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essential nutrition advice for your pet.

Is a Grain or Gluten Free Diet Right For my Dog?

How to Know if Your Pet Needs Gluten or Grain Free Dog Food


By Lorie Huston, DVM


Choosing a diet for your dog is a task that should not be taken lightly. Grain free and gluten free pet diets have become extremely popular. This popularity has mirrored the appearance of similar products for people. These diets are particularly helpful for people that have celiac disease, intolerance to glutens in general, or allergies to wheat.


Many pet owners choose to mimic their own food choices when choosing a food for their pet. With the increase in the number of people choosing to consume a grain free or gluten free diet, pet food manufacturers have recognized that similar pet diets are attractive to pet owners. The popularity of these diets has led to an increase in the number of grain free and gluten free diets available for pets.


Are these diets the best choice for your dog? How do you know if your pet needs a grain free or gluten free dog food?


Grain Free Versus Gluten Free


Let’s start by discussing the difference between a grain free and a gluten free diet. Grain free dog foods are, as the name implies, diets that do not contain grain. Gluten free dog food, on the other hand, may or may not contain grain as an ingredient. Gluten is the protein that is found in specific types of grain, namely wheat, barley, and rye. Gluten free dog food is, of course, free of these proteins. However, not all grains contain gluten. Therefore, gluten free dog food may or may not be grain free, while grain free dog food will always be gluten free.


Does My Dog Need a Grain Free Diet?


Most dogs do not actually require a grain free or a gluten free diet. But how do you know if your dog does require one of these diets? To answer that question, let’s take a look at some of the common reasons pet owners choose to feed their dog a grain free or a gluten free diet.


Proponents of grain free diets claim that grains are an unnatural source of nutrition for our dogs. They argue that ancestors of our current-day dogs did not eat grains. While their ancestors may not have eaten grains, dogs have evolved to be able to digest grains and glutens pretty easily. Dogs possess several genes that have been modified through the course of their evolution to allow them to easily digest carbohydrates.1  That includes grains. So, while most dogs do very well eating a grain free diet, these diets are not required in terms of metabolization.


Another reason that many dog owners choose to feed grain free or gluten free dog foods is a mistaken belief that these diets are the best choice for dogs that have food allergies. While food allergies do occur in pets, corn and other grains are not among the most common allergens found in foods. In fact, according to some of the available research, corn is actually one of the least likely sources of food allergy. In one literature review, 278 dogs with food allergy were evaluated and the problem ingredient was clearly identified for each dog. Beef was the most common allergen, being responsible for 95 of the cases reported. Dairy was responsible for 55 cases, making it the second most frequent cause. Corn was identified as the offender in only 7 cases.2


For dogs that truly do have allergies to grains, a grain free diet would be an appropriate choice. The following are symptoms that would be expected in dogs that have food allergies (or other types of allergies):


  • Itchiness
  • Excessive hair loss
  • Bald patches
  • Inflamed skin
  • Sore and scabs
  • “Hot spots”


A food trial with a grain free food would be necessary to determine whether the food is beneficial for your dog.


Does My Dog Need a Gluten Free Diet?


Unlike in people, celiac disease is uncommon in dogs. As a result, most dogs do not require a gluten free diet. The exception to this is the Irish Setter. A small number of Irish Setters have been documented to suffer from a congenital disease that results in an intolerance to gluten. This has only been reported in certain Irish Setters and only in the Irish Setter in the U.K. These dogs, however, will benefit from a gluten free diet.


Image: Srdjan Fot / via Shutterstock




1. Axelsson, Erik et al. The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Nature. 2013; 495: 360–364

2. Carlotti DN, Remy I, Prost C. Food allergy in dogs and cats. A review and report of 43 cases. Vet Dermatol 1990;1:55-62.

Chesney CJ. Food sensitivity in the dog: a quantitative study. J Sm Anim Pract 2002;43:203-207.

Elwood CM, Rutgers HC, Batt RM. Gastroscopic food sensitivity testing in 17 dogs. J Sm Anim Pract 1994;35:199-203.

Harvey RG. Food allergy and dietary intolerance in dogs: a report of 25 cases. J Sm Anim Pract 1993;34:175-179.

Ishida R, Masuda K, Sakaguchi M, et al. Antigen-specific histamine release in dogs with food hypersensitivity. J Vet Med Sci 2003;65:435-438.

Ishida R, Masuda K, Kurata K, et al. Lymphocyte blastogenic responses to inciting food allergens in dogs with food hypersensitivity. J Vet Intern Med 2004;18:25-30.

Jeffers JG, Shanley KJ, Meyer EK. Diagnostic testing of dogs for food hypersensitivity. J Am Vet Med Assoc 1991;189:245-250.

Jeffers JG, Meyer EK, Sosis EJ. Responses of dogs with food allergies to single-ingredient dietary provocation. J Am Vet Med Assoc 1996;209:608-611.

Kunkle G, Horner S. Validity of skin testing for diagnosis of food allergy in dogs. J Am Vet Med Assoc 1992;200:677-680.

Mueller RS, Tsohalis J. Evaluation of serum allergen-specific IgE for the diagnosis of food adverse reactions in the dog. Vet Dermatol 1998;9:167-171.

Mueller RS, Friend S, Shipstone MA, et al. Diagnosis of canine claw disease – a prospective study of 24 dogs. Vet Dermatol 2000;11:133-141.

Nichols PR, Morris DO, Beale KM. A retrospective study of canine and feline cutaneous vasculitis. Vet Dermatol 2001;12:255-264.

Paterson S. Food hypersensitivity in 20 dogs with skin and gastrointestinal signs. J Sm Anim Pract 1995;36:529-534.

Tapp T, Griffin C, Rosenkrantz W, et al. Comparison of a commercial limited-antigen diet versus home-prepared diets in the diagnosis of canine adverse food

reactions. Vet Therapeutics 2002;3:244-251.

Walton GS. Skin responses in the dog and cat to ingested allergens. Vet Rec 1967;81:709-713


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Comments  4

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  • This is pure BS
    01/23/2015 02:37am

    Let's not kid ourselves here: if you can afford a high quality food with no yuck in it, GET IT. This includes preservatives, colors, "flavors", gluten, soy, and especially corn. If you are on extremely low income, get purina, by all means. I would never (I happen to not despise my furry companions). Purina is probably the worst offender of all.

    Anything that is bad for you, like everything above, my rule of thumb is to not feed it to my innocent pet. (Although, even though grains are terrible for human beings, I eat them anyway. You don't have to practice what you preach, just don't feed your dog what is, essentially, poison).

    Don't believe this bs, because that's exactly what it is. Don't get me wrong, I'm not one of those people who think dog nutrition is exactly the same as human nutrition. However, who in good conscience could give their poor canine something like corn? Monsters, that's who. Gluten is one of the least offenders- it's no corn or soy or artificial chemicals, but it's also not fresh meat, veggies, and fruits.

  • 11/10/2016 01:20am

    And where did you get your Animal Nutrition Degree? Internet doesn't count--you can find any garbage on the internet to support whatever misinformation you wish to believe. Note the 16 tiny paragraphs that follow the article. Those are called scientific references, where actual professional research is performed. Ever notice that corn is yellow? Why is that? Well, a nutritionist will let you know it is the antioxidants, such as lutein, which are present in large amounts in this native American grain. Do you know what an AAFCO statement is and where to find it? Well, I guess you are experimenting on your dog, after all.

  • One other reason for GF
    03/21/2015 04:48pm

    I was told by my vet that many grains cause inflammation and can aggravate arthritis in dogs and that GF dog food is healthier in that regard and also would benefit the dog's coat. Of course, there is poor quality GF dog food out there, so you need to do your research to be sure you are buying one that has been rated good quality. I would hope there is info out there on quality GF dog food that is done by researchers not associated with any dog food companies. If you do choose a dog food with grain, it should be listed farther down in the ingredient list and not toward the top, but it is best to avoid it especially if you know your dog has arthritis. That is what I was told.

  • 06/24/2015 05:38am

    Spring16 I was told the same thing, and there's plenty of information all over the net about how grains cause inflammation. Would you believe the arthritis foundation in Australia however doesn't support this, stating there's no real evidence arthritis symptoms are worsened when eating grains (they say the same about nightshade vegetables like white potatoes and eggplant all those with arthritis say you should avoid). So I was very confused after talking to them having avoided grains for both my dogs with arthritis. Of course the foundation says you can test it by eating grains then stopping etc, but my dogs' arthritis is not so bad it stops them from walking etc so I can't really tell if grains has made it worse or not, and what I worry about is the 'invisible' pain of inflammation that doesn't necessarily prevent movement but is still felt. I hope the author of this article or someone else can provide advice on this confusing and controversial topic!

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