The FDA recently released an update on its investigation of diet-related canine dilated cardiomyopathy (DCM), which began in July of last year. Out of the 325 dogs diagnosed with DCM from January 2014 to November 2018, 276 have been reported since the FDA first announced its investigation. (There were only 10 cat cases reported.) The link between grain-free and specialty foods and this deadly disease is still unclear. But the data released so far suggests that pet food manufacturers need to take a closer look at their formulations.  

The questionable ingredients

Dry food formulas made up the majority (269) of the DCM reports. Dogs in 196 reports were fed a single diet (did not switch between or eat multiple food products). The FDA analysis of those formulas found that approximately 90% were labeled “grain-free.” Some foods included in the other 10% were vegan, vegetarian, or contained brown rice.

The most prevalent ingredients included:

  • Peas (92%)
  • Lentils (53%)
  • Potatoes (32%)
  • Sweet Potatoes (28%)
  • Chickpeas (28%)

It would be premature to eliminate these ingredients from pet food products, as the findings are far from conclusive at this point. Peas, lentils, potatoes, and other non-meat protein and carbohydrate sources are standard in most grain-free formulas. Legumes and potatoes have proven beneficial qualities, and there is currently no solid evidence to suggest that they cause DCM. But Dr. Greg Aldrich, who presented these findings at the 12th Annual Pet Food Conference, warns in Pet Food Industry that these ingredients shouldn’t be overly abundant in formulations. Too much can upset the food’s nutritional balance and affect amino acid absorption.

Diets examined in the analysis included a wide variety of animal protein sources. No source stood out among them as potentially problematic, but Aldrich says in Pet Food Processing that many diets with single protein sources would be more effective with complementary proteins. And some meats like rabbit, buffalo, salmon, and kangaroo do not yet have enough research behind them to determine how they contribute to overall pet health. Aldrich cautions against introducing new, risky ingredients to the industry ahead of critical data collection and food trials.

The growth of specialty pet foods

“Some pet foods in the market have become overly ambitious about winning the horse race with the next new thing,” Aldrich adds. “We need to get the message to the retailers and consumers that these extremes in ingredient composition may have consequences.” He stresses the need for nutritional balance, something that’s difficult to ensure in formulas with unconventional ingredients.

Tufts nutritionists note that small, inexperienced pet food manufacturers could be part of the problem. These companies often lack the nutritional knowledge, stringent quality control, and testing capabilities that help larger, established manufacturers meet the requirements of a healthy, balanced diet.

It’s easy to market to pet owners who want their dogs and cats to taste the latest trend. Often, they’re seeking out remedies for common health concerns like allergies, obesity, digestive issues, and joint health. And they’ll buy food that advertises itself as a solution. As a result, grain-free has taken a back seat to labels like vegan, raw, dehydrated/freeze-dried, and human-grade. If pet food processors don’t approach these diets carefully and deliberately, the DCM investigation won’t be the last of its kind.  

Taurine is a concern, but not a major player

It’s still uncertain whether the amino acid taurine has any role in the recent DCM reports. Taurine deficiency has been linked to a small number of DCM diagnoses, particularly among Golden Retrievers. However, Dr. Lisa Freeman of Tufts University advises against increasing taurine supplementation, as “most dogs being diagnosed with DCM do not have low taurine levels.” She says 90% of the patients tested at Tufts had normal taurine levels.

But the majority of those patients were also eating what Freeman refers to as “BEG” diets. This includes diets from boutique companies, diets that contain exotic ingredients, or grain-free formulas. Some of the patients even improved after switching to conservative formulas. This means it’s likely that specialty diets have some influence over DCM. But it will take more time and research to pinpoint the problem.  

No cause for alarm

But the DCM cases shouldn’t lead to panic. After all, 325 is a small number considering that roughly 22 million dogs are eating grain-free food in the U.S. DCM is not a new issue, but one that veterinarians say is quite common. It accounts for 10% of all heart-related diseases among dogs. Large dogs (over 30 lbs.) and older dogs (over 4 years) are already at risk. So are specific breeds like Great Danes, Cocker Spaniels, and Irish Wolfhounds. Doberman Pinschers are genetically 60% more likely to develop DCM.

Grain-free diets may not be to blame for the DCM outbreak, as there are several other possible factors. The FDA reports that the Veterinary Laboratory Investigation and Response Network is looking into environmental influences and collecting data from necropsies. Only time will tell if any additional findings surface.

What the pet food industry can do now

Freeman suggests that pet food manufacturers work with full-time, qualified nutritionists. And if they don’t already have proven quality control measures in place, they should take steps to implement better safety and testing practices. Ideally, all formulas should go through the Association of American Feed Control Officials (AAFCO) feeding trials. “If AAFCO feeding trials are not conducted,” Freeman writes, “the manufacturer should at least ensure their diets meet AAFCO nutrient profiles through analysis of the finished product (rather than by predicting they meet the profiles based only on the recipe).”

Until the investigation unearths more conclusive data, pet food manufacturers should reexamine the quality and sources of their ingredients, their processing practices, and their formulations. Especially if there have been changes among these within the past few years. They should report any findings and insights to the FDA as the investigation continues.