Grain-free dog foods linked to fatal heart condition
DULUTH — A move to boutique dog foods, often billed as grain-free and filed with unique ingredients such as peas, chickpeas, lentils, sweet potatoes and potatoes, may be contributing to dogs across the U.S. dying of heart disease, the U.S. Food and Drug Administration reports.
The issue first surfaced one year ago when the FDA warned that there may be an increase in dogs dying from dilated cardiomyopathy, also known as DCM or canine heart disease, which can result in congestive heart failure.
The disease, which in the past had been considered genetic in some large breeds such as golden retrievers, in recent years started showing up in several other breeds. The FDA last year first hinted at a link between the disease outbreak and so-called grain-free dog foods that have become popular in recent years.
Flash forward one year and the FDA on Thursday, June 27, updated its warning, saying its ongoing investigation of the issue appears to point to those unique ingredients as the culprit. The FDA also noted that the problem is impacting cats to a lesser degree. It’s suspected that the ingredients are spurring a deficiency in an amino acid called taurine and that deficiency is causing the heart disease. FDA officials say the exact cause of the increased dilated cardiomyopathy remains unclear and that "there are other causes of DCM other than taurine deficiency."
But the agency warns pet owners that “the common thread appears to be legumes, pulses (seeds of legumes) and/or potatoes as main ingredients in the food. This also includes protein, starch and fiber derivatives of these ingredients. ... Some reports we have received also seem to indicate that the pets were not eating any other foods for several months to years prior to exhibiting signs of DCM.”
On Thursday the FDA updated its advisory on the DCM outbreak, naming 16 pet food brands that have been linked to 560 cases of dilated cardiomyopathy in dogs with 119 deaths between 2014 and April 2019. There have been 14 cases in cats with 5 deaths.
In nearly all of the cases the dogs ate dry food. More than 90 percent of the sick dogs' diets were grain-free and 93 percent had peas and/or lentils, the FDA said.
The FDA said the following brands of dog food were associated with cases of dilated cardiomyopathy. The number of known, reported DCM cases linked to that brand are also listed:
Taste of the Wild: 53
Earthborn Holistic: 32
Blue Buffalo: 31
Nature’s Domain: 29
California Natural: 15
Natural Balance: 15
Nature’s Variety: 11
Rachael Ray Nutrish: 10
Julie Churchill, professor of Veterinary Nutrition and Associate Medical Director of the University of Minnesota's School of Veterinary Medicine and a board-certified DVM nutritionist, said she would tell dog owners to stop feeding the boutique dog foods with the unconventional ingredients immediately.
"I am very risk-averse, in my personal life and in my practice. So if there is no health benefit, and I've been firm for years that grain-free offers no health benefit, and now there is a potential risk, why take that risk?" Churchill said.
"There's been sort of a quest or craving (by pet owners) for grain-free diets, mostly due to unsubstantiated marketing efforts, that has really set us up for where we are now,'' she said, noting dog owners have sought out "alternative'' dog foods in recent years in effort to help their dogs feel better, lose weight or shed an allergy that "probably isn't food-related anyhow."
Churchill said the actual numbers of DCM cases is probably much higher than the FDA reports, with most cases likely unreported, because there is often little or no advance warning to pet owners when a dog is afflicted.
"Oftentimes we've seen very subtle signs at first until suddenly it's respiratory distress, cough or an abnormal rhythm and then death. There often aren't very many signs until you have a developed disease,'' Churchill said. But she also offered hope. "If we can intervene early enough, and we get the diet changed, we have seen successes'' and dogs that recover, she said.
DCM is a disease of a dog’s heart muscle and results in an enlarged heart. As the heart and its chambers become dilated, it becomes harder for the heart to pump, and heart valves may leak, which can lead to a buildup of fluid in the chest and abdomen — congestive heart failure. If caught early, heart function may improve in cases that are not linked to genetics with appropriate veterinary treatment and dietary modification.
The FDA is warning pet owners to consult with their veterinarian before rapidly changing a dog’s diet.
Several of the listed manufacturers have battled back in recent days, saying the FDA's warning is premature and that only a tiny fraction of the dogs that eat their foods ever acquire DCM. The manufacturers say their products are safe and that it's been known for years that DCM is genetic in some dogs.
The Pet Food Institute, a trade group that represents nearly all pet food and treat makers, said it has consulted with nutritionists, product safety experts and veterinarians for more than a year in trying to determine if there's a link between diet and DCM. "This is a complex issue with many factors requiring scientific evaluation," Dana Brooks, the group's president and CEO, said in a statement. The trade group said the FDA "has not identified any established link between certain ingredients and incidents of DCM"' and that "millions of dogs eat and are thriving on grain-free dog food" with no sign of DCM
Valencia, Calif.-based Zignature said it will keep making and selling its dog food despite the FDA warning.
“As no one has been able to determine if or what the association may be between a dog’s diet and this rare cardiac condition, we believe it’s important that we continue to serve the millions of dogs that thrive on our diets,’’ the company said in a statement.
In a statement released after the FDA warning was issued, Edmonton-based Champion Pet Foods said the federal agency so far has offered “no causative scientific link between DCM and our products, ingredients or grain-free diets as a whole and it is unfortunate that the release of incomplete information is causing confusion among Pet Lovers about the food they purchase for their pets and the diets they follow.”
The company added that its own “third-party internal studies found no link between our high-quality pet food products and any of the other physical characteristics that correlate to DCM."
While the overall number of dogs impacted is small out of some 77 million dogs across the U.S., the correlation between DCM heart disease and diet spurred the FDA action. One puzzling aspect of the recent spike in DCM cases — the FDA called it unprecedented — is that they have occurred just in the last few years. The FDA said it is working with the pet food industry to better understand whether changes in ingredients, ingredient sourcing, processing or formulation may have contributed to the development of DCM.
The FDA says it stopped short of recalling the products due to the lack of scientific link between diet and DCM but that it had an obligation “to be transparent with the pet-owning public regarding the frequency with which certain brands have been reported.”
Advice from the FDA: Call your vet
The FDA suggests that, if your dog is showing possible signs of DCM or other heart conditions, including decreased energy, cough, difficulty breathing and episodes of collapse, you should contact your veterinarian. Your veterinarian may ask you for a thorough dietary history of all the foods, including treats, the dog has eaten. The average age of dogs affected was 6.6 years and the average weight was 67.8 pounds. Also consult with your veterinarian before rapidly changing your dog’s diet.