GUELPH, ONTARIO — Canine dilated cardiomyopathy (DCM) has been a hot-button issue in the pet food space following an explosion of grain-free or pulse-inclusive formulations. Though these formulas sought to appease consumers who questioned the usage of carbohydrates and grains in pet nutrition, they soon became connected to DCM following an investigation from the US Food and Drug Administration (FDA).

In September 2020, the FDA claimed it could not establish a clear connection between DCM and grain-free pet food, leaving consumers and the industry with more questions than answers. New research from the University of Guelph is attempting to remedy this.

“This study is the longest, controlled feeding study to date to assess cardiometabolic health in healthy adult dogs fed pulse-inclusive diets,” said Kate Shoveller, Ph.D., a professor in the Department of Animal Biosciences in the Ontario Agricultural College, Champion Petfoods Chair in Canine and Feline Nutrition, Physiology and Metabolism, and lead author of the study.

Pulses can serve as a great protein source in pet food products and have been included in many plant-based dog food formulas. However, concerns have risen that these ingredients may not provide enough key amino acids for dogs to produce taurine and maintain their heart health. According to the newly released research, which appears in The Journal of Nutrition, lentils, beans and peas are safe and healthy for dogs.

Funded by Champion Petfoods, the study used 28 Siberian Huskies, which are not genetically at risk for DCM, for a randomized, controlled trial. For 20 weeks, each dog was fed a diet that either was formulated with 0%, 15%, 30% or 45% whole pulse ingredients, specifically green and yellow peas, pinto beans, chickpeas and lentils. All the diets included the same animal protein source, chicken, and were formulated with the same protein and fat levels.

According to Pawanpreet Singh, Ph.D. student in animal biosciences at the University of Guelph and lead author of the research, the pulse concentrations reflected current formulas in commercial dog foods.  

“We wanted to keep all aspects of the diets the same except the amount of pulse ingredients so that any changes we saw in the dogs’ cardiac function could be attributed to the differing amounts of pulses and not nutrient intake,” Singh said.

The study examined echocardiograms, performed by Dr. Shari Raheb, a professor at Ontario Veterinary College’s department of clinical studies, as well as routine bloods samples. Adronie Verbrugghe, Ph.D., DVM, clinical studies professor and Royal Canin Veterinary Diets Endowed Chair in Canine and Feline Clinical Nutrition at the OVC, performed body scans to assess each dog’s body composition at the beginning and end of the study.

“This research is important to help veterinarians make evidence-based diet recommendations for their patients,” Verbrugghe said. “Some dogs might be healthy, but others could have specific health conditions for which protein sources and content are targeted.”

The research found that dogs fed the pulse-inclusive diets showed no indications of heart issues. The dogs’ body compositions were also not affected, as they altered less than 0.1% from baseline no matter which diet they were fed.

“We took the highest precautions to monitor the health of these dogs,” Singh said. “We made sure to conduct monthly health checks and evaluate their heart blood markers to make sure there were no signs of cardiac stress. We found that regardless of the amount of pulses consumed, none of the dogs showed changes to indicate the development of DCM or body composition changes.”

According to Shoveller, previous clinical studies in DCM have failed to examine whether pulse ingredients play a role in the disease, specifically with dogs that are not genetically predisposed.

“Our data suggests the inclusion of pulse ingredients in dog food is not a causative factor and emphasizes the importance of understanding the nutrient composition of each ingredient and ensuring that foods exceed minimum nutrient requirements,” Shoveller said. “Ultimately, pulses are a dependable protein alternative in the food industry and this study emphasizes their safety even when incorporated at high concentrations.”

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