Grain free and exotic protein food – What we know
The FDA has announced that they are looking into reports of dilated cardiomyopathy in dogs that have been fed pet foods containing peas, lentils, other legume seeds, or potatoes as main ingredients (these are commonly considered grain-free foods).
What is dilated cardiomyopathy (DCM)?
Dilated cardiomyopathy is when the heart muscle has weakened contractions and decreased ability to pump blood through the vascular system. As the disease progresses, the chambers of the heart become enlarged, the heart valves may begin to leak, and the dog can develop congestive heart failure.
What is taurine?
Taurine is an amino acid. Historically, dogs fed diets containing appropriate levels of protein are able to make enough taurine to meet their needs and do not need it supplemented in their diet. At this time it is not completely understood why some dogs on grain-free and exotic protein foods are taurine deficient. It could be due to the diet lacking the precursors (methionine and cysteine) dogs need to synthesize taurine; decreased bioavailability of methionine, cysteine, or taurine; increased urine loss of taurine, altered metabolism of taurine due to interactions of ingredients with each other and the normal flora within the GI tract; or due to genetic variation between breeds. Further research is needed to answer these questions.
Why do we care about taurine deficiency?
Dogs with taurine deficiency often develop dilated cardiomyopathy.
What we know…
There has been a suspicious number of cases of DCM across numerous dog breeds in dogs consuming BEG diets (boutique, exotic protein, grain-free). These diets do not contain grain, instead they contain legumes, lentils, peas, fava beans, or potatoes as a main ingredient (main ingredients would be one of the first five ingredients listed on the dog food bag). Exotic proteins are proteins that have not been traditionally used in pet food such as kangaroo, venison, bison, duck, and salmon.
At this time there is no cause and effect proof that these types of diets are causing DCM. Additional studies and research need to be performed to evaluate these suspicions. However, there is enough evidence available at this time that should be acknowledged and raise concern.
A study involving Golden Retrievers found dogs with DCM and taurine deficiency had been fed grain free foods. After confirming DCM and taurine deficiency the dogs’ diets were changed. 17 of the 21 dogs switched to a grain inclusive diet and the other 4 dogs switched to different grain free diets. All 21 dogs were also given a taurine supplement. Of the 21 dogs only one had a persistently low taurine level following diet change and supplementation; it had remained on a grain-free diet. The remaining 20 dogs had significant clinical improvement; several were able to discontinue heart medication. This study does not prove grain-free diets are causing DCM, but it demonstrates that more research is needed.
Another study looked at 48 dogs with DCM and known diet histories, these dogs did not have taurine deficiency. This study included several different dog breeds that were eating either grain-free or grain-based diets. Various heart measurements were recorded. Some of the measurements showed more severe heart disease in dogs on grain-free diets compared to grain-based diets; however, other heart values demonstrated no difference between the groups. Again this does not prove grain-free food is causing DCM; it just demonstrates the need for more research.
Common Myths about grain based dog food
Myth: Grains are a common allergen
First, what is a food allergy? A food allergy is when a dog’s immune system does not recognize a protein as food but instead sees it as an invader and mounts an immune response against it. Most often this causes skin issues and/or gastrointestinal issues in dogs (Food allergies are not the only thing that cause these types of issues in dogs).
The incidence of food allergies in dogs and cats is actually quite low, environmental allergies are more common. Dogs can be allergic to nearly any protein or carbohydrate ingredient in a diet; however, most dogs are allergic to the animal proteins and not the grains.
Several studies have been performed that have evaluated what ingredient most dogs are allergic to. One study concluded that the most common allergens listed in order from most common to least common were beef, cow’s milk, lamb, chicken, chicken eggs, wheat, soy, and corn. Another study found the most common food allergens for dogs were beef, dairy products, chicken, and wheat.
It is important to understand that advertising can be misleading, and that there is no available diet that is completely hypoallergenic. Most often when a dog is put on a diet trial they are given food with limited ingredients, proteins they have likely not been exposed to, or hydrolyzed protein (which are proteins that have been broken down to smaller components to “hide” from the immune system).
Myth: Dogs are carnivores, they shouldn’t eat grains
As dogs became domesticated they changed genetically as well. In fact, when comparing them to carnivorous wolves, domesticated dogs have genes that play key roles in starch digestion and fat metabolism.
Myth: Corn and grains are just fillers and have no nutritional value
Corn and grains are included in dog food because they contribute energy and other essential nutrients. These ingredients also can add fiber to the diet which is important for gastrointestinal health. It is important to recognize that grain-free diets still contain about 40-60% starch, it just comes from a different source. In the end there is no nutritional difference.
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