How Experts Evaluate Grain-Free and Gluten-Free Food

In July 2018, the FDA announced that it had begun investigating reports of canine dilated cardiomyopathy (DCM) in dogs eating certain pet foods, many labeled as "grain-free.” DCM typically affects larger and giant dog breeds, such as Doberman pinschers, boxers, Irish wolfhounds and Great Danes. In these breeds, DCM is thought to have a genetic component. However, recently reported cases of DCM have included dog breeds not previously known to have a genetic predisposition to the disease, such as miniature schnauzers and bulldogs.

To date, no research has identified grain-free dog food as a potential cause of DCM. The FDA’s Center for Veterinary Medicine (CVM) and the Veterinary Laboratory Investigation and Response Network (Vet-LIRN) continue to investigate the potential association between certain pet foods and DCM.  

As grain-free pet foods come under question, we at Tractor Supply want to provide our customers helpful resources as you navigate dog food options, looking for what’s best for your beloved pet. Read on as we explore the science behind DCM, as well as what exactly the results of the FDA’s findings mean for pet owners and their dogs. With input from veterinary experts Dr. Alexia Heldman, DVM, and Dr. Katryna Fleer, DVM, MPVM, we break down what you need to know when choosing what will fill your dog’s bowl.

The facts on grain-free dog food and DCM: Experts weigh in

Caring for our dogs is always a priority. That’s why we’re turning to the experts: We ask veterinarians about grain-free diets and what pet owners should know and look for when evaluating dog food choices.

Meet the pet food experts:

Dr. Alexia Heldman, DVM, has been the Director of Veterinary Affairs at Diamond Pet Foods for five years. Prior to that, she cared for pets in private practice and supported other veterinarians by helping them incorporate new pharmaceuticals, as they were launched, to advance pet health and decrease the incidence of preventable diseases.

Dr. Katryna Fleer, DVM, MPVM, is the Medical Director at VIP Pet Care. Over the last decade, as a researcher studying animal health and disease transmission, Dr. Fleer has worked with different species around the world, both in the wild and in zoos. She has also completed studies in broader public health issues concerning both humans and animals, and much of her work is used by government agencies to help solve public health issues.

Q: What are the issues pertaining to grain-free dog food and DCM, and what do dog owners need to know?

Dr. Heldman: Certain breeds have a genetic predilection to DCM. For example, in assessing Dobermans of all ages, 58% had signs of DCM, according to a study.

Grain-free foods have been on the market since the early 2000s, and no correlation between a grain-free diet and DCM was reported before now. Before changing diets, a pet owner should have a nutritional assessment of their dog’s diet [by a trusted veterinarian].

Q: How did grain-free dog food options come to be?

Dr. Heldman: Pet owners like to buy pet food with similar ingredients to their own diet. They want healthy and natural ingredients that are FDA-approved and with a sound nutritional profile.

Dr. Fleer: I graduated from veterinary school in 2007, and I remember that the grain-free push was just starting out and it was really interesting to see the new foods that were coming out. Part of it was because we were looking at dog allergies more and wondering, “What are these dogs allergic to?” And a lot of the nutritionists at that point were thinking [we could] eliminate some of these [gluten] allergies. But it turns out that dogs are also allergic to certain proteins and other [foods], so it's not as simple as just taking out grains.

I think we've learned a lot since then. We've grown as a profession and figured out that dogs are complicated, every dog is unique, and we need to figure out what's right for each particular dog.

Q: What exactly is the connection between grain-free dog food and DCM?

Dr. Heldman: To date, the FDA still has not found any science-based causes to link grain-free diets­–including Taste of the Wild or 4health­–to DCM. The underlying cause of DCM, besides genetic predilection, is still not known. Taurine deficiency is well-documented as potentially leading to DCM. For that reason, taurine has been added to our lamb-based recipes for years. 

Dr. Fleer: We are seeing not only a spike [in DCM cases], but in breeds that we wouldn't normally associate with DCM. You can look at the numbers; they’re not huge, but there were enough [cases] to alert the FDA to say, “This might be a problem, we need to think about it in the future.” So, the question is: What is the difference right now? Is it a food thing? Is it an environmental thing? Is it a new breed thing?

My current opinion is that we're still looking at this [issue], so let's wait and see what we find when we do more research. If your dog is currently on a [special] diet, it's probably OK to keep them on that, especially if they have some sort of condition that got them on the specific diet.

Q: Are all vets aligned with the FDA’s approach to investigating the link between DCM and grain-free foods?

Dr. Heldman: Not necessarily. The FDA’s statement left a lot of questions, not only for consumers but for veterinarians too. While we cannot speak for other veterinarians, we do know there are many differing opinions. 

Dr. Fleer: I talk to a lot of vets on a regular basis, and everybody I talk to is very interested, very up to date. I think what we're looking for right now [may not be] a definitive answer, but more of a better guideline on how to treat our pets appropriately.

Q: What are pet food makers doing to help shoppers find new healthy alternatives?

Dr. Heldman: [At Diamond,] all of our recipes and ingredients meet both the Association of American Feed Control Officials (AAFCO) guidelines and FDA standards, and are complete and balanced. Additionally, when nutritionally relevant, we add supplemental levels of methionine, taurine, and carnitine to formulations. That way, if a dog has a physiological problem making taurine or retaining it, additional taurine is being supplied from the food. We know that every dog is different with varying tastes and nutritional needs, which is why our original 4health formulas are a good option for those looking to feed their pets a grain-inclusive diet.

Glossary of dog food terms

Veterinary medical information and reports can be confusing. To help pet owners make the best decision for their dog’s unique health needs and palate, we are sharing some key definitions to know.

Dilated Cardiomyopathy (DCM): DCM is a serious disease of the heart muscle that causes the heart to beat at a weaker rate and to enlarge. DCM can result in abnormal heart rhythms, congestive heart failure (a build-up of fluid in the lungs or abdomen) or sudden death. In dogs, it typically occurs in large and giant breeds.

Grain-free dog food: Any dog food made without wheat, corn, rice or other grains is considered grain-free. These options may contain alternative sources of carbohydrates, such as potatoes in various forms (whole, flour, or protein), pea flour, peas, lentils and other legume seeds (pulses), as main ingredients.

Gluten allergy or grain sensitivity: In dogs, this very rare sensitivity is called gluten-sensitive enteropathy.

Gluten-free: Any dog foods or treats that exclude gluten-containing grains, such as wheat, barley and rye. They may include other grains, such as corn and rice. While some owners choose gluten-free dog food because their pet has been diagnosed with a medical condition that requires a gluten-free or grain-free diet, others do so out of personal preference.

Limited-ingredient dog food: As part of a simple ingredient approach, the recipe components you might find on a limited-ingredient list include real meat, poultry or fish, whole grains, egg and vegetables.

Meat-dominant dog food: Dog food in which animal protein is the dominant source of protein in the recipe. This can include various forms of chicken, tuna, salmon, cod, turkey, beef, lamb and buffalo.

Regular dog food: When we say, “regular dog food,” we simply mean dog food that contains grains. Dog food with grains may contain wheat, corn, barley, oats, rye, rice and soy, and it remains a popular choice among many owners.

Dog food label checklist

When choosing dog food, look for:

• Age, Breed and Size: What type of dog is the food intended for?
• AAFCO Certification: This is typically found on the back of the bag or can.
• Ingredient List: Know the main source of protein, as well as any potential allergens for your dog.
• Feeding Guidelines: These, along with guidance from your vet, can tell you how much and how often to feed your dog.

From understanding key ingredients to choosing between wet and dry, read more tips for finding the best food for your dog in this slideshow.

At Tractor Supply, we understand that dogs aren’t just pets–they’re family members. We’re committed to giving you the products and services that help you maintain your dog’s health and well-being throughout their life. That’s why many of our stores have PetVet clinics, which provide convenient access to high-quality pet wellness care. In addition, we offer competitive prices on many dog food brands for a range of breeds, dietary needs and preferences.

While there are varying views on grain-free diets for dogs, your trusted vet will always prioritize your pet’s health. If you have additional questions or if you suspect your dog has a food allergy or sensitivity, we recommend working with your vet to get answers. They can help you identify allergies and sensitivities and recommend a diet aimed at keeping your dog healthy and happy.