For Julie Carter's three-and-a-half-year-old son, Oliver, it was a routine vet visit.Golden Retriever. At least, that's how it was until the vet listened to Oliver's heart and uttered the phrase that would change his life: "He has a...heart murmur.“
It was February 2018, and Carter also brought up an interesting article from the Morris Animal Foundation website, noting a worrying increase in the number of goldens diagnosedDilatative Kardiomyopathie (CMD). These dogs had two things in common: they were deficient in taurine, an amino acid, in their blood, and they were fed small-scale dog food, often with unusual ingredient lists, grain-free or high in legumes. Oliver was on this diet. He had low taurine levels. And he had DCM.
Oliver, who is now under the care of a veterinary cardiologist, was immediately switched to a conventional grain-based diet and received taurine supplements and heart medication. He remained symptom-free until one day, without warning, he suffered a fatal cardiac arrhythmia while walking across the kitchen floor. It was August 2018, six months after her diagnosis and just five days after she celebrated her 4th birthday.
DCM is a serious heart muscle disease that can be fatal. Occurs more frequently inlarge breeds, and in some breeds it is thought to have a genetic component. It is also common in middle-aged to older-aged dogs. Goldens are not generally considered a risk breed for DCM, but they are at risk of taurine deficiency.
taurine and heart disease
Taurine, an amino acid found in meat in abundance, has been linked to cases of DCM in cats for the past 30 years. It turned out that commercial cat food did not contain enough taurine. The addition of taurine to the diet virtually eliminated DCM in cats.
Taurine was immediately suspected in canine CMD, but relatively few cases of taurine-deficient CMD have been identified in dogs. However, certain diets, particularly those high in lamb, rice bran, or fiber (especially beet pulp) and very low-protein diets, have been linked to taurine deficiency in dogs.
Fast forward to 2018. Veterinary cardiologists have started noticing a higher than average number of dogs with TMD. At Tufts University, Lisa Freeman, DVM, Ph.D., DACVIM, a board-certified veterinary nutritionist specializing in research into the nutritional effects of heart disease, reported that an alarming number of these dogs were eating what she called BEG (boutique, exotic) - diets without ingredients or without grains).
Boutique diets are made by small businesses with no nutrition testing facilities. Diets with exotic ingredients use unusual sources like kangaroo or duck that have not been extensively tested, but use more common sources like chicken or beef. Grain-free diets replace grains like rice and corn with potatoes orLegumes (beans, peas and lentils)as a carbohydrate source. No study has ever shown that a grain-free diet is superior to a grain-containing diet.
The FDA gets involved
Freeman worked with several veterinary cardiologists and alerted the Food and Drug Administration (FDA). In July 2018, the FDA announced it had found enough evidence to investigate. In November 2018, Freeman and his collaborators published an op-ed in the Journal of the American Veterinary Medical Association. It would be one of the most downloaded articles in the history of this publication.
The FDA hassince the release of several updates. From January 2018 to April 2019, the FDA received reports of 553 dogs with DCM compared to previous years, with the number ranging from zero to three dogs. These included 95 Golden Retrievers, 62 crossbreeds, 47 Labrador Retrievers, 25 Great Danes and over 50 other breeds with more than one report.
The FDA report lists 16 dog food companies that have had 10 or more DCM cases related to their food, but many more foods are affected. The report is probably not about the brands themselves, but about the similarities between these foods.
When examining the diets, no protein source was found to be over-represented. In fact, the most common proteins were chicken, lamb, and fish, although some included uncommon proteins like kangaroo, bison, or duck. More than 90% of the diets were grain-free and 93% of themDiets included peas or lentils. A significantly smaller proportion were potatoes. When these foods were tested, they contained the same average levels of protein, fat, taurine, and taurine precursors as the grain-based products.
Joshua Stern, DVM, Ph.D., DACVIM, was one of the first veterinary cardiologists to notice the increase in DCM cases in golden retrievers. Since then, Stern of the College of Veterinary Medicine at the University of California, Davis, has been studying Goldens with DCM and taurine deficiency. In an unpublished study of 24 Golden dogs with confirmed DCM and low taurine, all but one dog showed significant heart improvement after changing their diet and adding extra taurine. At the time of DCM diagnosis, all dogs were eating BEG diets.
Although many dogs consuming BEG diets do not appear to develop DCM, veterinary cardiologists recommend diets from established manufacturers. They conduct feeding tests and use standard ingredients like chicken, beef, rice, corn, and wheat. They point to five American manufacturers: Purina, Hills, Royal Canin, Iams and Eukanuba.
Critics claim that the number of dogs reported compared to the number consuming these diets hardly represents an epidemic and that there are no controlled feeding trials comparing DCM rates on BEG and non-BEG diets. However, most DCM cases are still unreported and small BEG companies do not conduct feeding trials.
At least one study is still ongoing. Researchers at the University of Florida's College of Veterinary Medicine have begun a study funded by the AKC Canine Health Foundation to determine if diet type affects echocardiographic, taurine, or blood biomarker levels in apparently healthy dogs. In dogs with abnormalities, the diet is changed and examined again a year later. Two "endangered" breeds (Goldens andDobermann-Pinscher) and two “no risk” breeds (WhippetseMiniature Schnauzer) will participate.
"We are working hard to answer this question as quickly as possible," said lead researcher Darcy Adin, DVM, DACVIM. This study won't answer all the questions, but hopefully it will address the question of whether diet-related DCM is real, if so, what types of foods are associated with it, whether taurine deficiency plays a role, and whether cardiac biomarkers in the blood might be useful for the detection and whether an improvement can be observed after a nutritional intervention.
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Meanwhile, dog owners remain concerned. Excellent resources are available thanks to dedicated vets and dedicated dog owners. Several Facebook pages are dedicated to the topic; The most popular, Taurine Deficiency Dilated Cardiomyopathy (Nutrition), has over 100,000 members. Other groups include Taurine Deficiency in Golden Retrievers and the Canine Nutritional DCM Support Group, a support group for owners who have an affected dog or have lost their dog to DCM. There's one toowebsite.
More than a year after Oliver's death, Carter is coming to terms with his loss by helping others deal with their deaths and raising awareness of the issue. This has prompted many owners to have their dog's heart checked by a veterinary cardiologist.
But Oliver isn't her only concern. Riley, Carter's 9-year-old Golden, was diagnosed with the same condition. "While their cases share many similarities, the most striking is the fact that Oliver and Riley ate the exact same food for several years. … a grain-free, low-ingredient diet full of vegetables,” says Carter. Carter also has "an adorable 1-year-old Golden named Finn who has never been on a BEG diet and never will be."
Oliver is arguably the best-known victim of DCM. "The decision to be proactive and educate others about this potentially fatal disease was a quick and easy decision," Carter recalls. “When Oliver was diagnosed in February 2018, there was very little publicly available information about canine nutritional DCM. Shortly after Oliver's diagnosis, I dubbed it the "face of dilated cardiomyopathy" in the hope that putting a face to this horrific disease would draw dog owners' attention and make it easier to educate them.
"Oliver is often recognized as the face of DCM, but he's not the only one," says Carter. “There are hundreds of other dogs that are suffering and dying from this preventable disease. ... I've seen firsthand how many of these heartbroken families crumble under the emotional, physical and financial toll that this diagnosis brings."