Food Allergies

Allergies and Reactions to Food

General Reactions

Specific Reactions

Understanding Food Allergies

Non allergic reactions


Coeliac Disease

Aversion to a food

Common Food Allergies.

Other food allergies.

Protect yourself from food allergies.

Concealed allergens in food products


Allergies and Reactions to Food

There is often confusion between the terms allergy, intolerance and sensitivity. Many terms are used to mean an unpleasant or untoward reaction to something in our diet.  We can be hypersensitive to a food or product - that means that we 'over-react' to it or that our bodies are particularly sensitive.


General Reactions - Certain toxic substances present in foods can cause a reaction in anybody who eats them and to avoid being poisoned the secret is in the time of harvesting (eg Jamaican Akee is poisonous if harvested too early before the pods open naturally); or in the preparation of the food (eg cassava needs seeping and washing; or dragon fish needs special filleting to remove the dangerous part)


Specific Reactions - Other food reactions are dependant on the person ingesting the item and these can be allergic or non allergic


Allergies are reactions to particular substances and characterised by antigen / antibody mechanisms (see below) a classic example is Peanut allergy where exposure can induce anaphylactic shock requiring emergency medical treatment.


Non Allergic reactions can include food intolerance which means that the body cannot tolerate or cope with certain substances - often due to the absence of enzymes required for their breakdown or digestion. An  example is alcohol intolerance caused by absence of the enzyme alcohol dehydrogenase - this condition is common in Native American peoples and in Australian Aboriginals and many far eastern populations. Lactose intolerance is also in this group .

Gluten intolerance is a mixed syndrome whereby gluten sensitivity can be a true gluten allergy (to the gliadin portion of grain) combined with an intolerance caused by the destruction of the lining of the intestinal wall.


Coeliac disease is not an allergy to gluten it is an  intolerance which is partly  inherited and part of an autoimmune sydrome. It is thus allied to diseases like diabetes, thyroid problems and some types of arthritis. Coeliac sufferers can also be coincidentally allergic to gluten, they can also show lactose intolerance as a secondary effect due to damage of the intestinal wall.


Aversion to a food is a psychological condition whereby a patient is repulsed by a food or is mistakenly convinced that they are allergic to a food. Reactions can be extreme and can be linked to an abusive incident or traumatic past event. It can also be part of a wider pattern of eating disorder.


Understanding Food Allergies

There is often confusion between the terms allergy, intolerance and sensitivity. It is important to realize that an allergy is a specific condition. It is diagnosed by looking for specific signs and symptoms and carrying out tests – it is NOT a condition which is diagnosed by ‘exclusion’ (what doctors say if they cant find anything else to explain a patients symptoms)

An allergy to a substance means that part of that substance, a protein component acts as an ‘allergen’ and provokes an ‘antibody’ response in our bodies. Once an allergic reaction has occurred and the antibody production has been provoked, subsequent exposure to that same ‘allergen’ will provoke a quicker and bigger antibody production. Hence an allergic reaction can become more severe at each subsequent exposure. The presence of the specific antibody to an allergenic substance (which is a specific gamma globulin or IgE) can be detected in the blood and forms the basis for allergy testing using blood tests. 


When antigens enter the body the plasma cells produce antibody. These antibodies attach themselves to cells where damage can occur. Mast cells contain histamine and heparin granules (black spots on diagram) Antibody reaction on the mast cells provokes histamine release which causes allergic reactions such as itching swelling urticaria, sneezing etc.

It has been thought that food allergies afflict less than one percent of our population but as testing has become more available it has become clear that food allergies are more common than most doctors believe. Nevertheless, it is important not to try to ascribe all symptoms and vague malaise to food allergies and you are advised to consult your doctor for advice on symptoms before putting them down to a food allergy. Importantly a food allergy may occur in combination with another disorder or may be masking another disease. Get checked out and be safe.

Allergens, or substances which provoke an allergic reaction, may do so by contact with the skin or mucous membranes (lining of respiratory, alimentary and genitourinary tracts) causing dermatitis, eczema urticaria (hives) and other rashes and irritations. They may also be inhaled causing asthma, wheezing and obstruction of the larynx and breathing passages.  However eating or ingesting an allergen will often mean that a bigger amount enters the body and passes to the bloodstream hence causing a more severe reaction. Thus reactions from a food allergy are some of the most dramatic and can range from a tingling sensation in the mouth and lips to anaphylactic shock. Anaphylactic shock can be the result of any allergy but most commonly and quickly occurs in the case of allergies to bee or wasp stings or food allergies such as peanut allergy when within seconds the mouth and throat can swell and constrict air passages and without prompt treatment suffocation can occur.

When an allergic reaction occurs and the antigen provokes the antibody response the actual symptoms are caused by chemicals released in the antigen/antibody reaction which ‘transmit’ the reaction – Specific food proteins trigger food allergies. An allergic person's system produces an allergy antibody (IgE) in response to some food proteins. The allergy antibody acts as a fuse that ignites an allergy bomb-allergy cells that release histamine and other natural chemicals that cause allergic symptoms. Histamine can be released anywhere in the allergy-prone victim's body. A food allergy reaction may occur within seconds of ingestion up to four hours later. If a food allergy causes histamine to be released in the lungs, bronchial spasms, wheezing and difficulty breathing can occur. Histamine from food allergies released in the skin cause itching or hives and eczema. Histamine released in the stomach causes nausea. When food allergies cause a histamine release throughout the body, anaphylactic shock may occur.


Common food allergies are:

·         Wheat allergy.

·         Egg allergy.

·         Milk allergy.

·         Peanut allergy.

·         Shellfish and Fish allergy.

Other food allergies may include:

·         Brewer yeast allergy.

·         Corn allergy.

·         Nuts allergy.

·         Bean allergy.

·         Pork allergy.

·         Strawberry allergy.

·         Chocolate allergy.

·         Tomato allergy.

·         Cheese allergy.


·         Wine and beer allergy.

·         Pickle allergy.

·         Baking yeast allergy.

·         Avocado allergy.

·         Coffee allergy

·         Soybean allergy.

·         Oils from peanuts, soybeans, sunflower seeds, sesame seeds, corn.

·         Allergy to food preservatives and seasonings (MSG - monosodium glutamate)

Protect yourself from food allergies:

To help identify your allergies and hence avoid trigger foods - you can of course have blood tests but you can learn a lot by observing timings of reactions. Always discuss findings with your doctor and remember that symptoms like food allergies may also be mimicked or caused by other diseases and conditions which may be serious, may be very treatable and need to be checked out. Treatment of a food allergy can make your life much more enjoyable and give you a great sense of wellbeing but a missed colon cancer, a missed thyroid disease or other problems can be tragic - so do check with your doctor first.

·         Keep a food diary of your eating habits and food allergy symptoms.  Write down everything you eat for a few days and then if you have a hunch as to what might be affecting you - note which days you eat the offending item and which days your symptoms appear. Discuss your diary with your doctor

·         Avoid foods you are allergic to but read food labels carefully. many processed foods have hidden ingredients that can cause a relapse of symptoms.

Hidden food allergy ingredients:

Food labelling is quite comprehensive in most countries but nevertheless it can be hard to avoid some ingredients.

·         Wheat Gluten-A particularly difficult culprit to track down is gluten and wheat products used as thickening in huge numbers of food products - soups, bread, pasta, white flour, white vinegar, alcoholic beverages, cookies and crackers, ice cream.

·         Milk-casein, butter, artificial butter flavor, margarine, cheese, custard, sour cream, yogurt, brown sugar, chocolate, lunch meats, hot dogs, high-protein flour.

·         Eggs-albumen, mayonnaise, salad dressings, sandwich spreads, bread, ice cream.

·         Corn-corn meal, corn syrup, maple syrup, dextrose, flavourings, grits, powdered sugar, vitamin C, plastic wrap, paper cups and paper plates, adhesive on stamps and envelopes.

·         Sulphites (used on raw and processed foods to prevent spoilage and discoloration)-alcoholic beverages, fruit juices, bakery items, pizza crust, waffles, pickles and olives, wine vinegar, horseradish, pickles and pickled vegetables, relish, trail mix and other dried foods, gelatin, frosting, jam and jelly, coconut, gravies, stuffing, noodles, rice mixes, fish and shellfish, sugar, tortilla and potato chips, hard candy, vegetable juices, canned and frozen vegetables.


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