We have had a number of clients contact us about the reports in the media about the links between some grain-free diets and cardiomyopathy in dogs. Many of these people are questioning the dog food choices they make for their pets. We are learning more about this issue but still at this point there are a lot of important details that are not well understood. There are recent studies that have had conflicting results about the direct association between these diets and cardiomyopathy.
To clarify a little bit – cardiomyopathy is a progressive disease that leads to weakness of the heart muscle. In most cases there is a genetic link – several breeds of dogs – Doberman Pincher, Boxer, Cocker Spaniel, and Great Dane are the best examples of breeds with a genetic tendency to develop this condition. Recently over the last few years, cardiologist were noticing cases of cardiomyopathy in mixed breed dogs, or in dogs that were not considered “typical” breeds for cardiomyopathy. Many of these dogs were on grain free diets that were high in legume (peas). Some dogs on these diets that developed cardiomyopathy were tested and found to be low in the amino acid Taurine. Taurine is not considered an essential Amino Acid for dogs – a protein building block that must be included in the diet – because dogs are able to make their own Taurine as long as the diet contained other amino acids like Cysteine. Interestingly, Taurine is an essential amino acid for cats – they are not able to make their own so cat diets have been supplemented with Taurine – found in fish and organ meat since the 1970s. Prior to that, there were cats that developed Taurine nutritional deficiency and resulted in cardiomyopathy.
Researchers still don’t have an answer for why certain dogs eating a grain free diet developed taurine deficiency. Perhaps some dogs that eat a grain-free diet high in legumes have a problem producing enough Taurine – some enzyme pathway may be blocked. It does not appear to affect all or even most dogs. Many dogs have been on limited ingredient grain free diets, prescribed for various medical conditions for long periods of time and only a limited number have developed cardiomyopathy.
It would be an incorrect oversimplification to say that grain-free diets cause heart failure. Unfortunately – we have seen irresponsible statements like that from veterinarians and from media reports.
So in trying to decide what diet to feed your pet – if you are currently feeding a limited ingredient grain free diet that is high in Legumes, we first have to know if there is a medical reason (like food allergy, or inflammatory bowel disease) that led to that diet choice. Many cardiologist are advising that until we know more about this condition if the diet choice was not made for a medical reason – it may be safest to feed a diet that is not high in legumes – perhaps a diet with grains like oat, rice, or barley.
If the diet that is being fed is a grain free diet with legumes and the diet has helped resolve a food allergy or other dietary intolerance and owners do not want to change there are a few precautions that should be considered. We can evaluate for cardiomyopathy with a cardiac ultrasound. This is an important diagnostic test for any dog with coughing, panting, loss of stamina or weakness – particularly if on a grain free diet. We can also test for Taurine levels with a blood test. If dog’s that are on these diets are found to have cardiomyopathy and/ or low Taurine levels we can add a Taurine Supplement (and also likely change the diet). Nutritionist advise that a safe dose for Taurine supplementation for dogs is about 250 mg per day – it is available as a powder or tablet form in the vitamin section. Recently some dog food manufacturers are starting to add extra Taurine into some of the grain free diets.