It was a routine vet visit for Oliver, Julie Carter’s 3½-year-old Golden Retriever. At least, it was until the vet listened to Oliver’s heart and uttered the sentence that would change her life: “He has a heart murmur.”
It was February 2018, and Carter had also brought in an interesting article from the Morris Animal Foundation website noting a disturbing upswing in the number of Goldens diagnosed with dilated cardiomyopathy (DCM). These dogs had in common two things: They had a deficiency of taurine, an amino acid, in their blood, and they were fed boutique dog foods from small companies often with unusual, grain-free, or legume-rich ingredient lists. Oliver was eating such a diet. He had a low taurine level. And he had DCM.
Oliver, now under the care of a veterinary cardiologist, was immediately placed on a mainstream diet containing grain and was given taurine supplements as well as heart medications. He remained symptom-free until one day, without warning, he suffered a fatal arrhythmia while walking across the kitchen floor. It was August 2018, six months after his diagnosis, and just five days after celebrating his 4th birthday.
DCM is a serious disease of the heart muscle that can ultimately lead to death. It occurs more often in large breeds, and in some breeds, it’s thought to have a genetic component. It also typically occurs in middle-aged to older dogs. Goldens are not considered an at-risk breed for DCM in general, but they are at risk for taurine deficiency.
Taurine and Heart Disease
Taurine, an amino acid that’s abundant in meat, was implicated in cases of cat DCM 30 years ago. It turned out commercial cat foods didn’t contain sufficient taurine. When taurine was added to the food, DCM in cats basically disappeared.
Taurine immediately became suspect in dog DCM, but relatively few instances of taurine-deficient DCM have been identified in dogs. Certain diets, however, notably those high in lamb, rice bran, or fiber (especially beet pulp) and very low–protein diets have been associated with canine taurine deficiency.
Fast-forward to 2018. Veterinary cardiologists started noticing higher than usual numbers of dogs with DCM. At Tufts University, Lisa Freeman, DVM, Ph.D., DACVIM, a board-certified veterinary nutritionist with a research emphasis on nutritional effects of heart disease, reported an alarming number of these dogs were eating what she called BEG (boutique, exotic-ingredient, or grain-free) diets.
Boutique diets are produced by small companies without nutritional testing facilities. Exotic-ingredient diets use unusual sources, such as kangaroo or duck, which have not received extensive testing more common sources such as chicken or beef have. Grain-free diets replace grains such as rice and corn with potatoes or legumes (beans, peas, and lentils) as a carbohydrate source. No study has ever shown grain-free to be superior to grain-inclusive diets.
The FDA Gets Involved
Freeman collaborated with several veterinary cardiologists and alerted the Food and Drug Administration (FDA). In July 2018, the FDA announced it had found sufficient evidence to investigate. In November 2018, Freeman and her collaborators issued a commentary published in the Journal of the American Veterinary Medical Association. It would become one of the most downloaded articles in the history of that publication.
The FDA has since issued several updates. From January 2018 through April 2019, the FDA received reports of 553 dogs with DCM compared with previous years that ranged from zero to three dogs. These included 95 Goldens, 62 mixed-breeds, 47 Labrador Retrievers, 25 Great Danes, and more than 50 additional breeds with more than one report.
The FDA report lists 16 dog-food companies that had 10 or more cases of DCM associated with their food, but many more foods are involved. The brands themselves are probably not the important part of the report, but rather what these foods have in common.
When the diets were examined, no protein source stood out as being over-represented. In fact, the most common proteins were chicken, lamb, and fish, although some contained unusual proteins such as kangaroo, bison, or duck. More than 90 percent of the diets were grain-free, and 93 percent of the diets contained peas or lentils. A far smaller proportion included potatoes. When these foods were tested, they contained the same average percentage of protein, fat, taurine, and taurine precursors as grain-containing products.
Joshua Stern, DVM, Ph.D., DACVIM, was one of the original veterinary cardiologists who noticed the increase in DCM cases in Golden Retrievers. Since then, Stern, of the University of California, Davis, School of Veterinary Medicine, has been studying Goldens with DCM and taurine deficiency. In an unpublished study of 24 Goldens with confirmed DCM and low taurine, all but one dog had substantial cardiac improvement after a diet change and the addition of supplemental taurine. All of the dogs had been eating BEG diets at the time DCM was diagnosed.
While many dogs eating BEG diets do not appear to be developing DCM, veterinary cardiologists are recommending feeding foods made by well-established manufacturers. These conduct feeding trials and use standard ingredients such as chicken, beef, rice, corn, and wheat. They point to five American manufacturers: Purina, Hills, Royal Canin, Iams, and Eukanuba.
Critics contend that the number of reported dogs compared to the number eating these diets hardly constitutes an epidemic and that no controlled feeding trials exist that compare DCM rates in BEG versus non-BEG diets. However, most cases of DCM still go unreported, and the smaller BEG companies don’t conduct feeding trials.
At least one study is now underway. Researchers at the University of Florida College of Veterinary Medicine have begun an AKC Canine Health Foundation-funded study to determine if diet type has an effect on the echocardiographic, taurine values, or blood biomarker values of outwardly healthy dogs. Dogs with abnormalities will be offered a diet change and then re-checked for a year afterward. Two “at-risk” breeds (Goldens and Doberman Pinschers) and two “not-at-risk” breeds (Whippets and Miniature Schnauzers) will participate.
“We are working hard to help answer this question as soon as possible,” says lead researcher Darcy Adin, DVM, DACVIM. This study will not answer every question but hopefully will address the issue of whether nutritionally associated DCM is real, if so what types of foods are associated with it, whether taurine deficiency plays a role, whether blood cardiac biomarkers may be useful for detection, and whether improvement can be seen after nutritional intervention.
Meanwhile, dog owners remain concerned. Thanks to dedicated veterinarians and devoted dog owners, there are excellent resources are available. Several Facebook pages are devoted to the topic; the most popular, Taurine Deficient (Nutritional) Dilated Cardiomyopathy, has more than 100,000 members. Other groups include Taurine Deficiency in Golden Retrievers and the Canine Nutritional DCM Support Group, a support group dedicated to owners who have an affected dog or have lost their dog to DCM. There is also a website.
More than a year after Oliver’s death, Carter copes with her loss by helping others cope with theirs, and by spreading awareness of the problem. This has prompted many owners to have their dogs’ hearts checked by a veterinary cardiologist.
But Oliver isn’t her only concern. Riley, Carter’s 9-year-old Golden, has been diagnosed with the same disease. “While their cases share several similarities, the most glaring one is the fact that both Oliver and Riley ate the exact same food for several years. … a grain-free, limited-ingredient diet loaded with legumes,” Carter says. Carter also has “a loveable 1-year-old Golden named Finn who has never eaten a BEG diet, nor will he ever be fed one.”
Oliver is undoubtedly the best-known DCM victim. “Deciding to be proactive and educate others about this life-threatening disease was a quick and easy decision to make,” Carter recalls. “When Oliver was diagnosed in February 2018, there was very little information accessible to the public about canine nutritional DCM. Shortly after Oliver’s diagnosis, I dubbed him the ‘Face of Dilated Cardiomyopathy,’ hoping that putting a face to this horrible disease would get the attention of dog owners and make it easier to educate them.
“While Oliver is often recognized as the Face of DCM, he is not alone,” says Carter. “There are hundreds of other dogs suffering and dying from this preventable disease. … I have seen firsthand how many of these heartbroken families are crumbling under the emotional, physical, and financial weight that comes along with this diagnosis.”