Grain-free dog foods and heart disease may have a connection, but the cause of the reported dilated cardiomyopathy cases in over 500 dogs is still unknown. Dog owners should be aware of the investigation and have a discussion with their veterinarian if they have been feeding a grain-free food or are concerned their dog may have dilated cardiomyopathy.
What is Being Investigated?
The Food and Drug Administration (FDA) has been investigating 515 reports of dilated cardiomyopathy in dogs since January 2014, 219 of those reports happening since December, 2018. More than 20 percent of these dogs overall (119) have died. Prior to this large number of reports, only one to three reports of dilated cardiomyopathy were received by the FDA each year. The recent influx in reports has led to an investigation to determine what the cause of this serious heart disease might be.
What Foods Are Possibly Involved?
91 percent of the reported cases involved grain-free foods, 93 percent of the dog foods that were reported contained peas and/or lentils in their ingredient lists, and 42 percent contained potatoes or sweet potatoes. Sixteen brands have been identified in multiple cases and the great majority were in a dry kibble form. Five brands, in particular, (Acana, Zignature, Taste of the Wild, 4Health, and Earthborn Holistic) account for 44 percent of the cases.
A Few Grain-Free Dog Foods Possibly Linked to Dilated Cardiomyopathy
- Acana (67 cases)
- Zignature (64 cases)
- Taste of the Wild (53 cases)
- 4Health (32 cases)
- Earthborn Holistic (32 cases)
- Blue Buffalo (31 cases)
- Nature's Domain (29 cases)
- Fromm (24 cases)
- Merrick (16 cases)
- California Natural (15 cases)
- Natural Balance (15 cases)
- Orijen (12 cases)
- Nature's Variety (11 cases)
- Nutrisource (10 cases)
- Nutro (10 cases)
- Rachael Ray Nutrish (10 cases)
Other dog food brands were also involved in the reported cases but had less than 10 cases associated with them.
What is Dilated Cardiomyopathy?
There are many different types of heart disease, but dilated cardiomyopathy is the specific heart disease that is being investigated. Dilated cardiomyopathy (DCM) occurs when heart muscle becomes thin and unable to pump blood as well as it should. Over time this causes the heart to become enlarged or dilated, and congestive heart failure can occur as a result. DCM is serious and can eventually cause death.
What is Causing This Dilated Cardiomyopathy?
Taurine (an amino acid) absorption and its synthesis from methionine and cysteine along with its excretion are being looked at as potential causes but other dietary factors are also being assessed. The amounts of protein, fat, moisture, crude fiber, total dietary fiber, soluble fiber, insoluble fiber, total starch, and resistant starch are also being looked at.
Necropsies of deceased dogs from these cases are also being reviewed along with a multitude of laboratory testing for surviving dogs and questions for pet owners. It is unknown whether or not there is a causative link to the grain-free diets identified in this investigation or if it is coincidental. Genetics and environmental factors may play a role as well, but the investigation is ongoing.
Since so many of the foods that were reported contained peas, lentils, potatoes and/or sweet potatoes, it is being speculated that one or more of these ingredients may be of concern. This is still only a speculation, since nothing has been confirmed.
Signs of Dilated Cardiomyopathy in Dogs
Early on in the course of this disease, there may not be any obvious symptoms to a dog owner. As dilated cardiomyopathy progresses and the heart muscle continues to weaken, a decrease in energy may be first noted. A veterinarian may hear a very subtle heart murmur as the heart valves begin to leak if the dog is brought in to the animal hospital.
What Should Concerned Dog Owners Do?
If a dog owner is feeding a grain-free food or is noticing any worrisome symptoms in their dog, they should discuss their concerns with their veterinarian. A dietary change to a food containing grains may be recommended, taurine levels may be measured, and an echocardiogram may be performed to assess heart function after the veterinarian performs a full physical on the dog. If DCM is diagnosed after these tests are performed, a report should be filed with the FDA and medications and/or supplements may be recommended based on the findings to manage the disease.
What Dog Food Brands Are Safe?
No one knows what is causing these reports of DCM in dogs, but since the majority of them involve grain-free foods, many veterinarians are recommending switching to grain-containing diets.
Historically, dog diets have been formulated to meet the nutritional requirements of dogs. As marketing trends in humans shifted towards grain-free options, the pet food industry followed suit with new companies offering an expansive selection of grain-free dog foods. Many of these companies do not have veterinary nutritionists developing their foods, so there is concern for nutritional safety, such as what may be discovered during this DCM investigation. Until this investigation is complete, it is recommended that a dog be fed a food that has been developed by veterinary nutritionists, is made by a company with a long history of producing quality diets, and meets the standards set by the Association of American Feed Control Officials (AAFCO). Hill's, Purina, and Royal Canin are three such companies that employ veterinary nutritionists that aid in developing and researching their dog food brands.