Over the past 5 years, the number of dog and cat food companies competing for market share in the United States has exploded. Many smaller pet food companies have entered the marketplace, often relying on novel approaches to pet nutrition to set them apart from the larger, well-established companies. These boutique pet food companies often tout high-quality ingredients, exotic protein sources, grain-free formulations and raw or unprocessed ingredients as reasons their foods are superior to other brands. Because they are small companies, many do not have their own manufacturing plants, and their diets are produced at large processing plants that may manufacture diets for several companies. Taken together, these boutique companies account for about 20% of dog food sales per year.
These factors, among others, contributed to a bumper crop of diet-related pet health concerns over the past several years. Pet food recalls have become a common news item in the media. Melamine contaminated ingredients sourced from China, excessive Vitamin D from “outsourced suppliers”, contamination problems with Salmonella, E coli, Listeria, and other pathogenic bacteria have resulted in recalls of numerous diets. So far in 2019, three pet food companies that produce traditional diets have had recalls, and six “raw food” diet brands have been recalled.
The latest pet food health alert involves clusters of cases of an uncommon heart condition, known as dilated cardiomyopathy or DCM, that have occurred in dogs that were being fed “grain-free” legume (peas or lentils) or potato containing diets. Veterinary cardiologists noticed an unexpected increase in the number of dilated cardiomyopathy cases in 2018 and soon found a link to these diets in the patients’ histories. Since then there has been 560 dog, and 14 cat cases of DCM, with a connection to these diets, reported to the FDA Center for Veterinary Medicine, which is investigating the issue. In DCM, the heart muscle is weakened, so that it cannot contract properly, which eventually results in the dilation of the heart and eventually heart failure. Decades ago veterinarians were seeing DCM cases erupt across many different breeds and in crossbred dogs as well. After a large research effort across several different veterinary medical disciplines, it was found that the majority of the cases of DCM were due to deficient levels of the amino acid taurine in the dog food diets. The results of the investigation led to changes in the nutritional requirements for adequate taurine levels in dog food diets to prevent further cases. After those changes were instated, the number of DCM cases dropped.
Veterinarians are again looking at a taurine connection in this current outbreak of DCM cases. They have found that 93% of the diets of affected dogs contained peas or lentils. In many cases, a low taurine blood level is documented, and in many cases, taurine supplementation and/or a diet change away from lentil-based “grain-free” diets results in improvement and in some cases resolution of the disease. The science of nutrition is complicated. A pet food company might be adding the required amount of taurine to their diets, but use a source that is not readily absorbed through the intestine or has a low bio-availability. It may be sometime before the exact nutritional mechanism behind DCM is known, but veterinarians love a challenge. Pet owners need to realize that DCM develops silently, until the signs of heart failure – exercise intolerance, a cough, fainting – become apparent. It can take years to develop. The diagnosis is made with an ultrasound exam of the heart, and it is treatable. There have been DCM cases in cats reported to the FDA as well, but far fewer than dog cases. So far, none of the diets associated with these cases have been recalled, they are still in the marketplace. You can go to Ashland Veterinary Hospital’s facebook page for links to the FDA and the UC Davis School of Veterinary Medicine investigations.
Dr. Tesluk is a graduate of the UC Davis School of Veterinary Medicine and practices at Ashland Veterinary Hospital