It started with a late-night cough. “He was otherwise fine, but . . . something was weird and different,” said Verai Ramsammy, who was worried about her miniature Schnauzer, Louie. She was a meticulous dog person, the kind who bought special food for her pets. She made a veterinary appointment just to be safe.

Within months, Ramsammy’s second dog, Mico, fell ill with the same problem. This made Ramsammy’s veterinarians sit up. The two dogs, both mini-Schnauzers, were unrelated. Their only connection was the home in which they lived.

Their cases helped link a serious, sometimes fatal, heart condition with the latest dog food fad. As more cases were reported from around the country this year, veterinarians and the Food and Drug Administration began investigating a potential link between boutique, grain-free diets and a heart disease called canine dilated cardiomyopathy (DCM), which had been known primarily as a genetic disorder. This summer, the FDA issued a caution against grain-free diets. Since then, many more reports have poured in.

Three weeks after Louie’s minor cough and a bronchitis misdiagnosis, Ramsammy said, the 19-pound “typical barky Schnauzer” with a rough black coat stopped eating and had trouble breathing.

“It was bad. It just progressed so quickly,” said Ramsammy, an ICU physician who was no stranger to emergencies. She rushed him 1 1/2 hours away to the North Carolina State College Veterinary Hospital in Raleigh for advanced care.

After a sleepless night at the hospital with Louie, Ramsammy saw Mico collapse outside the hospital. “He had this spastic movement and then he scrambled to his feet,” she said. She assumed the stress of travel and hospital visits was getting to the dog, the way it was getting to her.

Inside the hospital, Louie’s heart was enlarged and fluid was filling his lungs. “He was dying,” Ramsammy said, “there was nothing I could do.” Ramsammy held him as he died, one month after his symptoms began.

Three months later, Mico, a soft-haired, salt-and-pepper-colored Schnauzer, was collapsing more frequently. Darcy Adin and her veterinary team at North Carolina State found he was also struggling with an enlarged heart. The veterinarians put Mico on heart medication immediately. The dog was “on the verge of going into heart failure the way Louie did, and it’s just lucky they caught it in time,” Ramsammy said.

Canine DCM weakens the dog’s heart, Adin said, preventing it from pumping enough blood, so it enlarges to try to compensate. After a certain point, fluid backs up from the heart into the lungs causing congestion and coughing. Other symptoms of DCM include difficulty breathing, weakness and lethargy. It can eventually ” lead to congestive heart failure signs and, in some cases, sudden death,” Adin said.

Across the country at the University of California at Davis, Joshua Stern, another veterinary cardiologist, started to see surprising signs of heart disease in his golden retriever patients. Multiple veterinary groups, working independently at first, started to notice this disturbing trend. The world of veterinary cardiology is small, with only around 200 specialists in the United States, Stern said. They alerted the FDA. Together, they began compiling cases and investigating environmental conditions that might affect unrelated dogs within one household. The vets started to find that many of the sick dogs had been on grain-free diets, high in legumes, leading up to their illnesses.

“There was a lot of guilt that it was something I’d done, but I had no idea what it was,” Ramsammy said.

On July 12, 2018, the FDA put out a cautionary statement. The FDA report stated that canine DCM was typically caused by a genetic predisposition in large breed dogs such as Great Danes and Newfoundlands. The recent cases included “Golden and Labrador retrievers, a Whippet, a Shih Tzu, a Bulldog and Miniature Schnauzers, as well as mixed breeds. Early reports . . . indicate that the impacted dogs consistently ate foods containing peas, lentils, other legume seeds or potatoes as main ingredients,” said the report. The length of exposure to the diet ranged from months to years.

Before releasing the cautionary statement, the FDA had received 30 reports of dogs affected with DCM and linked to a grain-free diet, and the veterinary cardiologists had collected about 150 cases. Martine Hartogensis, the FDA Deputy Director of the Center for Veterinary Medicine, said that since the statement, the FDA has received reports of an additional 120 dogs sickened with DCM, most involving a grain-free diet. At least 24 dogs have died of the condition.

The FDA is still investigating the link with grain-free pet food. An FDA press officer stated in an email that it “has not determined that the pet food is causally associated with these pet illnesses and deaths.” No dog food has been recalled.

“If dozens of babies were getting deathly ill eating a formula, that formula would have been pulled from the shelf a long time ago,” Stern said. He has identified 24 golden retrievers affected by this issue over the last one to two years, compared with previous years of just one or two cases total.

The condition is linked to a taurine deficiency. Taurine is an essential amino acid that most animals, including humans, can create their own. Dogs get a lot of it from their diet. Chicken and beef are high in taurine, while rabbit, lamb, legumes, pea-protein and other ingredients found in some grain-free foods have little or no taurine. If items that are naturally low in taurine are placed in food formulas, they need to be supplemented with taurine, Stern said.

Big brands of dog food have the resources to test their dog food extensively in the lab and in feeding trials, Stern said. The FDA and federal law have mandated that pet food be safe and properly labeled. But in a statement to The Washington Post, the agency said, “It is the manufacturer’s responsibility to ensure that the animal food products it produces are safe . . . The FDA has the authority to take action when animal food is unsafe or if a label is inaccurate or misleading.” The FDA “does not have premarket approval authority” for pet food formulas before the bags of kibble appear on store shelves.

There are important things to look for on dog food labels . For example, the phrase “complete and balanced” is a specific term meaning that the dog food has met the minimum requirements set forth by the Association of American Feed Controls (AAFCO). While it does not have regulatory authority, AAFCO monitors the sale and distribution of pet food as well as recommending nutrient profiles for cats and dogs.

Dog food trends may track with pet owner tendencies. Stern likened grain-free dog food to the cave man diet for humans. “As the push for raw ingredients and organic growing grew in the human market, it similarly grew in the pet market,” he said.

Stern said dogs do not need just the “chicken cutlet,” as some pet food advertises, even if this sounds more appealing to the average (human) American family. Byproducts on pet food labels are defined as organ meat, lungs, liver, etc. These are all great for dogs to eat, Stern said.

Some dog owners may think their dogs have allergies, but Stern and Adin said it’s important to know that the most common allergies for dogs are to not grains, but meat. Chicken is a common allergen for dogs. While a dog can be allergic to corn or wheat, it would be a very rare coincidence to find a dog allergic to all “grains.”

Dogs, unlike wolves, are omnivores and can consume up to 50 percent of their diet as carbohydrates. Verai Ramsammy had chosen a grain-free diet for her dogs based on a friend’s suggestion. She said of her reasoning at the time, “It’s probably like carbohydrates for humans, too much really isn’t healthy for them.”

“The truth is from a genetic perspective, dogs really aren’t that much like wolves anymore. Dogs evolved and so have their digestive tracts,” Stern said. “We’re not looking at a bunch of little wolves running around eating kibble.”

“I’m sitting here with my golden retriever’s head lying on my foot, and I don’t think she could be any further from a wolf,” Stern added.

The pet food industry response to the canine DCM increases has been varied. Mars Petcare, the manufacturers of brands like Pedigree and Whiskas, said: “We take any pet concern seriously. Along with the broader pet food industry, we are working with the FDA to better understand any potential link between ingredients and DCM.”

Verai Ramsammy fed her two mini-Schnauzers two flavors of California Naturals dog food (kangaroo and red lentil as well as venison and green lentil) before they got critically ill. The company posted a message on its website that it is out of business as of summer 2018. The website offers alternatives to their dog food: ” As you look to transition to a new food, please consider Nutro™ Limited Ingredient Diet, which . . . offers a range of grain-free recipes with 10 key ingredients or less, ideal for pets with food sensitivities.”

With dogs genetically predisposed to DCM, the condition is irreversible. But in these new cases, adding taurine to the dogs’ diet (and taking them off legumes) can reverse the disorder if caught early enough, said both Stern and Adin.

Mico is one such case. He has been on heart medications since May of last year and is doing very well, Ramsammy said. A typical monthly bill for Mico is $110 in medications.

“I told him he’s going to have to get a job” Ramsammy said.