Jul 17 2018

Are Grain-Free Diets Causing Heart Disease in Dogs?

Mariposa is a 4 year old, fun loving and outgoing lab mix. During her routine examination the veterinarian noticed that she had a painful slab fracture of her large maxillary carnassial tooth. It was recommended to do a thorough oral exam with dental x-rays under general anesthesia, along with a dental cleaning. Mariposa received a full physical exam including evaluation of her heart for any murmurs or arrhythmias, and received a clean bill of health from the veterinarian. She had full pre-anesthetic blood work performed and this was all completely normal.

Mariposa was scheduled for her dental procedure a couple of weeks later. The morning of her dental procedure, she received another full physical exam that included auscultating her heart and lungs, and this was completely normal.

Mariposa was anesthetized and monitored closely by the veterinary assistant and veterinarian during her procedure. Every anesthetized patient is monitored with blood pressure, ECG, pulse ox and capnography. Their heart is listened to, mucous member color evaluated and capillary refill time is monitored as well. This ensures that if there is any problem then it is picked up at the earliest possible moment and the appropriate intervention is applied.

Mariposa did great for most of her dental procedure. Unfortunately, the tooth that was fractured needed to be extracted. Dog’s carnassial teeth are large and have 3 roots. In a large breed dog with a healthy tooth this can take up to an hour. Luckily Mariposa’s extraction went well without any complications and the gingiva was sutured closed.

At the very end of the procedure Mariposa’s heart rate and blood pressure dropped and her mucous membrane color was pale. Immediately, the anesthetic was ended and lifesaving medications were given through her IV catheter. Thankfully, Mariposa responded and her heart rate and blood pressure stabilized. She recovered from her anesthesia without any further incidence.

The question is why did a healthy, young dog have trouble with anesthesia so suddenly? The first thing that the veterinarians thought of was underlying heart condition. A cardiologist was phoned and consulted. One of the first questions the cardiologist asked was what kind of food was Mariposa eating? Mariposa had been eating a grain free adult diet. The cardiologist advised an immediate echocardiogram. Recently many dogs that are eating grain free diets have been getting a cardiac condition called Dilated Cardiomyopathy (DCM). It is suspected that some grain free diets are deficient in nutrient called Taurine.

It is well known that Taurine is needed for the heart muscle to work properly. If a dog or cat has low taurine levels they will develop DCM. Recently there has been a jump in cases of DCM in dogs on grain free foods.

Mariposa received an echocardiogram that confirmed she had DCM. She was placed on taurine supplementation, cardiac medications and her diet was changed.

Mariposa is doing great and will receive a follow-up echocardiogram in 6 months. Many times dogs with DCM due to taurine deficiency will improve once they receive adequate levels of taurine in their diet.

There are studies currently being conducted to try and identify all the factors in these cases. For now, if you are feeding your dog a grain free diet it is important to ensure that is complete and manufactured by a reputable company.

Below is a link that describes question you can ask your pet food company to ensure your pet is on a complete diet. This goes for all pet foods, not just grain free.


Grain free diets are often marketed as healthier for your pet. There is NO evidence that this is the case. Grain free does NOT help with allergies, another common myth.

Recently the FDA has come out with a statement about a link with grain free diets and DCM.


Currently, there is active research being done to ensure that we are completely understanding the link between grain free diets and cardiac disease. As the new data emerges, Hawthorne Hills Veterinary Hospital will keep you updated with the latest information.

Below are some resources that discuss the link between grain free diets and DCM.

***UPDATE FROM TUFTS: 11/29/2018

It appears that dogs are at risk if they are: 1) on a boutique foods (with fruits and vegetables not typically fed in the past)  2) on exotic ingredients  3) on grain-free foods. Tufts now refers to this a BEG diets. It does not appear to be a Taurine deficiency as more than 90% of dogs have normal taurine levels. Here is a link to their newest information:  http://vetnutrition.tufts.edu/2018/11/dcm-update/ 





Adrian Nevill, BVM&S Hawthorne Hills Veterinary Hospital, Seattle WA | Cardiac, Care & Wellness, Dental Care, Diseases, Heart Disease, Heart Murmurs, Medical Conditions, Medical Issues, Nutrition, Routine exams, Taurine, Tooth Fracture

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