Archer’s Broken Heart – Are Diets Causing Heart Disease In Dogs?

Archer patiently having a blood sample taken

Cat Reynolds, who helped me open Parmer Lane Pet Hospital in 2006 and has worked with me as a veterinary technician for over 30 years, knew something was wrong.

While vacationing in Colorado last month, she noticed Archer, her 4 year old Golden Retriever, seemed to tire more easily than usual and was just not himself. He was eating fine and she was not seeing anything obvious, but after getting home things were still not right. Even though he was still a young dog, she decided to bring him in for a workup. It turned out to be a good decision.

A physical exam failed to find anything definitive although he had lost a couple of pounds, again suggesting there was something amiss. When blood work and parasite testing were inconclusive, special tests for hormone levels and specific blood diseases were sent off. The tests all failed to show a problem. It was about then that Cat began noticing a mild, persistent cough. Chest x-rays were immediately ordered and there was the answer – an enlarged heart indicating heart disease. Ultrasound by a cardiologist confirmed the diagnosis – Dilated Cardiomyopathy (DCM).

X-ray of Archer’s greatly enlarged heart

DCM is a disease that causes the heart to enlarge and weaken, eventually resulting in heart failure and death. In dogs, it has always been a disease associated with certain large breeds such as Dobermans, Boxers, and Great Danes. Recently however, it has become increasingly common in breeds we are not used to seeing it in, most notably in Golden Retrievers like Archer. As veterinary cardiologists around the country began seeing these unusual cases with increasing frequency, they began to suspect a link with the “grain free” and “limited ingredient” diets that are overwhelmingly popular now.

Early in my career, DCM was a fairly common heart disease in cats. There was no cure and the goal of treatment was merely to help the patient feel better for as long as possible.  Then in 1987, a paper was published linking DCM in cats to a deficiency in taurine, an amino acid found naturally in meat. Taurine was found to be deficient in commercial cat foods and once corrected, DCM virtually disappeared in cats. It was one of the more satisfying advances in veterinary medicine in my lifetime.

It was only recently that I began hearing reports of a rise in unusual DCM cases in dogs that could possibly be related to diet. It did not get my full attention because there was no clear consensus on how food might be a problem. It was well known that dogs, unlike cats, did not need taurine in their diet. Taurine was still suspected as being involved somehow, but when affected dogs were tested, some had low levels, others were normal. All seemed to agree that diets labeled grain free or limited ingredients were somehow a cause, but there was no single brand or ingredient that could be blamed. Diets that were linked to DCM in some dogs, seemed to cause no problems in most others. Finally, this past July the FDA responded to the increased reports by putting out an alert to pet owners and veterinarians about a possible connection between diet and dilated cardiomyopathy in dogs. In particular, it singled out those diets containing high amounts of “potatoes or multiple legumes such as peas (and) lentils”. Currently, the FDA’s Center for Veterinary Medicine and the Veterinary Laboratory Investigation and Response Network, a collaboration of government and veterinary diagnostic laboratories, are investigating.

Archer vacationing in Colorado

With little hard evidence of what the problem was, I have been reluctant to discuss diets and the risk of heart disease with clients until we knew more. Archer has changed my mind. I remember talking to Cat early on about what she was feeding and nodding approvingly when she told me one of the widely popular grain free diets. While I was unconvinced a grain free or limited ingredient diet was necessarily healthier than a more traditional food, I saw no harm in it. I also did not think there was any reason some of the unconventional proteins used in these foods like bison, venison, and kangaroo could be a problem. Now, along with many others studying these cases, I am not so sure. It does seem that there is something very wrong with these formulations, at least for some dogs.

What are the diets that concern me? Until we know more, my recommendation is to avoid exclusively feeding any dry kibble diet that is labeled as limited ingredient or grain free. Any diet that has protein sourced primarily from unconventional meats like venison, kangaroo, or bison is to me suspect. Those with potatoes or legumes among the first ingredients (meaning one of the main ingredients) should especially be avoided. Even though it is not known how these formulations are linked to cases of DCM, there is enough suspicion that I will play it safe for now. Ideally, I recommend feeding one of the many foods and formulations we have long experience with that include traditional grains and more conventional protein sources. Owners of dogs being fed a grain free, limited ingredient diet for a medical reason such as food allergies should discuss with their veterinarian if what they are feeding is still the best choice for their pet.

Archer has been put on the amino acid supplements taurine and L-carnitine and has changed over to a diet with more conventional ingredients. He is also taking pimobendan, a medication to help with his poor heart function. Not only will Cat be watching him closely at home, both the doctors at Parmer Lane and the cardiologist will be doing follow up tests and exams to monitor his progress. Hopefully, Archer will be one of those patients whose heart damage can be reversed once given the proper mix of nutrients.

Archer dressed up for one of his frequent visits to Parmer Lane

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