Popular Grain-Free Dog Foods May Be Linked to Heart Disease

Bison and chickpeas. Wild boar and sweet potatoes. Kangaroo and lentils.

These are just a few of the spectacularly popular selections of “grain-free” dog food that have deluged the pet food market in recent years. Dense with exotic proteins, teeming with legumes favored by health-conscious humans, they are promoted as delicious as well as nutritious — better for gluten-sensitive bellies, closer to the ancestral, protein-rich diets of the Yorkie’s savage forebears.

But earlier this month, the Food and Drug Administration announced that it is investigating a link between these diets and a common type of canine heart disease.

The condition is dilated cardiomyopathy, or D.C.M., in which the heart weakens and becomes enlarged. Symptoms include fatigue, difficulty breathing, coughing and fainting. Some dogs can abruptly go into heart failure.

D.C.M. is typically seen in large breed dogs that have a genetic predisposition for it, like Doberman pinschers, Irish wolfhounds, boxers and Great Danes. But CVCA, a practice of 19 veterinary cardiologists in the Baltimore-Washington, D.C. area, alerted the F.D.A. that it has been seeing D.C.M. among other breeds, including golden retrievers, doodle mixes, Labrador retrievers and Shih Tzus.

The common factor was a diet heavy in peas, lentils, chickpeas and potatoes — carbohydrates typically intended to replace grains.

Other veterinary cardiologists have also noticed the phenomenon. “The first clue for us was when we saw a household with two unrelated miniature Schnauzers with D.C.M.,” said Darcy Adin, a veterinary cardiologist who teaches at North Carolina State University’s College of Veterinary Medicine. “They were both eating the same boutique, exotic protein, grain-free diet.”

Her team has documented 36 dogs with suspected nutritional D.C.M., including poodles and dachshunds.

The possibility that expensive food, lovingly chosen, could make one’s adored pet devastatingly ill is sending shudders through dog owners.

“Don’t panic,” said Martine Hartogensis, a veterinarian who is deputy

director for the Office of Surveillance and Compliance in the F.D.A.’s Center for Veterinary Medicine.