This study* retrospectively reviewed medical records of dogs diagnosed with dilated cardiomyopathy (DCM) over a 40-month period at an academic institution. Records were included only if the food brand and variety were adequately documented and there was an echocardiographic diagnosis of DCM.
Dogs were grouped into grain-free (GF) or grain-based (GB) diet groups based on label ingredients as reported by the manufacturer. Diets were categorized as GB if wheat, rice, oats, cornmeal, barley, bulgur, millet, rye, and/or spelt were listed or as GF if none of these grain products were listed. The GF group was further subdivided into 2 categories: those eating the most commonly fed GF diet (GF-1; n = 14) and those eating one of 12 other GF diets (GF-o; n = 22). Additional information evaluated from the records included echocardiographic variables, presence or absence of concurrent congestive heart failure, results of ancillary testing (eg, whole blood or plasma taurine, plasma L-carnitine, blood selenium, infectious disease testing, necropsy [if available]), and information regarding diet change, if performed.
A total of 91 patients were included. There was a lower median weight for GF-1 dogs as compared with GB dogs. Dogs eating GF diets (both GF-1 and GF-o) had greater left ventricular diastolic measurements than dogs eating GB diets. Most dogs eating any GF diet received taurine supplementation (regardless of taurine level results) and a diet change; 7 GF-fed dogs (GF-1, 6; GF-o, 1) were later re-evaluated and were shown to have clinical and echocardiographic improvement. No GF-fed dogs experienced new-onset or recurrent heart failure after diet change.
The authors concluded that the study results provide compelling evidence that a nutritionally based, partially reversible cardiomyopathy occurs in some dogs fed GF diets from smaller brands and is likely associated with more than just an omission of grains.
