Food Allergy vs Food Intolerance: What’s the Difference?

Everything you need to know about the differences, symptoms, examples, and ingredient swaps for food allergies and intolerances

Written by Liana Greenshields, Student in the Dietetics Specialization program at the University of Alberta and reviewed by our Health Stand Nutrition Dietitian Team. 

Food allergies and food intolerances can be difficult to understand and differentiate. They both cause the body to have an adverse reaction to a certain food, however, the reactions differ in symptoms, causes, and severity. In this post, we will explain what the differences are between a food allergy and a food intolerance, including some ingredient swaps for common allergens! 

What is the difference between a food allergy and an intolerance? 

The most significant difference is that a food allergy involves the immune system, while a food intolerance typically involves the digestive system. This means that the reactions to each are different in both symptoms and severity. Let’s break it down: 

Food allergies, as mentioned, are an autoimmune reaction where the body is tricked into thinking a certain food is a danger to the body. They are typically triggered by a protein such as milk, peanuts, or soy. This causes a reaction where the immune system triggers cells to release an antibody called immunoglobulin E (IgE) which neutralizes the allergen in the body. A food allergy reaction can range from mild to severe, and in some cases life-threatening. This type of allergy is known as anaphylaxis, which requires immediate medical attention. 

Food intolerances are caused by an adverse reaction in the digestive tract when the food cannot be properly digested. They are less severe than allergies and typically result in feelings of abdominal discomfort. 

Given these differences, it is clear that they can be difficult to distinguish and easy to misinterpret. Because of this, it is important to see a healthcare provider to obtain a proper diagnosis. 

Symptoms of allergies and intolerances 

One of the most common confusions amongst allergies and intolerances is the symptoms. Food allergy symptoms include: 

• Throat and mouth-tingling 
• Skin hives 
• Shortness of breath 
• Throat tightness 
• Wheezing  
• Pale/blue skin 

It is very important to never ignore the early symptoms of an allergic reaction! Allergies can be life-threatening and require immediate attention. 

As mentioned previously, intolerances involve the digestive system, resulting in the following food intolerance symptoms: 

• Stomach pain 
• Gas and bloating 
• Headache  
• Nausea and diarrhea 
• Heartburn  

Unlike allergies, food intolerances do not require immediate medical attention. Although still uncomfortable given the symptoms above, they will pass in time. Avoidance of the food is the best way to avoid experiencing any of the food intolerance symptoms above. 

The most common allergies and intolerances 

As mentioned above, food allergy reactions are typically triggered by a protein. The most common are as follows: 

• Cow’s milk 
• Tree nuts 
• Eggs 
• Peanuts 
• Shellfish 
• Wheat 
• Fish 
• Soy 

Unlike food allergies, intolerances are not primarily triggered by a protein. Some of these words may be unfamiliar to you, which can be another confusion surrounding food intolerances. The most common foods are listed below, with their specific component responsible for the intolerance in brackets: 

• Grains (gluten) 
• Dairy (lactose) 
• Nuts and seeds (salicylates and amines) 
• Pineapples, bananas, and avocados (histamines) 
• Dried fruits, wine, pickled foods, tea, beer (sulfites) 
• Fruits and vegetables (fructose) 

In the case of intolerances, the body typically cannot effectively break down or absorb the food. This inability is what causes the symptoms of discomfort. 

Testing and treatment 

Food allergy testing: 

For allergies, a skin prick test is the most common test used by allergists to diagnose an allergy. In this test, the allergist will place drops of the allergen on the patient’s skin, and then prick the skin so that the body absorbs it. After 20 minutes, the skin is checked for any redness or swelling; these are indicators of an allergy. A blood test can also be used to determine the immune system’s response to releasing immunoglobulin E (IgE) in response to foods. 

Unfortunately, there are no treatments for allergies. However, some individuals outgrow their allergies as they age, or see a decline in the severity of their reactions. When an allergic reaction occurs, an EpiPen should be used as this injects epinephrine into the body, helping to improve breathing, raise blood pressure, and reduce swelling in the throat and face. 

Food intolerance testing: 

Although there are many food intolerance tests available, they are not entirely reliable. The best way to diagnose a food intolerance is to simply take note of any of the food intolerance symptoms that are experienced following the consumption of a certain food; particularly one of the foods listed previously. 

Easy ingredient swaps for common allergens! 

Milk: 

• Soy milk provides almost as much protein, calcium, and vitamin D as cow’s milk and is, therefore, an excellent alternative (assuming you are not also allergic to soy milk as it can be common to be allergic to both). Nut milks may also be used, although they are lower in protein and fat.  
• Margarine or coconut oil can be used as a butter substitute. 
• There are many dairy-free cheese brands in grocery stores for a cheesy, dairy-free dish! 

Eggs: 

• Eggs provide structure to baked goods. To make an egg-free dish, use applesauce, a mashed banana, or ground flax seeds mixed with water. 

Peanut butter: 

• Any nut butter can be used as an alternative! For example, there is almond butter, pistachio butter, and cashew butter.  
• For nut-free alternatives, tahini and sunflower seed butter are great substitutes! 
• If you have an anaphylactic reaction to peanuts be sure you read labels and select products that are not produced in a facility that also contains peanuts. 

Wheat: 

• Many gluten-free grains are made into gluten-free flours. These include rice, potato, tapioca, corn, and quinoa. 

Whether you have a food allergy or intolerance, it can be difficult to know how to manage it. It is even harder to distinguish the difference between the two if you are unsure of what the differences are. If you experience any adverse reactions to a certain food group, this post may have helped you distinguish the differences between the two, along with common symptoms and ingredient swaps. A key takeaway is, however, that you can easily live with an allergy or intolerance due to the many resources out there to help you manage it! 

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