Grain-free dog food is not medically necessary for the vast majority of dogs, and the FDA has been investigating a link between grain-free diets, particularly those high in peas and lentils, and a serious heart condition called dilated cardiomyopathy (DCM). Here is what pet owners need to know before choosing a grain-free diet.
The Grain-Free Gamble
When the grain-free movement started gaining popularity, corn was removed from many diets and replaced, often, with peas and lentils. Ironically, while there is no data supporting corn being harmful, there is a meaningful and still-unexplained association between these legume-heavy diets and DCM (dilated cardiomyopathy), a potentially fatal heart condition in dogs not genetically predisposed to the disease.
The biography of grain-free food and the pet food industry is entertaining if nothing else. It starts in the early 2000s, when high-protein, gluten-free eating lifestyles (ex. Atkins) became popular in the United States. Like many things, we tend to anthropomorphize, or translate what makes sense for humans into something that also makes sense for animals – in this case, our pets. The vision of wolves and tigers being direct relatives to Fido and Fluffy only supported this theory. The melamine scandal in 2007 (thousands of pets got sick or died when Chinese wheat was contaminated with the toxin melamine) only added to the fear of feeding grains to our pets. Thus, the perfect setting was set in the mid-2010s for pet food makers to swoop in and create a whole new market of grain-free diets.
Enter Legumes
The question, as pet food companies went grain-free, was then what to replace the grains with – what would provide energy density, bind kibble, and carry moisture as effectively as corn and wheat? Enter potatoes, sweet potatoes, and, most popular, legumes (ex. peas, lentils, chickpeas) to the story. Legumes became the star of the show, providing protein and allowing less expensive meat to be used for dog and cat food, while meeting protein standards and still being palatable. Very quickly, as often happens, starting around 2007, lobbyists became involved, actively influencing pet food manufacturers and increasing the use of legumes in pet food from nearly nothing to an estimated up to 20% of the US legume market within ten years.
Trouble on the Horizon
In 2018 there was a ripple – a hint of things to come. The FDA announced it was investigating a potential link between grain-free diets and a serious heart condition called dilated cardiomyopathy (DCM), a potentially fatal disease where the heart muscle weakens and the chambers enlarge. DCM was appearing in breeds not considered genetically predisposed to it. Upon further investigation, there was a trend in these dogs, and it was a grain-free diet – with over 90% of foods implicated being grain-free, and 93% containing peas or lentils. Potatoes and sweet potatoes appeared in 42% of cases.
More Questions Than Answers
To this day, the exact cause and effect is not fully understood between grain-free, lentil, or potato-containing food, DNA predisposition, and DCM. What we do know clinically is this: the association is real enough that it cannot be dismissed, grain-free diets are not physiologically or medically necessary for the vast majority of pets, and in many cases dogs showed meaningful cardiac improvement after switching away from grain-free diets, though outcomes varied. Ultimately, the risk is not worth it for zero benefit.
The grain-free and DCM question is one part of the full picture we cover in our complete pet food label guide.
Curious why corn got blamed in the first place, before the industry moved to legumes? Read Is Corn Bad for Dogs? The Truth Behind the Filler Myth.
Have questions about your pet’s specific diet? Our veterinary team is happy to walk through your pet’s current food at any wellness visit. Schedule a visit with Healthy Paws Animal Hospital.