Common grain-free dog food ingredients may fuel canine heart disease

A new study from Tufts University has found that some dog food ingredients may be driving heart disease in our canine companions, and these same ingredients are often included in grain-free dog food products. The study looks specifically at canine dilated cardiomyopathy (DCM), a disease that impacts the heart muscle.

To investigate the potential link between diet and DCM in dogs, the researchers looked at both traditional dog foods and the foods linked by the FDA with canine DCM. More than 800 compounds were evaluated, with the study finding that 88 biochemical compounds were higher in the dog food products associated with DCM by the FDA.

As well, the study found 23 compounds that are found in lower quantities in these DCM-linked dog foods. Additional work narrowed things down to the "top 30 compounds" that separate the two different dog food groups (DCM-linked and non-DCM-linked). Finally, the researchers say that four specific ingredients distinguish these two groups: chicken/turkey, rice, lentils, and peas.

Peas, in particular, had the greatest link to higher concentrations of the potentially problematic compounds in DCM-linked dog foods. Dog foods linked to DCM are, according to the study, more often than not marketed as 'grain-free' options, using ingredients like sweet potatoes and potatoes in place of more common ingredients like corn and rice.

The study goes on to explain:

When all four distinguishing ingredients are plotted, the ingredient-compound relationship for peas shows more solid bars for peas compared to the other ingredients, supporting the possibility that peas contribute to higher concentrations of these biochemical compounds. In contrast to peas, rice and chicken/turkey are associated primarily with open bars, indicating lower amounts of the compounds in association with these ingredients. Compared to peas, ingredient-compound associations for lentils are fewer, but in a similar direction as peas.

The researchers note that at this time, they can't say whether the presence of peas and, "to a lesser degree," lentils and the compounds they contain are the cause of DCM in dogs. However, they do note that dog foods containing these ingredients were also "commonly associated" with the compounds found in higher levels in DCM-linked diets compared to others.

"The findings support peas as a leading possible ingredient associated with diet-associated DCM in dogs," the study concludes. That doesn't mean these ingredients are inherently risky to dog health, however, with the study putting forth possible explanations about the links between these foods and DCM, including potential nutrient deficiencies in these food formulations.