Shedding light on the heart disease grain-free pet food conundrum

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Much has been discussed in recent months about the potential association between grain-free pet foods and dilated cardiomyopathy (DCM) in dogs. To address this ongoing concern, the Washington State University College (WSU) of Veterinary Medicine has released a statement outlining the issue and providing feeding recommendations for dog owners.

Why the hype?

Last July, the FDA released an alert for veterinary professionals and pet owners regarding reports of DCM in dogs that had eaten pet foods containing peas, lentils, other legume seeds or potatoes as main ingredients. The reports were concerning because DCM was being noted in dogs not typically prone to the disease.

FDA issues update on possible tie between grain-free diets and heart disease

Its investigation is ongoing and the agency hasn't changed its recommendation to pet owners whose pets are not ill. Read the February 20, 2019 update here.

“While there has historically been some evidence of diet-responsive DCM in some breeds (golden retrievers, cocker spaniels, Newfoundlands, Irish wolfhounds, and Saint Bernards), the incidence of DCM in these breeds has appeared to increase when they were fed grain-free, vegetarian/vegan, or exotic ingredient pet foods,” explains WSU professor O. Lynne Nelson, DVM, MS, DACVIM (cardiology), who coauthored the statement, in the WSU Insider. “Curiously, other cases occur in breeds without a history of DCM or in very young dogs.”

According to the WSU website, DCM is a cardiac disease in which the heart muscles become weak, reducing the heart's ability to pump blood effectively. Disease progression leads to enlargement of the heart chambers, possible valve leakage and fluid accumulation in the lungs resulting in congestive heart failure. Dogs with mild disease may not show clinical signs, whereas in other cases the condition can be life-threatening.

One potential culprit in these cases is the lack of the amino acid taurine in grain-free pet foods. However, the WSU statement notes that while taurine deficiency may play a role in the identified DCM cases, “it is unclear whether taurine deficiency is a cause or merely an association with yet unknown other dietary components.” Some breeds may be more sensitive to changes in nutritional components in their food, which may suggest breed-related differences in metabolism. Alternatively, the balance of amino acids in some dog food formulations may be inappropriate, or the amino acids may not be well absorbed by the pet.

What's a pet owner to do?

In addition to advising pet owners to always choose a diet made by a well-established manufacturer, the statement provided several recommendations:

• Healthy dogs should feed a diet that contains standard ingredients (chicken, beef, rice, corn and wheat).
• Dogs that have a medical condition that requires a nonstandard diet should be fed a diet that has undergone extensive feeding trials through the Association of American Feed Control Officials (AAFCO).
• DCM related to diet may be reversible if it is detected early. Dogs diagnosed with DCM that are eating a diet with nonstandard ingredients should be switched to a diet that contains standard ingredients as noted above.
• Whole blood and plasma taurine concentrations should be measured in dogs with DCM being fed a grain-free diet, and a dietary taurine supplement should be added if concentrations are found to be low or low-normal, the WSU statement continues. Follow-up echocardiography can help assess for improvement in heart function. In addition, screening echocardiography should be obtained for all household dogs being fed the nonstandard diet.
• Finally, for dogs with suspected diet-related DCM, the WSU statement advises pet owners to save food samples and product labels for everything they are feeding, including treats and supplements.

All cases should be reported to the FDA.