Have you ever noticed that some food just doesn’t agree with your dog? Food intolerance is quite a common issue in dogs, in which they struggle to digest certain ingredients. Unlike a true food allergy which involves the immune system, intolerances involve the digestive system, leading to symptoms like an upset stomach, as well as itchy skin. In this article, I’ll cover the symptoms of food intolerance, common triggers and how vets diagnose it. We’ll also explore the best dietary options for dogs with intolerances and sensitivities.
Key takeaways
- Food allergies, intolerances and sensitivities are slightly different, as allergies are more rare. However, all can cause digestive problems and skin issues.
- Proteins like beef, dairy, wheat, soya and egg are the most common causes of allergic reactions. Dogs can also be sensitive to or intolerant of a variety of other triggers including lactose, grains or just food that’s too high in fat.
- An elimination diet (carried out under the supervision of your vet) is the best way to identify food intolerances, giving your dog a very simple diet and gradually reintroducing other ingredients.
- Long term, you can help improve your dog’s digestive health by sticking to a consistent diet, avoiding known triggers and opting for a food that contains ingredients that support gut health, like prebiotics.
- Your vet will be able to help advise you if you notice any symptoms that could suggest your dog has a food intolerance. It’s especially important to go in for an appointment if you notice any persistent or worsening symptoms.
Table of contents
What is food intolerance in dogs?
Food intolerances vs sensitivities vs allergies in dogs
Signs and symptoms of food intolerance in dogs
Common causes of food intolerance in dogs
How food intolerance in dogs is diagnosed
The best dog food for food sensitivities
Managing food sensitivity in dogs long term
When to speak to your vet
What is food intolerance in dogs?
If your dog has a food intolerance, this means that their digestive system struggles to process certain ingredients. This might sound like an allergic reaction but there are some key differences – for one, allergies involve the immune system, leading to more serious reactions. Intolerances are also more common than allergies. [1]
Food intolerances, like allergies, can develop over time. So even if your dog hasn’t ever had problems with their usual food before, it doesn’t mean that it can’t be the trigger of an upset stomach. Dogs are more likely to develop a food intolerance to ingredients they eat more often.
Food intolerances vs sensitivities vs allergies in dogs
- Food allergies involve an immune system response. This is the most serious type of issue, and also the least common. It’s usually proteins that cause an allergic reaction to food. In severe allergies, even trace amounts of the ingredient can cause a reaction – this is why we advise that you should always speak to your vet when deciding what food’s best for your dog if they have allergies.
- Food intolerances cause a chemical reaction in the digestive system, which means you might see symptoms like an upset stomach, bloating and vomiting. Like an allergy, it’s usually caused by specific ingredients, but is not limited to proteins.
- Food sensitivities is often used as an umbrella term, but as well as referring to allergies and intolerances to specific ingredients, it could also be related to broader nutritional details. For instance, some dogs are sensitive to foods with high levels of fat, or to certain types of fibre.
| Food allergy | Food intolerance | |
| Specific ingredients | ✓ | ✓ |
| Can be triggered by trace amounts | ✓ | ✕ |
| Can develop over time | ✓ | ✓ |
| Symptoms | Immune system response, which may affect skin or digestive system. In severe cases, it can cause breathing difficulties. | Usually affects digestive system with symptoms such as bloating and vomiting. May also affect skin. |
Signs and symptoms of food intolerance in dogs
Let’s break down the most common symptoms of food sensitivity, intolerance or allergies in dogs. These symptoms roughly fall into two categories: digestive symptoms and symptoms that mostly affect the skin. If you notice any of these symptoms in your dog, it could mean there’s something in their food that doesn’t agree with them – although they can also be a sign of other conditions, as skin symptoms are more likely to be a result of environmental allergies to things, like pollen or dust mites.
Digestive symptoms
- Diarrhoea
- Gas
- Vomiting
- Soft stools
Skin and behavioural symptoms
- Itchy skin
- Ear infections
- Licking paws
- Restlessness
Common causes of food intolerance in dogs
There are some ingredients that are more likely than others to cause a reaction.
Common protein triggers
Proteins are the most common allergens, though even if your dog isn’t allergic to a protein, they might still have an intolerance. And some proteins are more likely to cause a reaction than others. That’s why in our hypoallergenic blends, we avoid beef, dairy, wheat, soya and egg – some of the proteins that dogs are most likely to have a reaction to. If there are any other ingredients you’d like us to leave out, just let our expert nutrition team know.
Other possible intolerance triggers
As well as having a true allergy to wheat, dogs might also be intolerant to gluten (which is found in wheat as well as other grains) or to grains themselves. We can make grain-free dog food to cater to dogs with these dietary needs, but it’s less common than people might think. Just like us, dogs can also be lactose intolerant – in fact, it’s quite common for dogs to be unable to digest milk or other dairy products. While many dogs love a bit of cheese as a treat (not too often, as it’s pretty high in fat) it can trigger digestive symptoms like an upset stomach. [2]
Can dogs develop food intolerance suddenly?
Dogs can develop a food intolerance at any time – even to foods they previously had no problem eating and enjoying. There are a few different reasons why this might be. An intolerance can develop over time as a result of repeated exposure to a particular ingredient, or changes in your dog’s gut microbiome. The breakdown of various types of healthy bacteria that live in the gut can affect how well dogs (as well as people) digest different things.
How food intolerance in dogs is diagnosed
The best way to find out whether your dog’s symptoms are being caused by food intolerance (and identify the ingredient that’s upsetting their stomach) is to carry out a food trial under the supervision of a vet. This involves following a special diet for a set period of time, which means identifying your dog’s food intolerance can take a little while – but stick with it, because your dog will feel much healthier and happier when they’re on the right food.
Elimination diets
An elimination diet is the only truly reliable way to find out what ingredients might be affecting your dog. When carried out under a vet’s supervision, it can be a real game changer when it comes to improving your dog’s health day-to-day.
The first step is cutting back the different foods you give your dog, down to just one type of hypoallergenic food (free of common allergens). Give them this diet for 6-8 weeks while monitoring their health. You should find that on this super gentle diet, any digestive issues disappear – if they don’t, that’s a sign that your dog’s health issues may not be related to food allergies or intolerances.
Gradually introduce more ingredients to see how your dog reacts. If you go slowly, you should be able to pinpoint the ingredients to avoid in future.
Dog food sensitivity tests
There are blood tests that can check for allergies, but not food intolerances. PDSA has also advised that blood tests aren’t reliable enough to make important decisions about your dog’s health and diet based on the results. [3] Another kind of test involves sending off a sample of your dog’s hair or saliva to check for allergies, but this technology hasn’t been proven to produce reliable results either. [4] Commercial gut microbiome tests are also available, and may be able to suggest possible dietary sensitivities, but they also need further study.
Here at Tails.com, we’d always recommend speaking to your vet as the first port of call if you think your dog might have allergies, sensitivities or intolerances. False positives or false negatives from commercially available tests could lead to you either avoiding ingredients unnecessarily or giving your dog something that doesn’t agree with them.
The best dog food for food sensitivities
Once you know the ingredients to avoid (or the type of food itself, like if it’s too high in fat or other macronutrients) you and your vet can work together to implement a long-term dietary plan for your pup’s health. Once that’s been worked out, you should be able to cut down the number of upset stomachs and other reactions a great deal.
Limited ingredient diets
A diet with fewer ingredients reduces the number of different things your dog’s being exposed to. If they’re sensitive to a number of different ingredients, this type of diet can help a lot.
Novel protein diets
It may also help to change to a dog food that uses different proteins than your dog is used to. This is because allergies and intolerances can develop over time, especially when it comes to ingredients that your dog eats often. As proteins are the cause of allergies, swapping them out can be a big help. Proteins that are less commonly used in dog food and are less known for causing allergic reactions include duck, venison and fish. We use proteins like lamb and salmon in our hypoallergenic food.
Sensitivity control dog food
Sometimes, people choose to give their dogs what’s known as “veterinary diets” which are designed especially for dogs with very particular dietary needs, which are often due to a medical condition. For instance, dogs with IBD are often given food that combines novel protein ingredients with low fat and low fibre, because this type of diet can help manage their condition. [5]
Hydrolysed diets
Another type of diet that can help dogs with allergies, sensitivities and intolerances (especially allergies) is a hydrolysed protein diet. Hydrolysis is a process that breaks down protein into such small pieces that they don’t trigger an immune response. This type of food is often used in elimination diet trials because it’s so unlikely to cause a reaction, but some dogs stay on a hydrolysed diet day-to-day.
Managing food sensitivity in dogs long term
Here are my tips as a nutritionist on how to look after your dog’s digestive health long term, managing their dietary sensitivities. If you’ve just found out that your dog is sensitive to certain ingredients (maybe even quite a lot of ingredients), don’t worry – most dogs can lead totally normal, comfortable lives once their condition is managed.
- Consistency: Don’t switch up your dog’s diet suddenly, especially if you’ve found food that doesn’t trigger reactions. Dietary changes that happen too fast can cause an upset stomach and might undo the good work you’ve done putting them on a diet that works for them.
- Avoid trigger ingredients: Work out what it is your dog can’t eat – that’s at the heart of managing their food sensitivities.
- Read labels carefully: As well as looking out for ingredients that will cause a reaction, look out for ingredients that can help support a healthy gut. Many dogs really benefit from prebiotics, which we can add to our sensitive stomach blends as well as our hypoallergenic dog food. Ingredients like beet pulp and FOS (Fructo-oligosaccharides) help your dog grow healthy bacteria to help them digest different ingredients. We also sometimes use chicory root which is a good source of inulin, another type of fibre.
Monitor your dog’s digestive health: Of course, it’s always important to keep a close eye on how your dog is doing. But if you think your dog might have food intolerances or sensitivities, it might help to keep a bit more of a detailed record. Make a note of symptoms like gas, stool quality or itchy skin.
When to speak to your vet
If your dog’s symptoms are persisting or getting worse, it’s all the more important to make an appointment with your vet to get their advice. This is especially true if you notice any of the following symptoms:
- Persistent diarrhoea
- Weight loss
- Lethargy
- Severe skin irritation
Your vet will be able to provide or work towards a diagnosis and a treatment plan for your dog, either ruling out serious health conditions or mapping out a path forwards. Food intolerances are more common than true allergies, as well as being a much more likely diagnosis than serious illness, so a trip to the vet’s should help set your mind at ease.
Conclusion
Food sensitivities or intolerances can have a big impact on dogs’ wellbeing, but once any trigger ingredients are identified, these issues are really manageable. Working together with your vet and keeping a close eye on any digestive issues will help you find a diet that works for your dog and keeps them happy and healthy.
Disclaimer: While we can create blends that avoid or exclude certain ingredients, we use a wide range of ingredients here at Tails.com. This means that there’s a very small chance that there might be traces of these ingredients in your blend. If your dog has severe allergies, please talk to your vet about how to feed them safely.
FAQs:
What are the symptoms of food intolerance in dogs?
Symptoms of food intolerance can vary but might include digestive issues like gas or an upset stomach, as well as skin reactions like itchy skin. Their behaviour might also seem different, because they’re not feeling well – if they seem stressed or restless, it could be down to a reaction to their diet.
What is the most common food intolerance in dogs?
The most common allergies are proteins, including beef, dairy, wheat, soya and egg. But as well as true allergies, dogs can also have sensitivities or intolerances to a range of other ingredients or types of food. For instance, lactose intolerance is common, and dogs might also be sensitive to macronutrients, such as fat or some types of fibre – food that’s too high in certain macronutrients could cause a reaction.
How do I know if my dog has a food intolerance?
Your dog might have a food intolerance if they show certain digestive, skin and/or behavioural symptoms. The most common symptoms to look out for are digestive issues like vomiting, diarrhoea or an upset stomach and skin issues like itching, which might cause them to lick themselves a lot.
Can dogs suddenly become intolerant to their food?
Yes, food intolerances can develop over time, meaning that food that has never affected your dog before might seem to suddenly cause a reaction. This can happen at any time during a dog’s life, so if you notice new digestive problems, don’t rule out food sensitivities.
Sources
[1] ‘Food allergies and intolerances in dogs’, Pet MD, 12 September 2024
[2] ‘Can dogs eat cheese?: FAQ’, Blue Cross
[3] ‘Food allergies in dogs’, PDSA
[4] ‘Hair and saliva test fails to identify allergies in dogs’, Journal of Small Animal Practice, 29 October 2018
[5] ‘Inflammatory bowel disease (IBD)’, The Cornell Richard P. Riney Canine Health Center