Study: Grain-Free Diet for Dogs Leads to Canine Heart Disease
University of California, Davis, veterinarians led a team that has found a link between some popular grain-free, legume-rich dog diets and a type of nutritional deficiency and canine heart disease known as taurine-deficient dilated cardiomyopathy. The study was recently published in the journal PLOS ONE.
Researchers found dogs eating some of these “boutique” diets are not making or maintaining enough taurine, an amino acid important for heart health. Taurine deficiency has been known for many years to lead to dilated cardiomyopathy, or DCM, a heart muscle disorder that can lead to congestive heart failure and death.
“I was surprised by how similar the diets being fed to the affected dogs were,” says lead author Joshua Stern, a veterinary cardiologist and geneticist at the UC Davis School of Veterinary Medicine. “I was shocked to see so many cases with this condition in such a short period of time.”
Stern says the research was prompted by the surge in cases at UC Davis. “This is a condition that was previously rarely seen in our busy clinic,” he says. “What we would really like to do is spread awareness of this issue. We have seen a great number of affected animals. Given that this is a reversible form of this devastating disease, we really want to ensure that veterinarians can recognize the risk and treat it expediently when needed.”
Stern says choosing “a well-researched dog food that has a healthy nutrient profile backed by expert formulation and research is of paramount importance.”
The Culprit: “Boutique” Pet Foods
Pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients, are what’s being linked to DCM, which leads to reduced heart pumping function and increased heart size. The alterations in heart function and structure can result in severe consequences such as congestive heart failure or sudden cardiac death. While the most common cause of DCM is genetic, on rare occasions other factors can also result in the condition, particularly in breeds that are not frequently affected.
Stern says the disease is now showing up unexpectedly in other breeds, such as the golden retriever. The common link unifying these cases is their diets. He began noticing the trend two years ago — while treating many dogs with nutritionally mediated DCM he realized that they were all eating similar diets. Last year, the U.S. Food and Drug Administration issued an alert to pet owners and veterinarians about the potential association between the diets, which have become quite trendy, and DCM. The FDA continues to research this issue in an effort to help identify the exact dietary factor causing the problem.
Study Looked at Golden Retrievers
Stern’s research involved 24 golden retrievers with dilated cardiomyopathy and a documented taurine deficiency. Twenty-three of the 24 dogs diagnosed with DCM had also been fed diets that were either grain-free, legume-rich or a combination.
“The study was a clinical study looking at affected dogs and their response to therapy,” explains Stern. “The published study included 24 golden retrievers, which represents the largest collection of taurine-deficient DCM cases in the literature.”
Stern prescribed the dogs a diet change and added a taurine supplement to their diet. All but one dog showed improvement. Nine of 11 dogs in this group — including Suva pictured above — had the most advanced stage of the disease, congestive heart failure. These dogs also showed dramatic improvements or no longer had congestion, says Stern.
Recommendations to Give Clients
Stern said veterinarians should educate clients about their dogs’ diet. He also cautions that dogs can develop DCM from nutritional origins and not be taurine-deficient. Taurine supplements can also mask the problem and lead to a delay of an important diagnosis.
But when the problem is related to taurine deficiency, says Stern, it may not be that the diet is “grain-free” or “legume-heavy” but that ingredients are interacting to reduce availability of taurine or that other nutrients are missing or interacting in the formulation.
For example, while a lot of pet owners may not want to see “byproducts” in their dog’s food, often the byproducts contain organ meat like heart and kidney, which are good sources of taurine.
For more information on selecting foods for your pet, Stern recommends that clients consider using the recommendations set by the World Small Animal Veterinary Association for selecting a healthy dog food.
Stern says the UC Davis clinic continues to treat patients with DCM. “Since the study, we have collected many many more cases and we continue to diagnose and treat these patients today.”
Co-authors of the study include Andrea Fascetti and Jennifer Larsen, veterinary nutritionists with the UC Davis School of Veterinary Medicine, and Joanna Kaplan, a veterinary cardiology resident in the UC Davis Veterinary Medical Teaching Hospital.
Read: Heart Failure in Dogs.
Get practical tips from cardiologists on heart failure in dogs in this downloadable PDF.