Washington (AFP) - Recent years have seen a surge in grain-free dog and cat foods, as increasing numbers of pet owners cast aside kibble packed with cheap corn, wheat and barley fillers for what they believe is a healthier alternative.
The reality may be more complex, with the US Food and Drug Administration (FDA) announcing it was continuing to investigate a potential link between grain-free diets that have a high legume content and dilated cardiomyopathy (DCM), a canine and feline heart disease that can be fatal.
Thursday's announcement named 16 pet food brands most frequently identified in 560 cases of individual dogs reported to have the disease between January 1 2014 and April 30, 2018, with 119 of them dying.
Among these cases, more than 90 percent were fed products that were "grain-free" and 93 percent of the reported products contained peas or lentils as a main ingredient.
"We know it can be devastating to suddenly learn that your previously healthy pet has a potentially life-threatening disease like DCM," Steven Solomon, director of the FDA's Center for Veterinary Medicine said in a statement.
"That's why the FDA is committed to continuing our collaborative scientific investigation into the possible link between DCM and certain pet foods."
The investigation began last year and isn't yet complete, but the FDA said it had a "responsibility to shed light on a signal that we have been made aware of and to solicit reports from pet owners and vets that may know of related cases."
DCM is a serious disease of the heart muscle that causes the organ to dilate, making it harder to pump blood and causing the valves to leak.
This can cause a build-up of fluid in the chest and abdomen known as congestive heart failure, which can lead to death. It can be reversed if caught early with proper treatment and diet modification.
While DCM is not considered rare, the FDA investigation was sparked by a spike in cases among smaller breeds not genetically prone to the disease.
It is not fully clear what it is about these diets that may be connected to DCM.
It may be at least partly linked to a deficiency of an amino acid called taurine, and some dogs improved with medical care, diet change and taurine supplement, but others responded to diet change and vet care alone.
The FDA did not recommend switching from grain-free foods but advised pet owners to consult their vet for diet advice specific to their animal.
The brands named in the release were Acana, Zignature, Taste of the Wild, 4Health, Earthborn Holistic, Blue Buffalo, Nature's Domain, Fromm, Merrick, California Natural, Natural Balance, Orijen, Nature's Variety, NutriSource, Nutro, and Rachael Ray Nutrish.