DCM on the rise in small breeds

Veterinarians around the world have seen a sharp rise in cases of dilated cardiomyopathy (DCM, in which the heart is enlarged and weakened) in dogs not previously recognized as predisposed to this condition. The one linking factor: a grain-free diet based on exotic ingredients.

“For the past year we have begun to notice a trend of DCM in dogs that do not typically develop DCM,” says Dr. Ryan Fries, a board certified cardiologist at the University of Illinois Veterinary Teaching Hospital in Urbana.

Dilated cardiomyopathy is most commonly seen in large breed dogs, including Doberman Pinchers, Irish wolfhounds, and Great Danes. But recent cases have included dogs such as Boston terriers, Yorkshire terriers, and Pomeranians.

Uncommon Diets Appeared as Connection

“We started looking for infections and other contributing factors, and these dogs’ diets appeared as a connection. We noticed it because the diets were so uncommon and included unusual sources of protein not frequently used in dog food,” says Dr. Fries.

As concern mounted, multiple institutions, including the University of Illinois and the Food and Drug Administration, have begun attempting to identify a reason that these particular diets would cause a cardiac issue.

“Despite a lot of testing, we have yet to identify a specific deficiency of an essential vitamin, mineral, or amino acid. There has also been no specific cardiac toxin identified. So we do not know exactly what is causing the negative cardiac effects yet,” says Dr. Fries.

One factor that appears to play a role in the problem is the size and experience of the pet food manufacturer.

“These boutique diets tend to come from smaller manufacturers that may not have the nutritional expertise and resources to ensure quality control that the larger, established companies have,” says Dr. Fries. “We are not yet seeing DCM in smaller dogs fed grain-free diets produced by large-scale manufacturers.”

There have also been multiple cases of dogs fed home-cooked diets that developed DCM.

DCM Reversal Possible with Early Intervention

In the 1980s, a similar rise in DCM developed in cats. That problem was eventually linked to commercial pet foods being deficient in taurine, an amino acid found in animal protein. So veterinarians and researchers initially thought the current cases of DCM in dogs might be due to a taurine deficiency. Low taurine levels have been documented in some dogs; however, nutritional analyses of the suspect diets and many other dogs have shown adequate levels.

“There is potential for some unknown component or lack thereof that could be affecting the dogs’ ability to absorb and use the taurine. Research is exploring those options,” says Dr. Fries.

Changing the dog’s diet and supplementing taurine has led to a reversal of the DCM in some instances. Unfortunately, the improvements may take six to twelve months to occur.

“In many of the cases, the dogs are already in heart failure by the time DCM is diagnosed. They simply do not survive long enough to respond to the therapeutic diet change,” explains Dr. Fries.

Recommendations for Pet Owners

Although much research remains regarding this phenomenon of diet-related DCM, Dr. Fries says current knowledge supports specific recommendations for pet owners.

“While we haven’t yet established the mechanism, we have established the link between diets like these boutique, exotic ingredient, grain-free foods and dilated cardiomyopathy. If you are feeding your dog one of these diets, talk to your veterinarian about switching to another diet and scheduling your dog for a heart evaluation.”

Owners should look for dog foods manufactured by large, established companies backed by scientific research, quality control, and FDA approval. These diets have years of data to back their safety and ability to meet a dog’s nutritional needs.

“Diet is an important part of any pet’s health. Make sure to bring up your pet’s diet with your veterinarian, who can help you find a safe and nutritionally appropriate food,” says Dr. Fries.

If you have any questions about boutique, exotic ingredient, grain-free foods and their link to dilated cardiomyopathy, talk to your local veterinarian.

By Hannah Beers