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Should you feed your pet grain-free foods?

by Dr. Noelle Weeks, Veterinarian, Veterinary Resource Center

There are a lot of dog and cat foods sold as grain-free with marketing suggesting that feeding no grains is healthier.  This is not true and can, in fact, cause illness for some dogs and cats.  There is no medical or physiologic basis to feed dogs or cats a grain-free diet. 

If a dog or cat has a specific food allergy there may be some medical reason to limit the carbohydrate source which can be done for some animals by feeding a grain-free food.  The grain-free fad started as a result of an anti-corn concern.  There was a concern that some dogs with food allergies would react to corn in dog food so that was removed as the carbohydrate source.  The carbohydrate source was replaced by tubers (potatoes and sweet potatoes) and legumes (peas and lentils); these foods were labeled ‘grain-free’.   The anti-corn sentiment has no basis in fact and is actually a myth.  Grains found in pet food can be corn, soy, wheat, rice, barley or other grains.  While some dogs or cats can develop food allergies to these sources the majority of pets can handle eating grains with no problem.  After all, many cats and dogs will eat grass; grass is a grain.  The grain-free foods will contain peas, lentils, other legume seeds, or potatoes as the carbohydrate source.

In 2017, veterinarians were seeing a certain type of heart disease, dilated cardiomyopathy, in dog breeds that aren’t prone to that type of heart disease.  Dilated cardiomyopathy is a heart disease where the heart dilates.  When the heart muscle dilates it becomes a very ineffective pump so that blood doesn’t circulate through the body well.  This disease, called DCM, can be fatal by causing heart failure.

There are certain breeds of dog who are genetically susceptible to developing DCM.  However, starting in 2017, DCM was being diagnosed in dogs with no known genetic susceptibility AND eating grain-free foods.  The veterinary field recognized that some dogs eating grain-free food developed heart disease from dilated cardiomyopathy.  There have even been some reports of cats developing DCM while being fed grain-free food.  In 2019, the FDA published a report about dogs diagnosed with DCM who ate a grain-free food.  Research has shown that some of the DCM in pets was due to taurine deficiency from the grain-free food but other pets developed dilated cardiomyopathy due to other reasons, which may include protein or thiamin deficiency, toxins or heavy metals in the food.

If you are interested in learning more about the link between grain-free food and dilated cardiomyopathy, please visit: