In July 2018, the US FDA announced it was investigating a link between grain-free dog foods and a serious heart condition known as Canine Dilated Cardiomyopathy (DCM). In DCM, the heart becomes enlarged. Symptoms include fatigue, difficulty breathing, coughing and fainting. Canine Dilated Cardiomyopathy can result in sudden heart failure.
According to the FDA press release, "The U.S. Food and Drug Administration’s Center for Veterinary Medicine and the Veterinary Laboratory Investigation and Response Network a collaboration of government and veterinary diagnostic laboratories, are investigating the potential association between reports of canine dilated cardiomyopathy (DCM) in dogs and certain pet foods the animals consumed, containing peas, lentils, other legume seeds or potatoes as main ingredients. Canine DCM is a disease of a dog’s heart muscle and often results in congestive heart failure. In cases that are not linked to genetics, heart function may improve with appropriate veterinary treatment and dietary modification if caught early."