At the end of June, the FDA released an update on its investigation into a spike in reported cases of Canine Dilated Cardiomyopathy, or DCM. This investigation and report have caused many pet owners to worry about whether the food their dogs are eating could cause heart disease.

The investigation is ongoing, and the results are not conclusive. But they do point to multiple factors, not a simple link between diet and heart disease or, more specifically, grain-free kibbles and heart disease.

The investigation was triggered by unusually high numbers of cases of DCM reported in 2018 and early 2019, a total of 320 reports in 2018 and 197 in January through April 2019. For comparison, from 2014 through 2017, the FDA received a total of 7 reports. These numbers include cats and dogs, though very, very few are cats. Since some of the reports concern multiple pets in a household, the total number of affected animals is 560 dogs and 14 cats. To provide context, it’s important to note that these 560 dogs are from a population of 77 million pet dogs in the U.S. It’s a very small number of cases, yet the spike was unusual, and I, for one, am glad to see researchers digging into this.

The most commonly affected breeds are golden retrievers (95), mixed-breed dogs (62), and Labradors (47).

The FDA report offers a lot of information, and here’s where it gets interesting. Most of the dogs affected are older, with a mean of 6.6 years; and since most are also larger (mean weight of 68 lbs.), many are considered “senior.”

The FDA report provides information about the dogs’ diet. Nearly all of the dogs ate an exclusively kibble diet (452 out of the 515 reports). The foods named, with Acana and Zignature topping the list, are all high-end foods with multiple grain-free formulas. Several of the brands named in the report are quality brands that appear on the Whole Dog Journal’s list of approved dog foods.

2019_WDJApprovedDryDogFoods

It’s unlikely that multiple high-end brands of dog food all developed the same nutritional deficiency, suddenly and simultaneously, in 2018. What’s more likely is that people started paying more attention to symptoms their dogs were exhibiting and, rather than simply attributing them to age, got them checked out. The interesting detail that many of the dogs are eating expensive dog food hints that these dogs might live with people who have the means and desire to pamper their pets a bit — just the sort of dog owners who are also more likely than the average to shell out for annual bloodwork and one- or twice-yearly senior pet exams.

A correlation the FDA is looking closely at is whether the high proportion of grain-free foods using large amounts of peas and/or lentils had anything to do with the DCM. The reported foods also contained a large variety of animal proteins, with chicken, lamb, and salmon topping the list. There are so many other variables, though, that drawing a connection between either the animal or vegetable protein sources and the heart disease is tough. For one, the millions of dogs eating those same foods who are not showing any signs of DCM. For another, it’s very rare that a dog eats one kibble and one kibble only — no treats, nothing scavenged on a walk, nothing slipped to him at the dinner table. The FDA is interviewing some owners to determine whether exposure to other things — plants, chemicals — could be a factor.

It’s possible that further study will find a connection. One area researchers are considering is whether large amounts of pea or lentil protein interferes with dogs’ ability to digest necessary minerals or amino acids, like taurine.

I don’t think panic is warranted. I also don’t think boycotting the named brands (or all grain-free foods) is justified. I do have some common-sense suggestions, though, for worried pet owners: Switch up your dog’s food.

Anyone who eats the same diet, day in, day out, for months or years is bound to have some nutritional deficiencies, especially a diet as highly processed as kibble. No one food can provide everything any dog needs. The old “advice” about not switching dog’s food and how anything new will upset their stomachs is bunk. Sure, if your dog has eaten the same kibble for 7 years and you suddenly switch to something radically different, your dog is likely to have digestive issues for a while. If your dog has a lot of food sensitivities, again, proceed cautiously. But most dogs can switch pretty easily. I usually mix the last couple pounds of a bag of an old food with the new food, giving the dog a week or more to transition.

Some manufacturers encourage switching among their formulas. I’d go a step farther and switch companies and formulas to ensure that over a year or so, your dog gets a few different proteins and formulas. They all add different mixes of vegetables, minerals, and other supplements. With Cali, I mix kibble with frozen raw food (one meal of each per day). She also gets salmon oil, a probiotic and digestive enzyme supplement, a joint support supplement, and lots of fresh fruit, vegetables, eggs, sardines … OK, so she’s a little spoiled. So?

Even if you don’t want to go that crazy, switching foods every couple of bags could give your dog some variety and a better mix of nutrients over time.

In addition, make sure your dog has regular exams and bloodwork. Raise your concerns with a vet you trust and, if your dog is showing signs of DCM, such as coughing, trouble breathing, or lethargy, get a checkup.