The science of nutrition and healthy eating
The science of nutrition and healthy eating

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2 Food intolerance

Food allergy is an allergic response causing food hypersensitivity. It is much less common than food intolerance which is sometimes called non-allergic hypersensitivity.

Food intolerance does not involve the immune system. Symptoms often occur slower than with a food allergy. The delay can make it difficult to identify the particular food that has resulted in the symptoms.

The symptoms can last for hours or even until the next day. Often there is intolerance to more than one food, which again can make identification difficult. Also, symptoms only occur if a reasonable amount of the food is eaten. With an allergy, traces of it can trigger a reaction.

Common food intolerances include:

  • lactose found in dairy products which may be due to lactase deficiency (the enzyme that breaks down lactose)
  • gluten found in wheat products and added in some processed products
  • wheat contains gluten and some products contain traces as they may be produced in areas where wheat of gluten is produced
  • caffeine found in coffee, tea, coke and added to other products
  • histamine found in quorn, mushrooms, pickled and cured foods, and alcoholic drinks. Histamine is a natural component of the immune system but overproduction can contribute to anaphylaxis
  • vaso-active amines e.g. those found in red wine, strong and blue cheeses, tuna, mackerel and pork products. It is overproduction that can cause intolerances, as it is a chemical naturally found in healthy humans.
  • chemical naturally occurring foods (e.g. salicylates, a family of plant chemicals and glutamate, the building block of all proteins)
  • food additives, especially benzoate and sulphite preservatives and monosodium glutamate (MSG).

Activity 3 Foods that may cause intolerance

Timing: Allow approximately 10 minutes.

Look in your kitchen cupboards and food storage areas and make two groups of products:

  • one containing lactose, gluten, wheat or MSG
  • one that does not contain these ingredients.

Which group is the largest? Click ‘Save’ when you are satisfied with what you have written.

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You may find that many foods contain these ingredients and it may be difficult to have a variety of foods to eat that do not contain them. Often, people who suspect they have food intolerance eliminate the foods because the symptoms can cause distress. So they may end up eating a restricted diet which could cause malnutrition.

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