Grain-Free Diets

By: Carol S. Hillhouse, DVM, DABVP

TVMA Member
Panhandle, TX

Published December 2017

Grain-free diets for dogs are all the rage right now. Consequently, many dog foods market themselves by claiming to be grain-free while implying that grain is harmful, an assumption that is largely false. Mostly, it is a marketing ploy at the expense of what we know scientifically to be best for our pets. Grain-free food recommendations from celebrities, pet store employees and even pet food manufacturers often are based on misunderstandings of nutritional and digestive physiology.

No Scientific Evidence Supports Grain-Free as Superior Diet

There is a lack of scientific evidence that grain-free diets for dogs are nutritionally superior to those containing grain. Pet owners commonly regard carbohydrates and grain ingredients as fillers despite their nutritional composition. Grains like barley, wheat, corn and oats contain nutrients such as carbohydrates, fatty acids and proteins. In making a grain-free diet, pet food manufacturers simply substitute alternative carbohydrate sources like sweet potatoes, beans, peas or tapioca. These ingredients often provide fewer nutrients and less fiber, and they cost more. Decades of research prove dogs and cats digest grains well and utilize nutrients from them.

Grain-Free Diets Appropriate in Some Cases

Grain-free diets for dogs may be appropriate in certain situations. These diets are less likely to contain grain mites or storage mites, a skin allergen in some dogs that can produce an uncomfortable itch. Dogs that are sensitive to mites may be itchier after consuming foods that contain them. Fortunately, proper storage of food bags appears to limit this problem. Also, grain-free diets tend to be higher in omega-3 fatty acids, which have been shown to decrease inflammation. That is why some pets with allergic dermatitis tend to improve with grain-free diets even though they are allergic to pollens and not food.

Some people believe grains cause or worsen allergic disease. The term “grain-free” is not to be confused with “hypoallergenic,” because they mean entirely different things. Certainly, if pets have the genetic tendency or a medical condition that predisposes them to develop food allergies, they can become allergic. However, corn and other grain sources of protein cause far fewer allergic responses than animal-source proteins. A recent review of seven studies indicated that in more than 80 percent of adverse food reactions an animal product was responsible, not a grain. A truly food-allergic dog is diagnosed as such with a specific hypoallergenic diet and not necessarily a grain-free diet. These diets are not available as over-the-counter foods.

Dog Food Marketing Tailored to Pet Owners

Pet food is designed to appeal to humans, and we are emotional buyers. Look no further than a pet food aisle, and you will see descriptions such as “Party Mix,” “Chicken Feast,” “Hidden Goodness” and “Delicious Dry Dinner of Tender Meaty Pieces and Crunchy Bites with Potato and Green Bean Garnishes.” Dogs are less discerning as they are happy to eat feces, vomit, rodents and roadkill! Unless you have one of the rare pets that has displayed a sensitivity to grains, a grain-free diet is neither necessary nor superior. The biggest concern about a diet should be the nutrient profile and digestibility rather than the specific ingredients that it does or does not contain. Rely on your veterinarian instead of a marketing gimmick to pick an appropriate diet for your dog.

Dr. Carol Hillhouse owns two mixed animal practices in the Texas Panhandle: Carson County Veterinary Clinic and High Plains Animal Hospital.