On June 27, 2019, the U.S Food and Drug Administration (FDA) issued its third public report on a potential link between certain grain-free dog foods and dilated cardiomyopathy (DCM), a type of canine heart disease that affects the heart muscle.
Although the FDA clearly stated it was “continuing to investigate and gather more information in an effort to identify whether there is a specific dietary link to development of DCM” – click-bait headlines popped up almost immediately “warning against 16 different dog food brands” or that “grain-free dog food causes heart disease in dogs.” Not surprisingly, many pet owners were left confused and panicked by the onslaught of all of the information and misinformation.
So what is the truth and what should pet owners know? DCM (dilated cardiomyopathy) is a serious but rare condition. No pet owner wants to receive the devastating news that their dog has developed this heart disease. Common symptoms of DCM in dogs may include: loss of appetite, pale gums, increased heart rate, coughing, difficulty breathing, periods of weakness, and fainting. Of the 77 million dogs in the U.S., 0.5% to 1% have DCM, and of those dogs with DCM, less than 0.1% are speculated to have DCM related to diet, although that is not scientifically proven. While DCM tends to affect large and giant breeds, older or overweight dogs, veterinary cardiologists say they are also seeing an increase in cases in medium and smaller breeds that are not known to have a genetic predisposition to DCM.
The most recent FDA update on DCM included data it gathered from 2014 through 2019 related to 560 cases of DCM in dogs. According to the FDA brief, the FDA has “been investigating reports of canine dilated cardiomyopathy (DCM) in dogs eating certain pet foods, many labeled as ‘grain-free,’ which contained a high proportion of peas, lentils, other legume seeds (pulses), and/or potatoes in various forms (whole, flour, protein, etc.) as main ingredients (listed within the first 10 ingredients in the ingredient list, before vitamins and minerals). Many of these case reports included breeds of dogs not previously known to have a genetic predisposition to the disease.”
The FDA states that “based on the data collected and analyzed thus far, the agency believes that the potential association between diet and DCM in dogs is a complex scientific issue that may involve multiple factors.”
Further in the report, the FDA stipulates that, “the reports include dogs that have eaten grain-free and grain-containing foods and also include vegetarian or vegan formulations. They also include all forms of diets: kibble, canned, raw and home-cooked. Therefore, we do not think these cases can be explained simply by whether or not they contain grains, or by brand or manufacturer.”
So, to what degree has a link between dietary factors and canine DCM already been established through valid, peer-reviewed scientific evidence?
The FDA’s new investigation seems to be an attempt to further clarify this relationship. Is it the case that some dogs require more dietary taurine, cysteine, or methionine than the relevant nutritional guidelines currently provide? Are some pet food products failing to meet those guidelines in the first place (regulatory pre-clearance is not required, and studies have documented various nutritional deficiencies in the past)? Or could it be a question of bioavailability—are dogs actually able to absorb the amino acids found in certain products or ingredients?
Certainly, more research needs to be done into DCM and its causes. The FDA is using a range of science-based investigative tools as it strives to learn more about its potential link to certain diets or ingredients.
Finally, it’s important to realize that the FDA stated on July 12, 2018, February 19, 2019 and June 27, 2019 that the agency does not advise any dietary changes based solely on the information gathered. It is important for pet owners to understand these updates on DCM and make the best decisions for their pets.