The subject of gluten in food has been a hot topic issue for a while. Many people have sworn off gluten due to its actual or perceived effects on health. Now pet owners are beginning to wonder about the effects of gluten on their pets, leading to the question “should my dog be eating gluten or not?” Some pet food brands offer grain-free options, whilst some dog owners will even prepare a special diet for their dogs, home-cooked to perfection.
But how much does your dog benefit from a gluten-free diet? Is the gluten-free diet a fad, or is there some truth to the matter?
What is Gluten?
Gluten is a protein that is found in grains such as wheat, rye, barley, and triticale. Gluten is what helps dough to stick together when flour and water are mixed. Gluten also gives dough an elastic quality, helps it to rise as it bakes, and gives bread a satisfying chewy texture.
Why is Gluten a Problem?
For most people, gluten causes no problems. Unfortunately, some people are sensitive to gluten, or have health conditions that make them react badly to gluten-containing foods. People who react badly to gluten in their food often feel more comfortable and healthy if they reduce or even eliminate gluten from their diet.
Why is there Gluten in Dog food?
Some might argue that wolves and other wild canines would never eat wheat-based products, so why should we be feeding gluten to our pet dogs. The truth is the matter is more complicated than this.
Like humans, dogs can suffer from allergies or food sensitivity. The foods most likely to provoke allergies in dogs are beef, dairy, wheat, chicken, and eggs: surprisingly natural ingredients! It’s also important to realise that dogs and wolves are genetically different. Dogs have been living alongside humans for thousands of years, and in that time, they have evolved the ability to digest starch (a key component of grains and many plants).
So many dogs can happily eat grains and vegetables as part of their diet without ill-effect. Indeed, many gluten-free or high-end brands of dog food contain grains such as rice or corn, or include fruit and vegetables in their ingredients. According to one study (Beynen AC, 2020) there are no reports of hypersensitivity to corn, rice, barley, rye or oats; however, wheat allergies have been reported.
Gluten Free versus Grain Free
The terms Gluten-free and Grain-free are often used interchangeably, but this isn’t accurate. Grain-free food contains no grain, and will provide the carbohydrates the dog needs through a vegetable source such as pumpkin or potatoes. Some vegetables are higher in carbohydrates than grains; for example, potatoes. Other types of seeds, such as chia, may be included, but there isn’t much research on their effects on dogs at the moment.
Gluten-free food does not contain gluten. That means no rye, triticale, barley or wheat. Gluten-free dog food may still contain other grains, such as corn or oats.
When is Gluten a problem for dogs?
As 2020 noted, some dogs are allergic or sensitive to wheat. True wheat allergies are not that common: about 1 dog in 10,000 will have a wheat allergy. The general term for gluten sensitivity in dogs is Gluten-Sensitive Enteropathy. Other terms include Celiac disease, Gliadin-sensitive enteropathy of Irish setters, Gluten intolerance, and Wheat-sensitive enteropathy.
A dog with Gluten-Sensitive Enteropathy will have a bad reaction when they eat gluten-containing food. The most common symptoms are weight loss and diarrhoea. Of course, a dog doesn’t need to be purebred to have gluten-sensitivity, but certain breeds are more likely to develop problems. This condition can be inherited in Irish Setters, though there isn’t any evidence that it is heritable in other breeds. In dogs with this condition, gluten has a toxic effect on the gut’s mucosal cells. The dog’s immune system reacts to gluten, causing inflammation in the gut.
Some dogs with food allergies may show skin issues when they eat gluten. Labrador Retrievers, West Highland White Terriers, and Cocker Spaniels are most likely to have food allergies. Affected dogs usually have itchy skin. The itching will not vary in intensity as the seasons change.
Border Terriers are predisposed to a condition called Paroxysmal gluten-sensitive dyskinesia. This condition affects the dog’s movement. Border Terriers affected by this disease remain fully alert but will have involuntary movements of one or more limbs, but also show gastrointestinal symptoms such as vomiting and diarrhoea.
How is Gluten-Sensitive Enteropathy diagnosed?
Dogs with Gluten-Sensitive Enteropathy usually develop symptoms at around six months old. You may notice weight loss, poor appetite, poor growth, and diarrhoea. Some dogs may also be gassy or prone to vomiting.
Your veterinarian can do several tests: blood tests are useful to rule out other conditions. In some cases your vet may need to take a biopsy from the dog’s intestine to confirm the diagnosis. An ultrasound exam may show that the intestines have thicker walls than normal. Your vet may also recommend a “gluten challenge”, which involves feeding the dog a gluten free diet for a period of time, then offering a gluten-containing diet; if the symptoms return after the gluten-containing diet, this strongly suggests Gluten-Sensitive Enteropathy.
How are Food Allergies causing skin issues diagnosed?
Apart from your dog’s history and symptoms, the most reliable way to confirm a food allergy is an elimination diet. Your vet will put your dog on a strict diet where your dog may only eat a particular food (usually hydrolysed dog food, specially prepared to not trigger allergies) for three months: no treats, no titbits, only this special food is allowed. If the itching resolves, the issue was probably dietary.
To confirm this, the dog should be given some of the normal diet to eat. If the skin symptoms return, the food allergy can be confirmed. It is also possible to continue the elimination diet to try to determine which individual ingredient is causing the problem.
What should I do if my dog has a problem with Gluten?
If your dog has a health condition that is affected by gluten in their diet, they will probably need to eat gluten-free food. You can speak to your veterinarian, who will be able to recommend a suitable diet. Your vet may also be able to consult a nutritionist if your dog’s issues are more complicated.
My dog is healthy: should I still avoid Gluten?
If your dog doesn’t have any dietary issues, you probably don’t need to worry too much about a gluten-free diet. If your dog seems happy eating a diet that contains gluten, and the food is generally of food quality, you don’t need to feel guilty. The most important thing is that your dog is eating food that is overall good quality and in the right amount. You can find more articles about the right diet for your dog here.
If you are ever concerned about your dog’s diet, speak to your veterinarian. Ignore the conspiracy theories: veterinarians are NOT paid massive amounts by pet food companies to recommend products!
Beynen, Anton. (2020). Beynen AC, 2020. Gluten proteins for dogs. 68-78.
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Orgain, V., 2020. Common Pet Food Myths and Trends. [online] VIN: 42nd Annual OAVT Conference & Trade Show. Available at:
< https://www.vin.com/members/cms/project/defaultadv1.aspx?id=9494443&pid=24858& > [Accessed 6 December 2021].
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< https://www.vin.com/members/cms/project/defaultadv1.aspx?pid=607&id=5110524 > [Accessed 6 December 2021].
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< https://www.msdvetmanual.com/dog-owners/skin-disorders-of-dogs/allergies-in-dogs > [Accessed 6 December 2021].