Food Allergies Explained

ADVERSE REACTIONS TO FOOD are classified as being either TOXIC or NON-TOXIC.

TOXIC Reactions occur when there is Food Poisoning.





Thus a food allergy involves the immune system, and occurs when a food to which one is allergic (= food allergen), is consumed causing the body to release histamines.

Only a very small, miniscule amount of the food allergen needs to be consumed, in order for the allergic reaction to happen.

On the other hand, a food intolerance occurs when there are problems digesting the food, e.g. when the colon is not producing sufficient amounts of a specific digestive enzyme, and thus usually colon discomfort / symptoms occur when that specific food is consumed.

SYMPTOMS OF FOOD ALLERGIES (can be acute and / or chronic)

** Reactions can be either immediate OR delayed by 4 – 24 hours **

If one is allergic to one or more food allergens, the histamine response can affect one or more of the following 3 organs:

  • The SKIN: presenting with a rash / urticarial / eczema
  • The GASTROINTESTINAL TRACT (digestive system): presenting with oral allergy syndrome / nausea / vomiting / diarrhoea / abdominal pain / cramps etc.
  • The UPPER RESPIRATORY TRACT: presenting with symptoms such as rhinitis / otitis / shortness of breath / asthma / and in severe cases anaphylactic shock which is potentially fatal.


  • Wheat
  • Gluten
  • Cow’s Milk
  • Egg
  • Shellfish
  • Fish
  • Tree nuts
  • Peanuts
  • Soybean
  • Citric Acid
  • Practically any kind of food containing even small amounts of protein can cause an allergic reaction in sensitive individuals.
  • Hidden allergens can occur in processed foods, and must by law be indicated on the Food Labels.
  • Small doses can trigger a reaction.
  • Food allergies that occur in children are usually outgrown after a few years if the food(s) is effectively eliminated from the diet. (Antigen-dependent: peanut, fish & tree-nut allergies seem to persist, while egg, milk and wheat allergies seem to disappear).


  • A person allergic to one food CAN (but does not necessarily) also show reactivity to foods belonging to the same biological family.
  • Allergy to one member of a plant food family frequently results in a variable degree of allergy to other members of the same family.  Example: a person allergic to peanuts MAY also be allergic to peas and other legumes. The most well documented cross- reactivity is the one which occurs between apple and birch pollen.
  • Note: foods contain a lot of different allergens, and one can be sensitized to one OR a few of these.  ALSO one food might contain the same allergen as another, although it is never certain that one will react clinically to both foods…… therefore not all apple-allergics are necessarily allergic to birch pollen.
  • It is still important to know about the various plant families; as well as to be aware of claimed cross-reactions.


GRASSMillet, corn / maize, sorghum, sugar cane, rice, oats, barley, rye, wheat
LEGUMEArabic gum, tamarind, Senna, carob bean, fenugreek, alfalfa, tragacanth, guar, liquorice, peanut & groundnut, broad bean, lentil, pea, chickpea, beans (various), soy bean
ROSEPrunus: almond, apricot, cherry, nectarine, peach, plum
Rubus: blackberry, loganberry, raspberry
Fragaria: strawberry
Pyrus: pear
Malus: apple
CITRUSOrange, grapefruit, lime, lemon, naartjie, mandarin
CRUCIFERAEBrassica: broccoli, brussel sprouts, cabbage, cauliflower, kohlrabi, mustard (black), rape seed, turnip
Sinapis: mustard (white)
Raphanus: radish
Nasturtium: watercress
LILYAllium: onion, leek, garlic, chives
Dioscorea: yams
POTATOPotato, tomato, paprika, bell (sweet) pepper

Treatment of any Food Allergy involves:

  1. Excluding the food allergen in any form.
  2. Following a balanced diet, whilst avoiding certain foods (that may even include staples), best prescribed and planned by a Registered Dietician.
  3. Understanding and reading Food labels. Developing a “safe foods” shopping list. Finding out those places close to you that stock allergen-free foods.
  4. Being willing to experiment with new foods and new recipes, should a common food now need to be excluded.

Note: most major supermarket chains produce shopping lists for allergy sufferers showing the brands to avoid, and those safe to include.

Allergy to SOY is rare, with only 0.5% of the World’s population actually suffering from this.

However where there is a definite clinical allergy to soy, it is vital to understand the following information:

A soya allergy is an adverse reaction to the protein fraction of the soybean.

The soybean is classified as a legume.  Allergy to one legume might (but are often NOT) also be associated with allergy to another legume. This is known as cross-reactivity. (# refer to food list)

Other legumes include: red kidney, white, lima, navy, string and pinto beans; peas; lentils; chick-peas; peanuts; carob; licorice.

Soybeans can be fresh, processed into soybean flour or processed for oil.

Soybean oil is used in some salad oils, margarines and in industrial components (linoleum and glue in the plywood industry).

Soy sauce (shoyu) is a fermented product of soybean and wheat.

Soybeans can be “hidden allergens” as substitutes for meat or when added to improve the storage stability and/or the protein value of bread.


Soya beans Soya sauceSoya sproutsSoya flour
Soya oil # Soya milk Soya bean curd (Tofu)Soya lecithin
Soy noodles/pastaTempehMisoSoy protein isolate
Hydrolyzed soy proteinVegetable starch*Vegetable gumsVegetable shortening#
Hydrogenated oils#TVP (Texturized Vegetable Protein) / Meat substitutes

* Check the type of starch used.

# Tolerated by most people with soya allergy. Caution is advised for those with history of anaphylaxis.

HIDDEN INGREDIENTS: – look out for – (avoid skin contact)

  • Varnish
  • Paints
  • Blankets
  • Candles
  • Cloth
  • Massage creams
  • Adhesives (e.g. glue used in plywoods)
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