Food Allergies, Food Intolerance and Food Sensitivity, which is which?

Do you have a food allergy or a food intolerance?

If you have recently been put on an allergen-free diet you are most likely discussing the intricacies of your needs with your doctor or dietician, or naturopath and they will tell you the degree of avoidance that is required for your particular needs.

The differences in the dietary needs of a person with an allergy can be significantly different from a person with an intolerance. Hence if you are uncertain which you have or you are at all confused about the parameters of your diet, you definitely need to see your doctor for clarification.

The words generally used to describe adverse reactions to foods:

Food allergy is when your immune system is involved in your reaction to food. Food allergies can be life threatening.

 Food intolerance is a reaction to a food that doesn’t involve your immune system.

 Food sensitivity is the general term for an adverse reaction to a food (that is it refers to both food allergies and food intolerances).

  Food Allergy

 Virtually any food can produce an allergic reaction (Porth, 2007).

 Allergic reactions to foods can be:

  • Acute (immediate)
    • Anaphylactic – life threatening
    • Hives
  • Chronic (occur over a longer time frame)
    • Asthma
    • Atopic dermatitis
    • Gastrointestinal disorders

(Porth, 2007)

 For information on food allergies check out this link:

For more information on anaphylaxis please go to:

 Non-anaphylactic allergies can still cause wide-spread damage to the intestines and result in nutrient loss (through reducing the absorptive surface of the intestines) and causing other health problems.

 Food intolerance

Food intolerances are not allergies or a dislike of certain foods. There are various reasons for food intolerances, some may be caused by:

  • Metabolic disorders
  • Pharmacological or drug like reactions
  • Idiosyncratic reactions (eg. an unusual or unexpected reaction).

(Wahlqvist, 1997)

Foods which commonly cause sensitivities

  • Milk and milk products
    • Usually to the alphas1 casein
    • beta-lactoglobulin and
    • Maillard browning reaction products
    • Contaminants found in milk (eg. fodder consumed by the cow, penicillin residues in milk following mastitis treatment)
    • Amines found in matured cheeses
  • Egg
    • The albumin in egg white
  • Legumes
    • Peanuts
    • Soy beans
    • Castor beans
  • Nuts  and seeds
    • Walnuts
    • Pistachio
    • Sesame seed
    • Brazil nuts
    • Almonds
  • Shellfish
    • Crustaceans
    • Molluscs
  • Fruits and vegetables
    • Tomatoes
    • Grapes
    • Bananas
    • Strawberries
  • In addition food sensitivities may also be caused by;
    • Carbohydrates (eg. sugars)
    • Lipids (fats)
    • Proteins (described above)
    • Food additives:
      • Colours
      • Flavours
      • Preservatives
    • Salicylates
    • Amines

(Porth, 2007; Wahlqvist, 1997)

Typical symptoms of food sensitivity include:

  • Diarrhoea or Bloody diarrhoea
  • Vomiting
  • Abdominal pain
  • Impaired growth
  • Hay fever or sinus
  • Asthma
  • Breathing difficulties
  • Hives
  • Rashes
  • Eczema
  • Swelling
  • Behavioural changes
  • Headaches
  • Fatigue
  • Irritability
  • Depression
  • Muscle and joint pain

(Wahlqvist, 1997)

I’ve read many articles that say that people are more willing to believe they have a food sensitivity than actually occurs, however, with the list of symptoms generated by food sensitivities being so vast, and the mechanisms that cause food sensitivity also being variable and by no means fully defined or understood, it seems presumptive to assume that people aren’t really as sensitive to food as they believe they are. Especially as new research emerges for example this article.

What to do if you think you have a food sensitivity (allergy or intolerance)

If you believe you have food sensitivity, you should see your doctor so he or she can determine if you have an allergy or intolerance or if your symptoms are due to another underlying condition as a number of other conditions can be responsible for the symptoms above, your doctor is the best person to determine that. Also, some food allergies (eg. Coeliac) may not be detected if you have been eating a gluten-free diet before getting checked out, so it is important you see your doctor first.

If you have identified a food sensitivity generally the treatment is avoidance of that food, which can be quite hard for some people who are very very sensitive as they can react to:

  • Trace amounts in the foods
  • Trace amounts occurring from foods being in contact with the allergen during processing even though the final food might not actually contain the allergen.
  • Trace amounts from the foods due to preparation, eg. making a nut free dip in a bowl that previously held peanuts can be very dangerous for someone with an anaphylactic response to peanuts.
  • Kissing someone who has eaten that food
  • The smell of the food

It is important to understand your food labels ( and also looking here) and the level of sensitivity of the person you are preparing food for when it comes to food sensitivities so you are avoiding their allergens to the right degree.  


Allergy facts about anaphylaxis, allergies and intolerance, labels and all other important information at

Porth (2007) Essentials of Pathophysiology: concepts of altered health states (2nd Edition). Lippincott, Williams & Wilkins, Chapter 15.

Wahlqvist (Editor)(1997) Food & Nutrition, Australasia, Asia & The Pacific. Allen & Unwin, Australia, Chapter 43.