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Is Grain-Free Dog Food Bad for Dogs?

My Lab and my weimaraner eat a dog food that is considered “grain free.”

I believe a grain-free diet for dogs makes sense, but I still worry a bit. I remember the headlines from 2018 about grain-free diets potentially causing heart disease in dogs.

So I decided to look into this a bit further for my own reassurance. Hopefully, this will also help you decide if a grain-free diet is right for your dog. 

Use this as part of your own ongoing research to help make the best decision for your own unique dog.

What is grain-free dog food?

Grain-free dog food is any type of food for dogs that is made without any grains (such as corn, wheat, barley, rye or rice). There are grain-free dry, canned, raw, freeze-dried and dehydrated dog foods. 

“Grain-free” does not mean “carb free.” Most grain-free diets provide carbohydrates for dogs through other sources such as potatoes, sweet potatoes, peas or lentils.

I remember when “grain free” diets became popular for pets in the 2010s. This was also a time when low-carb, paleo, “caveman” and keto diets were starting to get popular for average people.

Most dog food companies jumped on the “grain free” trend and offered a grain-free option in addition to their regular options. Unfortunately, some companies did so as a way to increase their sales and not necessarily to make a healthier option.

Nearly every dog and cat food brand came out with a grain-free option around 2010. Most companies still offer a couple of grain-free options.

Grain-free dog food and the potential link to heart disease

In 2018 the FDA said on its website that it had started investigating reports of canine dilated cardiomyopathy (DCM) in dogs eating pet foods labeled as “grain free.” DCM is a form of heart disease in dogs.

There was a lot of fear mongering during that time. Various news sites and blogs tried to scare pet owners using click-bait headlines. They seemed to suggest a grain-free diet will kill your dog, which is not the case.

The FDA never said there was a confirmed link between grain-free foods and heart issues in dogs. It was simply sharing “reports” from consumers that listed their dog’s breed and what the dogs were eating when diagnosed with DCM.

Over about a nine-year period from January 2014 through November 2022 the FDA received 1,382 reports of DCM in dogs, according to its website.

That’s an average of 153 reports per year. Although, the majority of reports were between 2018 and 2020. This is when the FDA issued a couple of public updates on the potential link between grain-free diets for dogs and heart disease.

Because the FDA’s updates were focused on grain-free dog foods and not dog foods as a whole, people feeding grain-free diets were more likely to be aware of these reports and send in their own report.

What is Canine Dilated Cardiomyopathy?

Canine dilated cardiomyopathy (DCM) is a disease that decreases the heart’s ability to generate enough pressure to pump blood through the vascular system, according to Cornell University College of Veterinary Medicine.

The college says on its website that the cause of canine DCM is not certain but “nutritional, infections and genetic predisposition” all seem to be factors. It is more common in certain breeds such as Dobermans, great danes, boxers and cocker spaniels.

Historically, DCM has been linked to a genetic predisposition in certain breeds such as the ones listed above, according to the FDA’s website. It appears there are also non-hereditary forms of DCM in dogs that may be affected by several factors such as underlying medical conditions, diet and genetics.

What are the signs of DCM in dogs?

Your dog may not show any signs of DCM early in the process, according to Washington State University’s College of Veterinary Medicine. The dog might show signs of reduced exercise tolerance. 

As the heart’s pumping ability worsens, blood pressure starts to increase in the veins behind one or both sides of the heart, according to the college. Lung congestion may develop and fluid may accumulate in the abdomen, indicating heart failure.

Is grain-free dog food bad for dogs?

Is grain-free dog food bad for dogs

We don’t know. 

There are about 1,300 reports to the FDA of canine DCM in dogs eating pet foods labeled as “grain free.” This is enough of a concern for some dog owners to avoid feeding grain-free diets.

On the other hand, there are no studies that prove grain-free diets are harmful to dogs. Thousands of dogs are eating grain-free diets with no known issues.

What do veterinarians say? Is grain-free dog food bad for dogs?

I emailed several veterinarians and asked them, is grain-free dog food bad for dogs?

They do not have a clear answer and their general opinions are similar to how I believe most pet owners feel about grain-free diets. We don’t know enough right now so it’s OK to be cautious. 

Dr. Cheri Honnas is the veterinary advisor to Bone Voyage Dog Rescue. This rescue helps street dogs in Mexico find homes in the U.S. and Canada.

She said that there is a notable correlation between grain-free, legume-rich dog diets and DCM in dogs but “more comprehensive studies are needed to definitively prove causation.”

Some of the vets I emailed recommend feeding most dogs a food that contains grains since there are so many options to choose from. While a few dogs do have allergies to grains, most do not, they said.

Other vets said it’s OK to continue feeding grain-free foods if it’s going well for your dog. 

They all said this issue is complex, and we need more research on this topic.

More research on grain-free diets and dogs

The FDA said on its website that it has called on the veterinary and academic communities to contribute research on various aspects of non-hereditary DCM in dogs. 

Many people from these groups participated in a scientific forum at Kansas State University in September 2020 and publicly shared their summaries or presentations. You can view them here.

Dogs that recovered from DCM with diet change

FDA scientists also presented at the KSU symposium on a group of 107 dogs that had fully or partially recovered from DCM with diet change and veterinary care. Twenty three of the dogs fully recovered and 84 dogs were partially recovered. You can see a 30-page pdf of their report here.

The scientists looked at the ingredients lists of what the dogs were eating at the time of diagnosis and compared that to the diets the dogs were switched to leading to a partial or full recovery.

Before diagnosis, 90% of the 107 dogs were eating foods labeled as “grain free.” Ninety four percent of their diets listed peas or lentils in the top four ingredients.

There was no animal protein that stood out as dominant in their diets, and 28% of the diets listed potatoes or sweet potatoes in the ingredients.

Twenty three of the dogs had a full recovery after a diet change. Ninety six percent of those dogs switched to a diet containing grains. Only 8 percent of the dogs switched to a food with peas listed in the top four ingredients.

Obviously, this is a very, very small group of dogs, but it is one of the reasons people began questioning diets that use peas for protein, especially foods with peas in the top four ingredients.

Are peas and lentils bad for dogs?

No. There is no evidence that peas and lentils are bad for dogs and both have been used in pet foods for many years with no evidence that they are dangerous, according to the FDA.

However, most of the reports that FDA has received on dogs with non-hereditary DCM were eating diets with peas or lentils high on the ingredients list, meaning the diets used them in greater proportion.

2023 University of Guelph study on grain free diets

The University of Guelph in Ontario, Canada, released a small study in 2023 using 28 Siberian huskies. The dogs were fed a balanced diet that contained up to 45 percent “whole pulse” ingredients (peas, lentils and beans) and no grains for 20 weeks.

The dogs were randomly divided into four groups and were fed diets with either 0%, 15%, 30% or 45% pulse ingredients. After 20 weeks, the study showed no change in cardiac function for any of the dogs.

You can read more on the study in the Journal of Nutrition here.

Of course, this is just one small study but it is interesting to see that these dogs did not seem affected at all by a grain-free diet high in pulse ingredients.

Grain-free diets and taurine deficiency

Taurine is an amino acid in meat that helps a dog’s organs to function properly.

One idea is that the higher amount of peas and lentils found in some grain-free diets are negatively interfering with a dog’s taurine levels. This is just one theory that still needs a lot of research. 

If you feed your dog a grain-free diet and you are concerned about his taurine levels, you can have your vet check this through a blood test. I plan to ask our vet about this the next time my dogs go in for a wellness exam.

Should you feed your dog grain free?

We all have to make the best decisions we can for our own dogs. No one has a clear answer on this, and I recommend you do your own research and talk with your dog’s vet about the best diet for your specific dog.

The veterinarians I emailed generally said if you decide to feed a grain-free diet, do so with caution.

“Not all grain-free diets may be problematic, but it’s beneficial to consult with veterinary experts and opt for dog foods backed by thorough research,” Honnas said.

Rotate what foods you feed your dog

One thing you can do to help your dog get a variety of nutrients over his life is to rotate which foods you give him. You could rotate between a few different brands or a few different flavors within the same brand.

Just remember to introduce new foods slowly, especially if your dog has a sensitive stomach. I always mix the new food in with the old food for a few days whenever I transition my dogs to a different food.

After learning more about the potential risks of grain-free diets, I plan to rotate my dogs between a grain-free food and a food containing grains. That way they will get more variety in their diets.

What is the FDA’s current position on grain-free diets for dogs?

On Dec. 23, 2022, the FDA said it does not intend to release further public updates on the link between grain-free diets and DCM in dogs “until there is meaningful new scientific information to share.”

There has not been an update since.

Prior to that was its June 2019 update which said it had started investigating reports of DCM in dogs eating “grain-free” foods. Often, these foods had a high proportion of peas, lentils, other legume seeds or potatoes as main ingredients.

How I plan to feed my dogs a grain-free diet

After reading all I could about grain-free diets for dogs, I am comfortable continuing to feed my own dogs a grain-free diet. But, I plan to rotate it with a food containing grains so they get a wider variety of nutrients. 

If you have specific concerns with your dog’s diet, you should discuss them with your dog’s veterinarian.

It’s unfortunate we don’t have more information on this issue at this time. In the next few years I’m sure we will start to get more answers as more research comes out.

Is a grain-free diet right for your dog?

Let me know your thoughts in the comments.


Wednesday 27th of September 2023

The FDA still hasn’t figured out why jerky was killing dogs, hmmm makes me wonder. And why would anyone think the lentils etc is natural for a carnivore to eat? The farther away from the ancestral diet the worse dogs lives will be.


Wednesday 27th of September 2023

Grain-free dry messed with my dog's urine pH which lead to crystals, inflammation, and bloody urine. I don't know for sure if it was that the dry food was grain free or the ingredient composition the food. He's never had an issue with raw so I imagine it was something else. Either way, I no longer give him grain free dry food.