Grain-Free Diets & Canine Cardiac Disease: An Epidemiological Examination with Big Data

Presentation Description / Summary: Grain-free diets and their potential association with dilated cardiomyopathy (DCM) and other cardiac diseases in dogs have generated significant attention within the veterinary community. This session summarizes the findings from four upcoming studies that collectively advance our understanding of this complex topic. First, we present a systematic review of the grain-free diet and cardiomyopathy literature, evaluating study design, statistical power, data validity, and overall quality of evidence using GRADE criteria. Our findings highlight that existing evidence is preliminary, underscoring the need for further research. Next, we use Dog Aging Project data from over 44,000 dogs to assess the validity of owner-reported grain-free feeding and its relationship to cardiac outcomes. Misclassification of diet status is common, but simulations demonstrate that any resulting bias would likely attenuate observed associations. In longitudinal analyses, no relationship was found between grain-free diets and cardiac diagnoses over 2.5 years of follow-up. Building on this, a second longitudinal study of over 50,000 dogs followed for four years similarly found no association between any diet type (kibble, canned, home-prepared, raw, or fresh) and cardiac disease. Finally, a case-control study focusing on dogs diagnosed with DCM found no significant associations with diet type; ingredient-level analyses are ongoing and will be ready by 2026. Together, these findings represent one of the most comprehensive evaluations to date and provide clinicians with an updated, evidence-based understanding of the current state of knowledge, while highlighting key gaps present in the field and priorities for future research.