The FDA recently reported a list of 16 brands of grain-free food that have been most frequently identified in 524 reported cases of DCM, which included 515 dogs and nine cats. Many people are feeding these foods and are now very concerned about what they should be doing to protect their pets from heart disease. What is behind all this?
In 2017, veterinary cardiologists from locations around North America noticed a sudden increase in the cases of dilated cardiomyopathy (DCM) that they were seeing, in breeds that don't typically develop DCM.
DCM is a form of heart disease where the walls of the heart become thinner and the heart can no longer pump blood effectively. Unfortunately, DCM doesn't necessarily cause a heart murmur that your veterinarian can hear. Clinical signs can include lethargy, weakness, weight loss, collapse, coughing, increased respiratory rate, labored breathing, and/or abdominal distention. There can be heart arrhythmias, such as atrial fibrillation or a very rapid heart rate that your veterinarian can hear. Sometimes the arrhythmias can cause sudden death without anyone realizing there was a problem.
Certain breeds of dog are at higher risk for DCM; in these breeds it is a genetic problem. Doberman Pinschers, Irish Wolfhounds, Boxers, Great Danes, and Cocker Spaniels develop DCM much more frequently than other breeds. A deficiency in carnitine, which plays a critical role in energy production, is implicated in Boxer DCM and supplementing Cockers who have DCM with taurine seems to help their heart disease.
But in 2017, there were 24 golden retrievers diagnosed with DCM that had a taurine deficiency. All 24 of these dogs were being fed one of nine different brands of dog food, eight of which were labeled as "grain-free." Researchers found a "statistically significant association" between a low taurine level in the dog and the brand of diet in 63% of the dogs. All but three varieties of food eaten by these DCM dogs were "legume-rich": beans, peas, and lentils. The other main ingredient in the foods eaten by 67% of the dogs were pork products.
The researchers also found that most of the affected dogs were eating fewer calories than would be expected and less than the amount recommended by the pet food manufacturer.
Another study evaluated 48 dogs (of various breeds) with DCM. Of these dogs, 36 were fed a grain-free diet (the rest were eating a diet that included grains) and 39% of the 36 were eating the same brand of food. In this study, none of the dogs showed a taurine deficiency. The 14 dogs eating the same brand of grain-free food had more severe heart disease than those dogs eating a food containing grains. Several of these dogs were treated with taurine and all were switched to a new diet, with an improvement in their heart function. The interesting part is that two of the dogs were switched from one grain-free food to a different grain-free food and their hearts improved. So just a lack of grains is probably not the cause of diet-associated DCM.
Does this mean that if you are feeding one of these brands you should immediately switch to a different diet? We don't know. The veterinary cardiologists are confident that there is a dietary factor that is causing heart disease in some dogs. But it is too much or too little of a nutrient? Is it a combination of specific ingredients? Is it due to the way the food is processed? Is it the quality or source of the ingredients? We don't know yet. Research is on-going and we all hope to have more information in the near future.
If you are feeding one of the named products, or probably a grain-free food containing legumes and/or pork in the first 5 ingredients, you may want to gradually (over a week or so) switch over to a different formula. I recommend sticking with brands that have a veterinary nutritionist and a prescription diet line: Royal Canin (what I feed my pets), Science Diet, Iams, or Purina.
For more information, please read my article in Madison Essentials: https://madisonessentials.com/Article/2019-01/Grain-Free
Check out the FDA site: https://www.fda.gov/animal-veterinary/news-events/fda-investigation-potential-link-between-certain-diets-and-canine-dilated-cardiomyopathy?fbclid=IwAR1WOK_zKUs16kf1Ks0A47gvTJlSn95H3vk1QIWclQqYwK-pxzOwPs0O4CA#diet
and talk to your veterinarian (not the sales person at the pet store, please!)
Information for this article was obtained from Veterinary Practice New, July 2019 and the FDA.gov website.