Grain-free Diets Are Potentially Linked to Heart Disease in Dogs

By Abigail Messina, DVM: Veterinarian at Vet At Your Door, P.C. and
Deirdre Frey, VMD: Owner, Veterinarian at Vet At Your Door P.C.

The problem: As you may or may not have heard, this past July the FDA administered a warning that some diets may be associated with Dilated Cardiac Myopathy (DCM) in dogs.  Specifically, the diets in cases reported to the FDA frequently list potatoes or multiple legumes such as peas, lentils, other “pulses” (seeds of legumes), and their protein, starch and fiber derivatives early in the ingredient list, indicating that they are main ingredients. 

DCM is a heart condition where the heart muscle gets thin and flabby, and the chambers of the heart become dilated, causing the heart to be weak and unable to beat properly.  As of now, it is thought that many of the ingredients in several “fad” diets block the adequate absorption of taurine - an amino acid that is integral to heart health.  Taurine deficiency is proven to be related to DCM.

More specifically, the incidence of DCM has increased in dogs eating boutique, grain-free, or diets with exotic ingredients such as kangaroo, lentils, duck, pea, fava bean, buffalo, tapioca, salmon, lamb, barley, bison, venison, chickpeas, potato, or other legumes/beans/seeds. It has also been seen in pets being fed vegan, raw, or home-prepared diets.  It is unclear at this point whether there are certain breeds that are more likely to develop DCM, however there seems to be higher incidence in Golden Retrievers and Cocker Spaniels.

Why is there such a higher incidence now than before?  Many more pet owners are feeding grain-free, boutique or exotic ingredient diets because they are portrayed, via excellent marketing, as more natural, or healthier than traditional diets.  These companies’ marketing messages also often imply that grains cause many health issues with pets.  In fact, the actual incidence of grain allergy in dogs is less than 0.5%.  Moreover, there is no scientific evidence that feeding these types of diets is healthier than any other diet.  Additionally, many of these food companies do not have veterinary nutritionists on staff, nor do they perform long-range peer-reviewed studies on their food. As demonstrated by this DCM issue, this can be very dangerous.

Here are some FAQs:

1. How do I know if my dog’s food falls into this category?
Overall, grain-free, exotic, or boutique brands seem to be the biggest culprits.  Look at the ingredients of your dog food.  Are potatoes or multiple legumes such as peas, lentils, other “pulses” (seeds of legumes), and their protein, starch and fiber derivatives in the first four or five ingredients? Are there exotic proteins in the first few ingredients (buffalo, bison, alligator, etc.)? If either of these questions are yes, your dog may be affected.  If you’re still not sure, you can email us at and we can tell you if your food may be one of those affected.

2. OK so what do I do if my dog may be affected?
The safest thing would be to test a taurine level (about $170) and have us assess your dog’s cardiovascular status.  If the taurine level is below normal or we notice any cardiac abnormalities on our exam, a supplement should be started immediately, the food switched, and ideally an echocardiogram (ultrasound of the heart) should be performed. 

3.  What are signs of DCM?
Decreased energy, cough, difficulty breathing and episodes of collapse.  Unfortunately, there may be no symptoms until the DCM is end-stage.

4.  What if I can’t afford the blood work or diagnostics?
We know this can add up. If you can’t afford testing, we recommend switching your dog as soon as possible to a safe, nutritious food with a proven track record (see below for ideas).  Supplementing taurine without diagnostics can be dangerous so it isn’t recommended.  It’s possible that switching the food can be enough to reverse the course of asymptomatic DCM. 

5. Are cats affected too?
There hasn’t been as much research done on cats and at this time, there doesn’t appear to be a correlation between these types of diets and DCM in cats. 

6.  What if I am feeding my dog one of these foods and I can’t afford blood work or diagnostics?
We recommend switching them as soon as possible to a safe, nutritious food (see below for ideas).  Supplementing taurine without diagnostics can be dangerous so it isn’t recommended. It’s important to note that there is a risk that there is DCM happening in your dog that you won’t know about, but it’s possible that switching the food can be enough to reverse the course of the DCM. 

 7. My dog’s skin and/or GI system are now so much better after switching to one of these diets.  What should I do?
There are true food allergies that can be helped by these foods due to their limited ingredient and/or exotic protein nature.  However, now that DCM is a risk, you can either find another brand (see below) and slowly switch to that food to see if skin / GI issues recur.  Alternatively, you can test your dog’s taurine level. If it’s normal and you’ve been feeding that food for awhile, it is likely ok to continue feeding. 

8.  What are brands you recommend switching to?
There are about forty bajillion brands out there so this is a difficult question.  REST ASSURED, we are not paid by any company to endorse them and we are not “brainwashed” by them either.  We recommend foods made by companies that do top-notch food trial studies on animals for LONG periods of time (i.e. years) and who have veterinary board-certified nutritionists on staff.  Namely, Purina Brands - ProPlan, Merrick, Chow, ONE, etc.; Hill's brands: Science Diet, Healthy Advantage, etc.; or Mars brands: Royal Canin, Iams, Eukanuba, Nutro, Pedigree, etc.

9.  Where can I read more on this topic?
We recommend looking at Tufts School of Veterinary Medicine’s article and UC Davis School of Veterinary Medicine’s article on this important topic.  These are board-certified, unbiased, veterinary nutrition specialists talking about this problem. 

We know this is a scary topic, and that many of our clients feed grain free foods.  We promise to stay abreast of this topic as the research becomes more available and more scientific facts are brought to light, and we will continue to keep all of you in the loop as well.  As always, please don’t hesitate to reach out and ask any questions you may have about all this.