is that there is often significant echocardiographic improvement and prolonged survival times post-diet change, which is in contrast to traditional genetically-associated DCM (Smith, et al., 2021). In a study by Freid et al., (2020) dogs diagnosed with DCM between 2014-2018 were split into groups, one group continued on their original grain free diet while another group was changed from a nontraditional (grain free) diet to a “traditional” diet. They found that the dogs that were changed from a nontraditional diet to a traditional diet had significantly improved cardiac function/parameters and longer survival times when compared to dogs that were kept on their nontraditional diets (Freid, et al., 2020).
What you should ask your vet if your dog is exhibiting signs of or is diagnosed with DCM:
What breed is my dog (includes higher incidence of DCM in mixed breeds that have components of high risk dog breeds such as Doberman Pinscher, etc.)
Has the Taurine level been checked?
Is your pup on a “grain-free,” nontraditional, or high legume/lentil diet?
These three questions cover the most common causes of dilated cardiomyopathy in dogs and should help you to feel better prepared to talk with your vet about potential diet changes and recommendations if needed. As always, when considering a specific diet for your pup it is always good to talk with your veterinarian about the options. I simply hope that by reading this you will feel more prepared to do so and feel confident in making decisions about your dog’s nutrition! Please send us any questions or comments you have on DCM, diets, or other aspects of dog nutrition at thedogmapack@gmail.com .
Furever yours,
The Puppy DogMa
References:
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
Freid, K. J., Freeman, L. M., Rush, J. E., Cunningham, S. M., Davis, M. S., Karlin, E. T., & Yang, V. K. (2021). Retrospective study of dilated cardiomyopathy in dogs. Journal of Veterinary Internal Medicine, 35(1), 58–67. https://doi.org/10.1111/jvim.15972
Gizzarelli, M., Calabrò, S., Vastolo, A., Molinaro, G., Balestrino, I., & Cutrignelli, M. I. (2021). Clinical Findings in Healthy Dogs Fed With Diets Characterized by Different Carbohydrates Sources. Frontiers in Veterinary Science, 8. https://doi.org/10.3389/fvets.2021.667318
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
Medicine, C. for V. (2018). FDA Investigating Potential Connection Between Diet and Cases of Canine Heart Disease. FDA. https://wayback.archive-it.org/7993/20201222194256/https://www.fda.gov/animal-veterinary/cvm-updates/fda-investigating-potential-connection-between-diet-and-cases-canine-heart-disease
Medicine, C. for V. (2019). Vet-LIRN Update on Investigation into Dilated Cardiomyopathy. FDA. https://www.fda.gov/animal-veterinary/science-research/vet-lirn-update-investigation-dilated-cardiomyopathy
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
Smith, C. E., Parnell, L. D., Lai, C.-Q., Rush, J. E., & Freeman, L. M. (2021). Investigation of diets associated with dilated cardiomyopathy in dogs using foodomics analysis. Scientific Reports, 11(15881). https://doi.org/10.1038/s41598-021-94464-2
