In the past few years, many different brands of dog food have been marketing grain-free food to pet owners. There seem to be multiple reasons that grains have been cut from some dog diets, but the biggest reason I have been able to find is the idea that grains may not be necessary for dogs, as their wild counterparts (wolves, coyotes, other canids) are primarily carnivorous in nature. Another concern among pet owners is that grains may be linked to some allergies in dogs. However, within the last few months, there have been reports showing a possible correlation between Dilated Cardiomyopathy (DCM) and grain-free diets. I am personally very interested in this research as I will admit that my dogs have been on a grain-free diet. I am going to go over some of what has been shared and some of the current hypotheses that help explain this correlation.
Earlier this year, UC Davis School of Veterinary Medicine reported that they had been seeing an increasing number of Golden Retrievers being diagnosed with DCM. In some breeds, such as Doberman Pinschers, DCM is believed to be caused by a genetic component, but this was not known to occur in Golden Retrievers. Instead, the researchers discovered that some of the dogs afflicted with DCM were also taurine deficient. Taurine is an amino acid that dogs partially obtain from their diet and partially create on their own. The researchers also found that many of these affected dogs were eating grain-free diets. You can read more from UC Davis here and here.
On July 12, 2018, the US FDA released a statement “…alerting pet owners and veterinary professionals about reports of canine dilated cardiomyopathy (DCM) in dogs eating certain pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients.” You can read the FDA’s full report here. They did say that there were multiple breeds of dogs included in the report, and that several of them were recovering after receiving taurine supplements. They also urge pet owners and veterinarians to report any suspected cases of diet-related DCM.
Dr. Lisa Freeman, a veterinary nutritionist at Tufts University and collaborating with the researchers at UC Davis, has some ideas about what is really going on with dog diets. One of Dr. Freeman’s hypotheses is that the bioavailability of taurine in grain-free diets is less than in grain-inclusive diets. This could be due to the different ingredients used in grain-free diets, such as rice bran, peas, or lentils. Many grain-free or “boutique” diets also use different sources of protein like duck, bison, kangaroo, etc. There may be differences in how dogs are able to metabolize taurine based on their primary protein source. You can read Dr. Freeman’s full analysis here.
It seems we are just in the beginning stages of understanding the link between diet and heart disease in dogs. Interestingly, diet-induced DCM is a well-known issue in cats, and according to Dr. Freeman, most commercial cat diets supplement extra taurine. I am very anxious to see future studies on this topic because pet nutrition is important to me, both as a responsible pet owner and as a future veterinarian.