Canine dilated cardiomyopathy (DCM) has been a hot topic in the pet food industry, the veterinary community, the press and among pet owners. While certain people may believe they know the root cause of recent cases, the reality is that no link or diet type has been proven to cause DCM in dogs.
For those of you who watch and follow Marvel Comics, you are likely familiar with this quote from Spiderman: “With great power comes great responsibility.” Now, you do not have to be a web-slinging superhero to know that this phrase also applies to people perceived as experts or academics, as well as to the press and others. When you have people who look to you as a source of truth, then it is your responsibility to support your statements with facts, not anecdotal data or fear-mongering.
Case in point: In 2012, ABC News chose to ignore the proper and common name of an ingredient, lean finely textured beef, and coined the phrase “pink slime.” Granted the term “lean finely textured beef” is not so consumer friendly nor romantic – but it is accurate. Lean finely textured beef is 100% beef recovered by a mechanical process (vs. hand carving) that efficiently and effectively separates lean meat from fat for ground beef.
Unfortunately, ABC News chose to call the meat pink slime, likely because that name would gain viewer ratings vs. educating the consumer properly. As a result, Beef Products Inc. (BPI) had to lay off 700 employees and lost customers, and ABC’s parent company, Walt Disney, settled a lawsuit with BPI to the tune of US$177 million.
In early June 2018, Lisa M. Freeman, DVM, Ph.D., D.A.C.V.N., a veterinarian and professor with the Cummings Veterinary Medical Center at Tufts University, wrote an article titled, “A broken heart: Risk of heart disease in boutique or grain-free diets and exotic ingredients.” She said cardiologists had noticed higher rates of DCM in Golden Retrievers and some atypical dog breeds.
Though no genetic testing or food analysis was conducted, the cardiologists drew a broad anecdotal conclusion “that the dogs were consuming boutique or grain-free diets, and diets with exotic ingredients – kangaroo, lentils, duck, pea, fava bean, buffalo, tapioca, salmon, lamb, barley, bison, venison and chickpeas,” Freeman wrote. “Even some vegan diets have been associated. It has even been seen in dogs eating raw or home-prepared diets.”
In July 2018, the Food and Drug Administration (FDA) announced they were investigating a connection between diet and canine heart disease. Following this announcement, Freeman made press appearances where she was quoted as saying, “I’m actually referring to them as BEG diets, or boutique, exotic ingredient and grain-free diets.” The term was reiterated in an article published in the Journal of the American Veterinary Medical Association (JAVMA), “Diet-associated dilated cardiomyopathy in dogs: what do we know?” in December 2018.
After almost a year of investigating the link of “BEG” diets to DCM, FDA provided an update on their investigation in June 2019. The update provided information on all the animals in reported cases, including breed, age, sex, foods consumed, diagnosis, etc. FDA also provided bar charts for protein sources involved in the cases that were tied to the investigation.
In addition, FDA reported all pet food brands named in DCM reports submitted to the agency. Unfortunately, they only graphed the top 16 brands, and this is what took over the headlines in the press. If the press and others took the time to actually review all the cases reported to FDA (submitted through April 30, 2019), they would have seen other brands like Purina ONE, Hill’s Pet Nutrition, Halo, V-Dog, Lotus and others. What is more important is that the majority of brands named in the report are not boutique brands and can be found in large pet specialty, grocery and mass market stores. Thus, the “B” in BEG is inaccurate and a misnomer.
For proteins, FDA noted “that animal protein sources in the reported diets varied widely, and many diets contained more than one protein source. The most common proteins in the reported diets were chicken, lamb and fish; however, some diets contain atypical protein sources such as kangaroo, bison or duck. No one animal protein source was predominant.”
Said differently: Of the cases investigated, 75% were common protein sources (chicken being No. 1), 24% were novel protein sources and 1% were vegetarian foods. In case you were wondering, kangaroo was only 9.3% of the total cases. Thus, the “E” for exotic in the acronym BEG is also inaccurate and a misnomer.
It is unfortunate that the term BEG is used to describe the potential issue with DCM. Maybe people leading the charge should have actual data versus anecdotal data; otherwise, this could be another pink slime incident. Also, maybe JAVMA should consider correcting or rescinding the December 2018 article – thus resulting in veterinarians diagnosing and reporting all cases of DCM and not just looking for ones tied to BEG diets.
From a nutritionist’s point a view, the “G” in BEG means nothing. What I do see is that the majority of foods implicated contain peas and lentils (93% of total cases) and are grain-free (91% of total cases). I also see that 88% of the foods implicated are dry foods and a negligible amount are wet (canned), raw, home cooked or freeze dried.
What people fail to recognize is that almost 10% of the report cases were grain based. Thus, having veterinarians focus on grain-free foods only will likely miss cases of dogs consuming grain-based foods made by larger companies. In other words, if you don’t look for it in all food types, you will not likely find the root cause. Thus, it makes one question if grain free (the G) is truly the issue, especially when the issue does not exist in the other food forms (wet, raw, home cooked or freeze dried).
In my opinion, this likely has nothing to do with legumes at all and most likely has to do with actual nutrients, like levels of total dietary fiber, soluble fiber and resistant starch, cysteine, methionine and taurine, and their availability. Most dry kibble contains more than 35% carbohydrates, heat resistant starches and soluble fiber since they are needed for the processing of kibble.
For example, we know that beet pulp decreases taurine status (due to increased excretion of bile acids containing taurine) and decreases protein digestibility (taurine precursors) in dogs. For those of you not familiar with beet pulp, it is a good source of both soluble and insoluble fiber and is commonly used in grain-based dog foods.
In short, if we continue to misinform the public and the veterinary community to look at only boutique, exotic protein and grain-free foods, we may never identify the root cause of these DCM cases, if one exists. The veterinary community should lose the mind-set that they are caused by so-called BEG foods. Instead, if signs of DCM do exist, veterinarians should go through the battery of tests to confirm the presence of DCM and report it regardless of what the dog is consuming.
Lastly, no studies to date have ruled out additional genetic predispositions, which could easily explain the presence of DCM with normal or high taurine levels. Historically, only certain breeds were known to be predisposed; however, maybe we are finding out other breeds may be at risk.
As nutritionists and scientists, we talk about all the cool things we can accomplish through knowing about the dog’s genome. Maybe it is time to look at the differences among healthy dogs, dogs with DCM caused by low blood taurine and dogs with DCM of unknown origin (i.e., normal or high levels of blood taurine)? Perhaps it has nothing to do with breed and has to do with the expression of certain genes that overlap in multiple breeds.