DCM Link to Pet Food Unfounded

From the first day that FDA and veterinary cardiologists and nutritionists labeled grain-free BEG diets as causing DCM in dogs, I called Bulls**t. This was just a ploy by the large pet food manufacturers using their influence on FDA to single out smaller companies that are gaining an increase in market share. Unfortunately, their ploy worked, resulting in discontinuation of many wonderful pet foods and huge revenue losses for good companies. The veterinary community has bought into this rhetoric, often recommending a return to poor quality, grain-filled, low-meat diets for dogs.

Up to 75% of all cardiovascular disease in dogs is chronic degenerative valve disease. The second most common heart disease is reported to be DCM or Dilated Cardiomyopathy. This is a condition in which the heart muscle becomes thin and ineffective at pumping blood, resulting in a very enlarged or dilated heart. Historically, DCM has been considered to be primarily an inherited disease, found commonly in breeds such as Great Danes, Dobermans, Boxers, Irish Wolfhounds, Cocker Spaniels, and Newfoundlands (and now Golden Retrievers).

Symptoms include panting, lethargy, coughing, lack of appetite, bloated abdomen, and collapse. Diagnosis is made using electrocardiograms, radiographs, and echocardiography. 

In the past few years, concerns have been raised by veterinary cardiologists and nutritionists that more cases of DCM have been diagnosed. Questions were raised regarding the relationship of diets such as grain-free diets, legume-filled diets, novel protein diets, and diets produced by small manufacturers with the uptick in cases of DCM. Although there was no PROOF that these diets cause cardiomyopathy, some individuals (mostly funded by large pet food companies) were very outspoken about the need to move away from these diets and return to feeding grain-filled kibble manufactured by major pet food corporations.

"Dr. Freeman has received research support from, given sponsored lectures for, or provided professional services to Aratana Therapeutics, Hill’s Pet Nutrition Nestlé Purina PetCare, and Royal Canin. Dr. Heinze has done consulting for Lafeber and WellPet, given sponsored talks for Nestlé Purina PetCare and the Pet Food Institute; and provided professional services to Balance IT.com and Mark Morris Institute. Dr. Linder has received speaker fees or research funding from Hill’s Pet Nutrition, Nestlé Purina PetCare, and Royal Canin, and has provided professional services for Mark Morris Institute." -Tufts Petfoodology

A review of veterinary teaching hospital records showed an incidence of DCM of 0.4% of the dogs seen. Based on an estimated population of 77,000,000 dogs in the United States, we would expect over 300,000 dogs to be diagnosed with DCM at this incidence rate. Yet the FDA released a public statement incriminating pet food based on a mere 560 cases. There was no science or research to back their statement. 

We do know that diets low in protein, taurine, and sulfur-containing amino acids methionine and cysteine (such as diets designed to manage urate stones) HAVE been associated with taurine-deficient DCM. When these diets are supplemented with taurine and L-carnitine, DCM clinical signs can be reversed. 

Dogs are capable of making taurine from amino-acid precursors, whereas cats do not perform this metabolism very efficiently. Because of this, feline diets have been supplemented with taurine for decades. Prior to the addition of taurine to cat food, many cats were diagnosed with dilated cardiomyopathy secondary to taurine deficiency. 

The number of Golden Retrievers with DCM has been increasing, raising the question of a genetic propensity toward disease. Recent studies have noted Golden Retrievers may be at risk for developing DCM but have failed to identify a definitive causal relationship between diet, taurine, and cardiac function. Differences in measuring taurine concentration also play a role: the relationship between whole blood taurine, plasma taurine, and cardiac muscle taurine concentrations remains unknown.

Many nutrients other than taurine are important for ideal heart health, including carnitine, thiamin, copper, vitamin E, selenium, magnesium, choline, and potassium. A review of the current literature reveals faults within DCM studies in dogs, including sampling bias, inconsistencies in sampling parameters, too many variables, and lack of complete data for case studies on DCM and known genetic predisposition in certain dog breeds. Small sample sizes and overrepresentation of breeds are commonplace in recent DCM studies. Studies involving multiple breeds and larger sample groups are warranted to better understand if relationships exist between potential etiologies (such as diet) and the development of DCM for the overall dog population.

On June 27, 2019, FDA released an updated list of dogs affected by DCM. Of the 305 dogs listed, 73% were breeds with known genetic predisposition for DCM. Also, 61% of the dogs included had other diseases which may have contributed to cardiac disease, including hypothyroidism, Lyme disease, and mitral valve degeneration. It is impossible to implicate specific types of dog food as being a causative factor when the data is already skewed.

Boutique diets, defined as produced by a small manufacturer, have been implicated in association with DCM. However, when the FDA report is broken down into which pet food manufacturers made the called-out diets, 49% of the brands listed were made by one of the six largest pet food manufacturers in North America. Given that almost half of the brands listed on the FDA report on June 27, 2019, are not manufactured by boutique pet food companies, it is unlikely that an association can be made to DCM. This did not stop veterinarians or the FDA from incriminating smaller pet food manufacturers, resulting in huge losses in revenue and jobs for many of those companies. 76% of the proteins listed in the FDA report included chicken, beef, pork, lamb, salmon, turkey, and whitefish, which are NOT exotic proteins that FDA labeled as problematic. 

A study performed at the University of Illinois in which dogs were fed a diet with 45% legumes (peas, lentils) showed no differences in plasma amino acids (taurine, carnitine) from dogs fed diets without legumes. Although FDA has called-out grain-free diets and implicated legumes as causative agents of DCM, this study shows no relation. 

Many pet owners have been made to feel guilty for feeding what they considered to be higher-quality diets. Unfortunately, there is no basis for this. The pet food and veterinary communities rushed to a conclusion that has no support. Our pets need MEAT in their diets to maintain good health. Balanced diets are important in ensuring that all nutrients are provided for optimum health and longevity.