During recent years there has been an increase in the incidence of diet associated cardiac disease. It is proposed that this is due to the increase in popularity of grain free dog food, however it is important to note that this association is under investigation and as yet, no link has been proven. Ongoing studies aim to discover more about the relationship between grain free diets (GFD) and cardiac disease.
Dilated cardiomyopathy (DCM) is a disease that affects the heart muscle, weakening it, so reducing the ability of the heart to pump blood. The heart chambers dilate, and the muscular walls become thin. Symptoms of DCM include lethargy, weakness, coughing, weight loss, exercise intolerance and abdominal distension.
Traditionally DCM was seen in mainly large breed dogs and the disease had a strong genetic component. However, in the past few years there has been an increase in the cases of diet associated DCM and this has coincided with the increased popularity of GFD. Not all GFDs cause diet related DCM and not all dogs with DCM eat GFD. DCM is one of the most common heart diseases in dogs, so a dog with DCM that is fed a GFD may not necessarily have developed the condition from the food.
Most of the food in reported cases of diet associated DCM contain high levels of pulses such as peas and lentils, in the absence of grains, these are the chief carbohydrate source. Pulses have been included in dog food for decades but not in such high proportions until the GFD became popular.
Diagnosis is made with an ultrasound of the heart which will clearly show the thin heart walls and lack of contractility. Unfortunately, there is no specific test to show the diet is what caused the heart disease. Learning about a dog’s dietary history is crucial to diagnosis as diet related cases of DCM respond very well if the diet is changed and the condition caught early. Left untreated it will lead to a progressive fatal heart disease.
There is no single best food and certainly most dogs do very well on a balanced commercial diet. Until more is known about the link between DCM and GFD, it is a good idea to avoid diets containing high levels of pulses. More work needs to be done in researching the potential benefits or otherwise of GFD, there is no scientific evidence suggesting grains are not healthy for dogs. Grain allergies do exist but are rare.
In conclusion, there are gaps in scientific and veterinary knowledge meaning the link between GFD and DCM cannot be ascertained without further research.