It was only by accident that veterinarians discovered that Martha Martin’s beloved black laboratory, Sophie, had developed a potentially fatal heart disease.
The dog was being treated for a snakebite when the vet found an abnormal heart rhythm and ordered an echocardiogram.
“I’ll never forget when the vet turned to me and asked if Sophie would get a grain-free dog food,” remembers Martin. “I felt like an idiot hit me.”
The 7-year-old bitch had consumed the same brand of grain-free dog food since childhood – just like Martin’s other dog, Bailey. An echocardiogram showed that 9-year-old Bailey also had the beginnings of dilated cardiomyopathy (DCM).
Martin switched both dogs to a different food that contained grain in hopes that this might help heal their hearts.
In the more than two years since the Food and Drug Administration first warned dog owners about heart failure in their animals, which can be linked to grain-free pet food, more than 200 dogs have reportedly died from the disease, and scientists are trying still figuring this out why.
Research has shown that ingredients used in dog food instead of grains could be involved in the development of DCM, a disease in which the heart grows larger and it weakens. Some breeds of large dogs are genetically susceptible to DCM, including Great Danes, German Shepherds, and Doberman pinschers, according to the VCA Animal Hospitals.
“Most of the diets associated with reports of non-hereditary DCM contain legume seed components, also known as ‘legumes’ – such as peas and lentils – and are high on their ingredient lists,” said FDA spokeswoman Monique Richards . “Although soy is a legume, we haven’t seen any signal for this ingredient.”
The problem can be the amount of ingredients that are used in non-traditional dog foods.
“Legumes, including legume ingredients, have been used in pet foods for many years. There is no evidence that they are inherently dangerous, but rather data that has been reported has been analyzed [the FDA] indicates that pulse ingredients are used in many “grain-free” diets in greater proportions than most cereal formulas, “Richards said in an email to NBC News. “The FDA has asked pet food manufacturers to provide diet formulations so that we can better understand ingredient proportions in commercial diets and possible relationships with non-hereditary DCM.”
However, it’s not clear if it’s simply the amount of these ingredients in the food, said Dr. Bruce Kornreich, a veterinary cardiologist in the Department of Clinical Sciences at Cornell University College of Veterinary Medicine.
“It can’t just be what’s on the diet,” he said. “It could be where it comes from or how it is processed.”
A recent study showed that dogs with DCM who consumed non-traditional dog food were more likely to have improved condition and lived longer when switched to traditional dog food along with their heart medication.
“Our study was a retrospective look at 75 dogs with DCM over a period of just under five years,” said study co-author Dr. Lisa Freeman, veterinary nutritionist and professor at the Cummings School of Veterinary Medicine at Tufts University. “One of the new findings in our study was that the number of dogs with DCM increased significantly over time. This surge began even before the first FDA warning. “
To date, the FDA has not recommended the recall of grain-free products or declared certain pet food products unsafe.
The Pet Food Institute responded in a statement to NBC News: “Nutritionists, veterinarians and product safety specialists from PFI members have studied dilated cardiomyopathy (DCM) in depth to better understand whether there is a link between DCM and diet in dogs that are not genetically predisposed to the disease. Drawing on historical and current scientific analysis and published articles, PFI members devote thousands of hours to improving our understanding of DCM and its causes in order to promote pet welfare. “
Millions of dogs in the U.S. regularly consume grain-free food with no reported problems, said Dana Brooks, CEO and president of the Pet Food Institute, via email.
“Current research suggests that a variety of factors can influence the development of DCM in dogs,” she wrote. “The number of DCM reports submitted suggests that if diet is a factor, it may be under several elements such as the dog’s individual physiology.”
Typically, pets with DCM have hearts that get bigger and their contractions weaker over time, said Freeman of Tufts University. But the hearts of dogs that were switched to traditional dog foods showed improvement.
“They lived significantly longer than those without a change in diet,” she said.
The experience of Martin’s dogs reflects this. She switched Sophie and Bailey to a cereal meal. Bailey immediately began to improve and soon had normal EKGs. But Sophie wasn’t so lucky. “Every visit to the cardiologist showed that she was worse,” said Martin. “The cardiologist told me she didn’t think she could recover. I was down. “
Martin had noticed that Sophie seemed to have digestive problems too, and had foreshadowed her pet switched to a food made by the same manufacturer, which was aimed at dogs with intestinal problems.
“She lived on it,” said Martin. “A few months later we went to the cardiologist and expected more bad news. Lo and behold, she had turned around and was walking in the other direction. Our vet loved it. “
The number of DCM cases reported to the FDA has increased since its warnings were published in 2018. As of July 31, 2020, the agency had received more than 1,100 reports of DCM in dogs, of which 280 died from the disease. There have also been reports of DCM in cats. Of the 20 cases in cats, approximately 13 died.
The FDA, along with experts from science, industry, and veterinary medicine, practically met in September at a science forum hosted by Kansas State University to investigate the possible causes of non-hereditary DCM in dogs.
In November, Dr. Steven Solomon, director of the FDA Center for Veterinary Medicine, visited the Kansas State Forum on the FDA website.
“The best thing you can do as a pet owner is to speak to your veterinarian about your dog’s nutritional needs based on their health and medical history,” he wrote.
Kornreich at Cornell University has sympathy for owners whose pets have DCM.
“It’s sad,” he said. “You have to tell people that the choice they have made about treating their baby has an impact on their health. You tried to do the right thing. “