Food allergy vs Food intolerance

Many people think that a food allergy and a food intolerance is much the same thing. However, there is a big difference and many of us could be intolerant to one or more foods without even realizing it.

We all know someone with a serve allergy. This person will strictly avoid a specific food to avoid running the risks of their throat swelling up, or breaking out in a sudden rash or even full anaphylactic shock which would land them in hospital. However, have you ever eaten a large amount of a specific food and just felt ugh or fatigued or battled with reflux but not been able to pinpoint the cause? In this post we will explore the difference between a food allergy and a food intolerance.

One of the body’s most vulnerable places to invaders and infections is the intestine. Its immune system is the largest in the entire body and over 80% of the immune defence reactions originate from the intestine. Therefore, it uses its immune system to fights off invading agents such as viruses, bacteria, parasites and acts a barrier to foreign proteins from food.

Our body can handle a large variety of different foods in different forms, as long as they are correctly digested. The digested foods must be able to pass through the intestinal cells and barrier for proper absorption to take place. However, due to antibiotics, stress, medicines, infections and environmental poisons the integrity of the intestinal wall can become damaged. When it is damage it is almost like there are little holes in the defence barrier and food particles can slip between the intestinal cells. The immune system views these particles as harmful invaders may then initiate an immune reaction against these food proteins.

Food allergy:

To fight these invaders the body produces antigens. If you have a food allergy, known as a type I allergy, your immune system produces so-called IgE antibodies. These antibodies can lead to an immediate allergic reaction where the symptoms often appear within seconds or minutes of ingesting the allergen. An allergy can be identified by the symptoms mentioned above.

Food intolerance:

An intolerance is also known as a type III food hypersensitivity. This can remain undetected because the symptoms may occur only after a few hours or even days after the consumption of a particular food. Due to this delayed reactions it can be making them extremely difficult to identify the specific cause or food. A food intolerance can present itself with a variety of symptoms.


  • Gastro-oesophageal reflux
  • Constipation
  • Diarrhoea
  • Eczema and dermatitis
  • Flatulence and bloating
  • Irritable Bowel Syndrome (IBS)
  • Crohn’s Disease
  • Migraines
  • Obesity
  • Chronic fatigue

The upside is that you can improve a food intolerance. This will be done by eliminating the specific food from your diet for up to or more than a year. This allows the body’s immune system to rest and the inflammation cause by the perceived invader to reduce. The food will then be slowly introduced and your tolerance monitored very closely.

Your dietician can do an intolerance test to help you figure out which foods are causing an intolerance. Depending on your test results, you will start of a specific step wise plan for an extended period of time. The end goal being to assess if the foods will be safely re-introduced. Therefore, it is very important to consult with a Dietitian when dealing with intolerances. This will avoid you becoming at risk of not meeting specific nutrient requirements with having to cut out certain foods or foods groups. A Dietitian will be able to help create a plan to ensure that you remain healthy, help rebuild your immune system and your gut integrity.