In July 2018, the US Food and Drug Administration (FDA) announced that it was investigating a potential link between heart disease in dogs and the consumption of grain-free pet food.

The announcement said, in part: “We are concerned about reports of canine heart disease, known as dilated cardiomyopathy (DCM), in dogs who ate certain pet foods containing peas, lentils, and other legumes or potatoes as their main ingredients.”

The FDA last week released an update on their investigation. And this time, they name names.

As part of their investigation, the FDA has now identified 16 brands of dog food which had the most frequent reported cases of DCM. The top three brands, according to the FDA, are Acana, named in 67 reports; Zignature, named in 64; and Taste of the Wild, named in 53s.

The FDA first received sporadic reports of DCM as early as 2014, but most of the reports were submitted after the agency’s first announcement a year ago July.

Between January 1, 2014 and April 30, 2019, the FDA received 524 reports of DCM Approximately 222 of these were reported between December 1, 2018 and April 30, 2019, after the FCA called for veterinarians to submit cases of diagnosed DCM for review. Some of these reports involved more than one affected animal from the same household.

Since then, the FDA’s Center for Veterinary Medicine (CVM) has taken a multi-pronged approach to the investigation. CVM veterinarians, nutritionists, pathologists, and epidemiologists are collaborating with several sectors of the animal health world to collect and evaluate information about those reported DCM cases and the diets pets ate prior to becoming ill.

A key partner in the investigation is the Veterinary Laboratory Investigation and Response Network (Vet-LIRN), a collaboration of government and veterinary diagnostic laboratories.

Most dogs in the US have been eating pet food without apparently developing DCM. It’s not known how commonly dogs develop DCM, but the increase in reports to the FDA signal a potential increase in cases of DCM in dogs not genetically predisposed.

A genetic predisposition for DCM is typically seen in large and giant breed dogs, such as Great Danes, Newfoundlands, Irish Wolfhounds, Saint Bernards and Doberman Pinschers. The disease is less common in small and medium breed dogs, except American and English cocker spaniels.

However, recently reported atypical cases have included golden and Labrador retrievers, a whippet, a Shih Tzu, as well as mixed breeds.

Early reports from the veterinary cardiology community indicate that the dogs in those cases consistently ate foods containing peas, lentils, other pulses (legume seeds), or potatoes as primary ingredients in their main source of nutrition. The length of time they were on those diets ranged from months to years.

In order to address the confusion, Lisa Freeman, DVM, PhD, DACVN, a board-certified veterinary nutritionist and a professor at Cummings School of Veterinary Medicine at Tufts University, got together with several of her cardiologist colleagues and published an article in the December 2018 issue of the Journal of the American Veterinary Medical Association that summarized the current medical understanding of diet-associated DCM at that time.

Freeman told NEWStat that, “while many people have focused on grain-free diets being associated with this problem, other diets may put dogs at higher risk as well. I call the suspected diets ‘BEG’ diets—boutique companies, exotic ingredients, or grain-free diets. It’s also important to be aware that vegetarian, vegan, and raw meat diets are not immune.”

Because so many products contained peas and/or lentils, The FDA created a new category for “peas and/or lentils”

Despite the number of DCM cases reported, the problem might be even worse than some believe. the FDA wrote: “We suspect that cases are underreported because animals are typically treated symptomatically, and diagnostic testing and treatment can be complex and costly to owners.”

According to recheck echocardiograms in the medical records, some pets with DCM improved after veterinary treatment, diet change, and taurine supplementation, while others improved with appropriate veterinary care and diet change alone.

The agency has not asked the pet food companies to recall their products. “We have shared case report information with these firms so they can make informed decisions about the marketing and formulation of their products,” the FDA wrote.

Another puzzling aspect of the recent spike in DCM cases is that they have occurred just in the last few years. The FDA is working with the pet food industry to discover whether changes in ingredients, ingredient sourcing, processing, or formulation may have contributed to the development of DCM.

The investigation remains ongoing.

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