Food Allergy vs Food Intolerance: Spot the Difference

Digestive tract issues and unwelcome responses to foods affect people from a young age and can extend throughout our lives.

Digestive system discomfort can be from a many number of things. Most popularly discussed are IBS and celiac disease, but abdominal pain can sometimes be from food intolerance or food allergies. 

How do you know if you have food intolerance, food sensitivities or food allergies? Let’s look at the differences between the symptoms as a first step to understanding the causes of common food intolerances. 

Food Intolerance Symptoms

Unwanted reactions to food are categorized into either food intolerances or food allergies. Since symptoms are sometimes similar, food intolerances are mistaken for food allergies and vice versa. 

The main difference between food intolerances and food allergies is an immune response. Unlike food allergies, food intolerances do not involve an immune response to proteins in food. 

Food intolerances are much more common than allergic reactions to food and include symptoms of:

  • Heartburn
  • Nausea
  • stomach pain
  • Headaches
  • Nervousness or irritability
  • Bowel movement changes (diarrhea)
  • Gas, flatulence or bloating


The cause of food intolerances depends on the specific food causing symptoms of food sensitivity. For example, lactose intolerance can be a response from the absence of lactase in your body or a sensitivity to the fat commonly found in cow’s milk. Although uncomfortable, lactose intolerance can be managed by an elimination diet. It can also be managed by limiting your dairy intake as an effective food intolerance treatment. 

Intolerances or sensitivities can affect people or develop at any age. The symptoms are typically delayed reactions and can develop up to 72 hours after exposure. Many food intolerances resolve on their own and can be mitigated by avoiding or mitigating certain foods altogether.

Food Allergy Symptoms

Food allergies can range from mild to severe and often begin at an early age, most of the time in infancy. Approximately 1 in 10 children have a food allergy when compared to approximately 1 in 12 for adults.

In general food allergies to dairy, eggs and peanuts are more common in children than adults. Many children outgrow dairy and egg allergies but peanut and tree nut allergies are usually lifelong. 

Food allergies differ from intolerances because they have an immune response to the proteins in foods. Following ingestion of a certain food, antibodies react quickly and cause symptoms almost immediately and only up to two hours after. 

The only immune response that can have a delayed reaction of hours or days after ingestion is in individuals who have celiac disease. Celiac disease is an allergy that occurs in the small intestine to gluten found in wheat, barley and rye. Many individuals experience symptoms of gluten intolerance, but in order to diagnose an allergy to gluten a blood test is required. 

The 10 most common food allergies:

  • Peanuts
  • Soy
  • Eggs
  • Dairy (mostly children)
  • Wheat (celiac disease)
  • Eggs
  • Fish
  • Shellfish (mostly adults)
  • Tree nuts (almonds, walnuts, brazil nuts, pecans)


Some of the most obvious symptoms of a food allergy vs food intolerance include skin rashes, wheezing and immediate swelling. These symptoms are never present in cases of food intolerances.

Common symptoms of immune responses to food:

  • Tingling or itching in the mouth
  • Hives, itching or eczema
  • Swelling of the lips, face, tongue and throat or other parts of the body
  • Wheezing, nasal congestion or trouble breathing
  • Abdominal pain, diarrhea, nausea or vomiting
  • Dizziness, lightheadedness or fainting


In some individuals, a severe food allergy can occur known as anaphylaxis. This can be life threatening and should seek immediate medical treatment. Symptoms include closing of the airways, rapid pulse, loss of consciousness, shock and very low blood pressure.

How to manage symptoms of food allergies and food intolerances

Changes to your diet through food elimination can help identify food allergies and sensitivities. A popular diet known as the 4-food or 6-food elimination diet removes the most common triggers for allergies and sensitivities. 

Sensitivities to food are self reported and cannot be identified by a blood test the same way it can be for some allergies. The most common way to pinpoint intolerances is through an elimination diet process. 

Elimination diet includes:

  • Soy
  • Wheat
  • Eggs
  • Shellfish
  • Peanuts
  • Tree nuts
  • Fish


After the foods are removed for 4-6 weeks they are reintroduced to an altered immune system and microbiome. If there is no reaction when reintroduced they should remain in the individual's diet. 

Elimination diets are not recommended as a long term solution, unless there is a confirmed debilitating allergy. Removal of certain foods from diets long term can cause other problems such as deficiencies and malnutrition. 

Individuals with irritable bowel syndrome or IBS often report higher instances of food intolerances and food allergies than those without IBS. Options for people with IBS include the FODMAP diet. This has been known to improve abdominal pain, flatulence and bloating.

Manage Symptoms Naturally 

When dealing with food allergies sometimes reactions might be stronger than others. Natural allergy remedies can help manage symptoms of wheezing, sneezing, itchy skin and eyes. Helping to manage immune responses in a gentle way can help eliminate discomfort or intensity of symptoms. 

Avoiding anti-inflammatory foods can help manage inflammation that occurs throughout the body in response to foods. Inflammation is your body’s way of showing an immune response. Inflammation can present as joint pain, heat, redness and loss of function in an area of the body.

Inflammatory foods include sugar, processed foods, trans fats, refined carbohydrates, MSG, and omega-6 rich foods among others. Try swapping out inflammatory foods for products rich in fibre, health fats, green leafy vegetables, fruits and lean proteins. 

Another way to support the digestive tract is by supporting the growth of healthy bacteria in the gut. A healthy balance of gut flora helps the body’s metabolism, enhances the immune defense and helps protect against harmful pathogens and bacteria. 

Prebiotic fibre is naturally available from many foods including garlic, leeks, asparagus and chicory root. Prebiotic supplements are also available to help improve gut flora, especially when your diet lacks prebiotic fibre.