Several years ago, Josh Stern, a veterinary cardiologist at the University of California Davis noticed an alarming trend.
Stern began diagnosing more and more golden retrievers with a heart disease called dilated cardiomyopathy (DCM), an unusual disease in the breed. In this condition, the heart muscles dilate. The heart enlarges and can no longer pump properly, leading to congestive heart failure and death.
Another trend he noticed is that many of these dogs were being fed the same grain-free diet and had low blood levels of an important amino acid called taurine.
Grain-free diets frequently use potatoes or legumes (peas and lentils for example) as their carbohydrate source instead of grains. Examples of a grain are wheat, rice, oats, cornmeal and barley.
It has been popular to feed a grain-free diet to dogs because consumers view grains as being “less healthy” than non-grain carbohydrates. Some people have a sensitivity to grains and therefore also want a grain-free diet for their dogs. It is important to know, however, that grain sensitivity is very uncommon in dogs.
Taurine is necessary amino acid for heart muscles to function properly. Cats cannot manufacture their own taurine, and it is essential that it be supplemented in their diet. Dogs are capable of making some taurine but not to the level that is needed for good heart health.
Although a definitive answer has not been arrived at yet, it is thought that the diet being fed to the patients that developed DCM was low in taurine, which led to the development of their heart condition.
DCM can be a genetic disease, but it is also known that it can be an acquired disease if a patient is fed a low-taurine diet. The vast majority of Stern’s patients improved when their diet was changed and they were supplemented with taurine.
Cardiologists are still investigating these cases. If you are currently feeding a non-prescription grain-free diet with peas, lentils, other legume seeds or potatoes as main ingredients, veterinarians are recommending that you slowly transition your dog to a diet that is not marketed as grain-free.
If your dog is acting ill — especially if your dog is lethargic, coughing or has a poor appetite — it should be evaluated by a veterinarian. DCM can be diagnosed with an x-ray in most cases. An echocardiogram (ultrasound of the heart) likely will be recommended if the concern for heart disease is present.
Blood taurine levels can be evaluated. But it should be noted that these levels are only meaningful if a blood level is measured before and after a diet change.
Because of individual patient variation in blood taurine levels, a single reading does not provide enough information for veterinarians to interpret the results, and there were some atypical breeds that seemed to develop diet-associated DCM but had normal blood taurine levels. It should also be noted that this test is an expensive test to run, typically ranging $400–$500.
If you have further questions about grain-free diets and heart disease, your veterinarian is the best source of information.
CLARIFICATION: A previous version of this column specifically named two grain-free diets. Westgate Pet Clinic recommends avoiding all grain-free diets for pets, not just those from a particular company.