In recent years, there has been a spike in a type of heart disease called canine dilated cardiomyopathy (DCM). There is mounting evidence that this spike may be the result of diet-related trends in dogs.
Since DCM is a potentially fatal disease, the goals of this article are to (1) help you understand what DCM is, (2) risk factors for DCM, (3) and how to potentially avoid nutritionally-mediated DCM.
What is Canine Dilated Cardiomyopathy (DCM)?
DCM is a disease of the heart muscle, often with genetic or nutritional causes. It causes the chambers of the heart to become dilated and thinned. The heart's ability to pump blood effiently throughout the body is reduced, leading to signs associated with decreased oxygenated blood flow (lethargy, collapse, weakness, weight loss) or congestion of blood in the lungs (coughing, increased effort breathing, panting at rest). Heart arrhythmias (abnormal heart rhythms) may also result and could be life-threatening.
DCM is diagnosed using an echocardiogram (heart ultrasound), which is typically performed by a veterinary cardiologist. Treatment is typically in the form of oral medications (or oxygen and injectable medications in more urgent/life threatening situations).
In cases of nutritionally-mediated DCM, the disease has the potential to be reversed with diet change. The prognosis is less favorable for breeds that develop the disease due to a genetic predisposition.
DCM is most common in Golden Retrievers, Cocker Spaniels, Boxer dogs, German Shepherds, Great Danes, and Doberman Pinschers.
Has diet ever been associated with DCM before?
DCM used to be one of the most common cardiac diseases in cats. In 1987, a study was published revealing that DCM was associated with taurine (an amino acid) deficiency in cats and could be reversed with taurine supplementation. There is now additional taurine in common cat foods and DCM is an uncommon disease in cats (with the exception of cats eating home-cooked diets or formulations with poor quality control).
In 1995, veterinary cardiologists found evidence that certain breeds (Golden Retrievers, American Cocker Spaniels) may be predisposed to taurine deficiency. A later study in Cocker Spaniels showed that supplementation with taurine and L-carnitine could partially or completely reverse the disease. Since then, additional breeds have been associated to be at risk.
Which diets have been associated with nutritionally-mediated DCM?
BEG (boutique, exotic and grain-free) diets seem to be most commonly associated with nutritionally-mediated DCM. A grain-free diet is one that contains a high proportion of peas, lentils, other legumes, and/or potatoes as the main ingredient (in the top 10 ingredients).
These diets do not usually follow WSAVA (World Small Animal Veterinary Association) nutritional recommendations nor do they typically have AAFCO certification, to let us know that they are complete and balanced diets (appropriate to feed a dog long-term).
The most commonly implicated diets to cause DCM are listed in the FDA's investigation, here (and below).
In Dr. Joshua Stern's (UC Davis Cardiologist) recent study on 24 Golden Retrievers with nutritionally-mediated DCM, he found that all were taurine deficient and all 24 were on a BEG diet.
Which diets are "safe" for my dog?
Cardiologists currently recommend feeding dogs diets that follow WSAVA guidelines. If the diet has AAFCO certification (it should say this on the label), it should be a complete and balanced diet that is "safe".
Consider scheduling an appointment to discuss this topic with your veterinarian or even a veterinary nutritionist. This is a complicated topic!
Even though it's very scary to learn that feeding common diets can have such severe consequences, the good news is that this information is becoming more widely available and there are many very good diets available to choose from that will not negatively affect your dog's heart!
Dr. Lori Cesario
Board Certified Veterinary Oncologist
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