Popular Grain-Free Pet Diets Linked To Heart Disease

Popular brands of grain free food such as Blue Buffalo, Natural Balance and Merrick have been associated with the development of heart disease in dogs. Read on for information on what to do if you have been feeding your dog grain-free.

STRAIGHT TO THE POINT: Popular grain-free diets have been linked to the development of dilated cardiomyopathy, a potentially life-threatening heart disease in dogs. If you are currently feeding a grain-free diet talk to your veterinarian about the risks and consider transitioning your furry friend to a grain-included formula. 

Grain-Free Diets Linked to Heart Disease in Dogs


This is big.

Not just a little bigger than usual.

The FDA currently released its third status report on the link between grain-free dog food and a type of heart disease known as Dilated Cardiomyopathy (DCM). In this statement, they provided specific case information that implicates both categories of foods and specific brands in the development of potentially life threatening DCM. If you currently feed your dog a grain-free diet, it is time to transition to a grain-included diet.

What is a Grain Free Diet

The claim of ‘grain-free’ has been a trend in pet food for the past 10 or 20 years, being especially prevalent in the high end boutique brand. On a whim, I recently took a trip to my local pet food stores to see how many brands of dog food advertised ‘grain-free.’ In the highest price point aisle, every single brand currently had a grain-free line. This is in spite of the growing concerns linking grain-free diets to heart disease.

But what exactly is a grain-free diet? To be accurate, there is no universal definition of grain-free, although it can be generally thought to refer to those pet food formulas that have eliminated all grains, including wheat products, rice, corn and oats. They often include exotic ingredient alternatives, including peas, lentils or sweet potatoes.

Such diet trends appear to have piggybacked off the increased incidence in allergic diseases, being advertised as ideal for food allergic pets. In addition, was the growing theory that commercial pet food should closely match the diet profile of our pet’s genetic ancestors. It was commonly used in advertising these lines that Wolves do not eat grains.

What is Dilated Cardiomyopathy?

Dilated Cardiomyopathy is an acquired heart disease in which the pumping chambers of the heart expand in size. This results in muscle that is weak, and ultimately less effective at contracting. The heart can no longer efficiently pump blood through the body. For a period of time, the body can compensate. The kidneys jump into action, retaining the fluid to increase blood volume. While this works as a short term solution, the ultimate result is fluid accumulation in the heart and heart failure.

DCM may be acquired due to nutritional deficiencies. The classic example is taurine deficiency in cats. Taurine is an amino acid required for the development and function of the myocardium – the muscle of the heart. Cats cannot synthesize their own Taurine and, prior to the routine inclusion in commercial cat food, were at high risk of developing DCM. Most dogs can create their own Taurine, so are not generally susceptible to this type of heart disease. We think that predisposed dogs breeds may have an inability to make their own taurine.

In addition, L-carnitine is another amino acid that may play a role. In people, this amino acid allows muscle cells to produce the energy needed to contract. There is very limited information on its importance in DCM in dogs, but some small studies in Boxers and American Cocker Spaniels show some association between deficiencies in L-carnitine and dysfunction of heart contraction.

Is a Grain Free Diet Linked to Heart Disease in Dogs?

Over the past 8-10 years there have been increased reports of DCM in dogs. This increase has mirrored the rapid expansion of trendy, boutique pet food lines. Specifically, this increase has occurred in the group of dogs eating grain-free diets (as well as exotic-ingredient, vegetarian/vegan, or home-prepared diets).

While we have always seen DCM in certain breeds, the incidence in these at risk breeds appears to increase when eating a grain free diet. In addition, we are seeing grain-free related DCM develop in very young dogs and in breeds that are not typically at risk.

What Pet Foods Have Been Linked to Dilated Cardiomyopathy?

Over the last year, the FDA has been evaluating this link between grain free diet and DCM. They have been compiling data submitted by astute veterinarians and pet owners. On June 27th, the FDA released an update and provided the public with specific details about the nature of the cases submitted.


The above graph shows the types of diets that are implicated. As you can see, the diets implicated are predominantly grain-free and often include exotic substitutes, such as peas and lentils.


The above graph shows the dog food brands most frequently implicated in cases of DCM. As you can see, these are commonly fed brands: Acana, Signature, Taste of the Wild, 4Health, Earthborn, Blue Buffalo, Fromm, Merrick, Natural Balance, Orijen, etc. The list goes on.

What makes this information particularly disturbing is that grain-free is particularly trendy in the pet food industry. The named diets are generally expensive, boutique diets and considered by many to be best of the best. I have hope that the pet food industry will eventually respond to these studies and return to balanced grain-included diets, but I cannot be sure.

How Does Grain Free Food Cause Heart Disease?

The short of it is that we do not know. At the time of this article, the FDA has found a strong correlation between the aforementioned diets and the development of DCM, but has not yet uncovered the mechanism behind it. Taurine deficiency may play a role, perhaps in propensity to development of DCM, but is not thought to be the primary cause. I will provide updates to this article in the future, as we learn more.


My Dog Has Been Eating Grain Free. What Should I Do?

As I have mentioned earlier, the grain-free phenomenon has taken over the bulk of the high-end, boutique pet food market. This means that a lot if pets are currently eating grain free diets. As I result, I have spoken with many concerned owners. I am currently making the following recommendations. Please be advised that these recommendations may change as we uncover additional information.


  1. Before you get ahead of yourself, check your ingredient label. If you are feeding a diet marketed as grain-free or one that lists peas, lentils or sweet potatoes as the primary carbohydrate source, consider transitioning your pet to a grain included diet. Similarly, if you are currently feeding a vegetarian pet food, consider transitioning to a animal protein, grain included diet. Most nutritionists recommend using the WSAVA guidelines for selection of commercial diets.
  2. If you have been feeding a diet that fits into the above category, talk with your veterinarian about what comes next. Often times these changes resolve with appropriate dietary therapy. However, your veterinarian may suggest cardiac evaluation via x-rays or echocardiogram based on breed or history.
  3. Consider monitoring blood taurine levels. In high risk breeds, many veterinarians recommend monitoring blood taurine levels. While we do not know the exact link between grain-free diets and DCM, we do know that some breeds are at risk for DCM secondary to taurine deficiency. If your pet has low blood levels of taurine, further cardiac monitoring and taurine supplementation will likely be recommended. At risk breeds include: American Cocker Spaniel, Golden Retriever, Newfoundland, and Dalmatian.
  4. Finally, talk with your veterinarian about their nutrition recommendations and continue to monitor FDA progress reports for current thoughts and recommendations regarding this discovery.


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