Concerns about grain-free foods began back in 2018, when the Food and Drug Administration (FDA) released a statement concerning grain-free diets and dilated cardiomyopathy (DCM) in dogs. DCM is a heart condition that results in a decreased ability to pump blood effectively. 

The FDA’s initial statement told the public that there was an increasing number of reports of DCM in dogs and that this was possibly linked to grain-free dog foods. Grain-free dog foods contain ingredients like potatoes and pulses, in place of grains (rice, wheat, oats). Pulses are dry-harvested legumes, including beans, peas, chickpeas, and lentils. Since their initial statement, the FDA did release an update a few years later to let the public know that DCM is a multifactorial issue with plenty of variables. 

Throughout this period, the scientific community investigated grain-free diets and DCM in dogs and many have published research regarding this topic. Published research articles have established the safety and digestibility of grain-free diets for dogs. These studies have suggested that grain-free diets do not affect taurine status negatively. Results from these studies showed no association between grain-free diets and DCM. 1-4

More recently, a long term study was published investigating high animal protein and low animal protein grain-free and grain-inclusive diets over a 6 month period. The purpose of this study was to understand how pulses impact canine digestibility as well as DCM. Four different diets were created, two grain-free (pulse and potato containing) with low or high amounts of animal protein and two grain-inclusive with no pulses or potatoes and containing low or high amounts of animal protein. Macronutrient digestibility of each diet was investigated by looking at the dog’s fecal characteristics, fecal metabolites and fecal microbiota. 

All four of the diets were well digested by the dogs, and all dogs remained healthy throughout the study. The grain free diets resulted in shifts in the fecal microbiota with increases in short chain fatty acid concentrations (SCFAs). SCFAs are known to be beneficial for gut health. Essentially, this study revealed that none of the formulas had negative impacts on digestibility in dogs. The researchers concluded that whilst some have thought that pulse-rich diets could be a cause of nutrition-associated DCM in dogs due to negative effects on digestibility, the current study showed all diets (including pulse-rich diets) were highly digestible. 5

Check out our earlier blog posts about DCM and grain-free diets!

References

1. Donadelli, R. A., Pezzali, J. G., Oba, P. M., Swanson, K. S., Coon, C., Varney, J., … Shoveller, A. K. (2020). A commercial grain-free diet does not decrease plasma amino acids and taurine status but increases bile acid excretion when fed to Labrador Retrievers. Translational Animal Science, 4(3). https://doi.org/10.1093/tas/txaa141

2. McCauley, S. R., Clark, S. D., Quest, B. W., Streeter, R. M., & Oxford, E. M. (2020). Review of canine dilated cardiomyopathy in the wake of diet-associated concerns. Journal of Animal Science, 98(6), 1–20. https://doi.org/10.1093/jas/skaa155

3. Pezzali, J. G., Acuff, H. L., Henry, W., Alexander, C., Swanson, K. S., & Aldrich, C. G. (2020). Effects of different carbohydrate sources on taurine status in healthy Beagle dogs. Journal of Animal Science, 98(2), 1–9. https://doi.org/10.1093/jas/skaa010

4. Pezzali, J. G., & Aldrich, C. G. (2019). Effect of ancient grains and grain-free carbohydrate sources on extrusion parameters and nutrient utilization by dogs. Journal of Animal Science, 97(9), 3758–3767. https://doi.org/10.1093/jas/skz237

5. Clark, S. D., Hsu, C., McCauley, S. R., de Godoy, M. R. C., He, F., Streeter, R. M., … Quest, B. W. (2023). The impact of protein source and grain inclusion on digestibility, fecal metabolites, and fecal microbiome in adult canines. Journal of Animal Science, 101(August), 1–18. https://doi.org/10.1093/jas/skad268