Certain pet diets can cause cause heart problems

Many years ago, veterinarians recognized deficiency of an amino acid called taurine as the most common cause of dilated cardiomyopathy in cats.  Cats are unable to make their own taurine (just like people can’t make their own vitamin C) and must ingest it to stay healthy.  

Taurine is plentiful in most animal tissues.  Being carnivores, domestic, feral and wild cats that hunt for their food derive adequate taurine from their diet.  In the past, many commercial cat foods didn’t have enough taurine for cats and caused dilated cardiomyopathy and other health issues. Once the issue came to light, pet food companies added more taurine to the foods they manufacture for feline deits. 

For cat being fed an appropriate diet, taurine-associated dilated cardiomyopathy in cats has all-but disappeared.  It is occasionally diagnosed when cat owners feed unbalanced diets (e.g., boiled poultry or vegetarian diets) or use dog food as a substitute.

An example above of a grain-free diet

More recently, certain breeds of dogs were found to also have dilated cardiomyopathy associated with taurine deficiency.  This was unexpected because dogs, unlike cats, are able to synthesize taurine from other sulfur-containing amino acids in their food.  Investigators suspected that these breeds were unable to synthesize taurine in amounts needed to replace losses. Taurine is typically efficiently recycled in the small intestine, but various dietary factors can affect this process. When supplemented with high doses of taurine, these dogs resolved their cardiomyopathy in many cases.

X-Ray of large globoid heart suggestive of dilated cardiomyopathy

Since then, certain types of diets have been implicated in heart disease. The food category associated with heart disease falls into the grain-free diets. It is unclear if the processing of taurine isn’t working with these diets or if there is an absorption issue. What we do know, is grain-free diets have been implicated in several hundreds of cases reported by veterinarians to the FDA in recent years.

Are all “limited ingredient” or “grain free” diets at fault?

Some dogs are prescribed diets to diagnose and treat allergies (skin or gastrointestinal diseases).  Such diets might include a limited number of uncommon ingredients, such as salmon, kangaroo, potatoes, peas, etc.  Many brands are creating these diets and they should be avoided. 

It is appropriate to note that limited ingredient diets manufactured by Hills, Purina and Royal Canin have  NOT been associated with current cases of diet-associated cardiomyopathy.

It is also important to realize that there is no medical or nutritional indication for “grain free” although some therapeutic diets recommended to diagnose and treat allergies may happen to be grain free,  these diets are usually chosen because the ingredients are new for a specific patient such as duck and peas. They are not being recommended because of being grain free. The marketing fad of grain free is simply that: a marketing strategy that mirrors what people perceive as healthier. In truth, there is no specific benefit.

What should I do if my dog eats a grain-free legume based or other implicated diet?

First, check the ingredient label an the manufacturer. If the food is made by Hills, Purina or Royal Canin, the food is likely appropriate and you can confirm with your family veterinarian. If peas or lentils are the main ingredient (or main carbohydrate source), consider changing to a diet with the same protein that  also contains grains.

Second, if you are reluctant to change the diet, consult your veterinarian about having a cardiac ultrasound (echocardiogram) to see if your dog has evidence of cardiomyopathy.  If your dog is found to be affected, even if it’s showing no clinical signs, the diet must be immediately changed and your pet requires taurine supplementation. Most nutritionists recommend using the WSAVA guidelines for selection of commercial diets.  

Taurine measurements can be helpful, however, these measurements only reflect what is in the blood, not how much taurine is in the muscle of the heart. For that reason, taurine measurements alone don’t always reflect the cardiac health of a patient.

If affected, your veterinarian or veterinary cardiologist is the one best able to advise you about the most appropriate course of action for your dog.

What about cats?

A few cat cases have been reported to the FDA, but the numbers are too small to say anything definitive. Currently, this appears to be primarily a dog problem.

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