There is a good deal of confusion and controversy when it comes to the subject of corn and soy products being used in dog foods. There are those who claim that these products should never be used to feed dogs while many experts believe they are perfectly fine. In fact many prescription dog food like the Royal Canin Urinary So Small Dog Dry Food contain corn.
So, what’s the answer? Are corn and soy healthy for dogs or not? You may have to decide for yourself. First, learn the basic arguments for and against the use of these ingredients in commercial pet foods.
The Argument Against Soy and Corn in Dog Foods
According to folks who believe that soy and corn are a bad idea for dogs, the modern dog isn’t that far removed from their ancestors -- wolves and wild dogs who spent their time hunting in the forests and on the plains.
Because our canine pets still have the same basic digestive systems as their ancestors, the argument goes, the “natural,” and thus most healthy, diet for dogs is meat and internal organs (also called by-products). Meat and meat byproducts are what dogs have eaten over thousands and even millions of years and thus the dog’s body is well adapted to this diet. Grains and soy, on the other hand, which were not part of the original canine diet, cannot be properly processed by the dog’s digestive tract.
The people in this camp point to the fact that many dogs have allergic reactions to soy and corn as evidence of their claim. Dogs that are allergic to these products can develop a variety of skin problems.
Why are soy and corn part of so many dog foods? The nay voters say it’s simply because they are cheap sources of protein and energy. The dog food maker can utilize these protein sources cheaply, and people in this camp suggest that corn and soy are “fillers” that are largely useless to dogs as usable protein.
The Yea Vote
The other side, those who are fine with feeding dogs corn and soy admit that these products aren’t the best type of protein for your pet but that they do the job as an added source. Meat is the most balanced form of protein, but small amounts of soy or corn gluten in dog foods can help balance essential amino acids and, in general, are as digestible as meat based proteins.
In addition, soy and corn give your dog things that meat can’t: fiber and carbohydrates, which will satisfy a dog’s appetite with fewer calories and provide energy in a form that the body uses well. People with this view often point out that dogs are actually omnivores, eaters of both plants and animals, and thus can do quite well with a partially plant based diet. Our dog’s wolf-like ancestor frequently ate the contents of the digestive tract of their kills, which would have been full of carbohydrates and fiber.
Corn and soy can indeed cause allergies, but the percentage of dogs with allergies to them is small when compared to the number of dogs allergic to beef, dairy, or chicken. Soy and corn do not even make the top 10 list. As long as your dog has no problem in this department, the yea vote says corn and soy are fine.
As for the ancient ancestors argument, those who have no issue with corn and soy might also say that dogs have long lived off table scraps. Whatever humans eat is often what their canine companions eat. Since humans eat more corn and soy products than ever, dogs should have no problems adapting, as they’ve always done.
As in most things that have to do with your family pet, the decision comes down to you, the dog’s owner and caregiver.
Certainly your dog’s food should start with a high quality meat as their primary source of protein. Whether you buy foods that also use corn and soy should depend on your dog’s particular health needs, the views of your vet, your budget, and your own thoughts on the matter.
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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian. It has however been reviewed for accuracy by Dr. Joe, a board certified veterinary nutritionist and graduate of Cornell University's program for Veterinary Medicine.