Was it something you ate?

By Sabine Spiesser BS, Grad Dip Dietetics

Reactions to food

Many people with CFS believe that they react adversely to some foods. Although there are no good statistics about this, the experience of dietitians in the field, and information from the ME/CFS Society of SA, suggests that possibly 20 to 30% of people with CFS are so affected.

There are many ways that food can cause reactions, including true food allergy, and more commonly, a drug-like intolerance to natural or added food chemicals. Some people with CFS may also experience problems with maldigestion or malabsorption of food.

A true food allergy can be life-threatening in some cases. Most reactions however, are less severe. Neither food allergies nor food intolerances are trivial, as they can cause tremendous discomfort for sufferers.

Types of reactions to foods:

Food allergy

Food intolerance or pharmacological reactions

Histamine intolerance

Food indigestibility

Food poisoning

Enzyme deficiencies

Coeliac disease

Food aversion

Food allergy

A true food allergy (any adverse reaction to a food or food component) involves the body’s immune system. This occurs when a food allergen, which is usually a protein or sequence of amino acids, enters the body and stimulates food-specific antibodies known as IgE antibodies. These antibodies are located on the outside of Mast cells or basophils, which are part of the immune system, and when stimulated, trigger these cells to release histamine, thereby causing the symptoms. Some allergic reactions can occur when substances attach to proteins and form an allergen, e.g. nickel allergy.

Not all reactions are due to contact with allergens. Mast cells can also respond to other stimuli, such as heat, cold, exercise etc.

Allergens and antibodies are food specific, just as lock and key are specific for each other. The severity and location of a reaction depends on the amount of food eaten, the form of the food, food processing, exercise, and the quantity of histamine and other chemicals released. Sometimes minute traces of food left on equipment or contaminating other foods can cause very severe reactions. Everybody with a food allergy should have a written INDIVIDUAL ACTION PLAN developed by their doctor. Do not assume that all doctors are familiar with food allergies, anaphylaxis or other food reactions.

While most allergic reactions to food are relatively mild, a small percentage of food-allergic individuals have severe life-threatening reactions. Anaphylaxis is a rare but potentially fatal condition in which several different parts of the body experience food-allergic reactions simultaneously, causing hives, swelling of the throat and difficulty in breathing. Affected people need to carry syringes loaded with epinephrine (adrenaline) for immediate self-injection (Epi-Pen) as well as medic alert bracelets.

Reaction time varies from a few minutes (early) to a few hours (delayed) to a few days (late response). In anaphylaxis an immediate type of reaction is often followed by a delayed one, making a visit to an emergency centre vital.

Anaphylactic shock is the most severe allergic reaction, involving many organs of the body, including the:

Nose – 

sneezing, blocking, watering and runny nose

Upper airways – 

swelling of the throat and vocal cords leading to obstruction of breathing, blue lips indicating oxygen deficiency

Lungs – 

wheezing and asthma

Skin – 

itching hives (urticaria)

Circulatory sytem – 

a fall in blood pressure and collapse

Food allergies and intolerances can cause range of symptoms in different parts of the body, including:

Gastrointestinal system: Abdominal bloating, flatulence, cramps, pain, colic, nausea, vomiting, diarrhoea, anorexia (loss of appetite), early satiety, rectal burning, IBS. Food allergy may be a cause in about 10% to 15% of colicky infants.

Skin: Itchy rash, redness, eczema, hives, welts, local swelling.

Respiratory system: Coughing, wheezing, asthma , nasal congestion, itchy and runny nose, sore throat, hay-fever, difficulty speaking.

Face: Itching eyes, swelling of lips, throat and tongue.

Cardiovascular system: Rapid thumping heartbeat, dizziness, fainting, collapse, low blood pressure, pale & floppy infant.

General: Anaphylaxis, fatigue, fever, flushing, sweating, muscle aches.

Neurological: Headache, irritability, dizziness, faintness, drowsiness, loss of consciousness, hypoglycaemia type symptoms.

Symptoms of a food allergy are highly personal and usually begin within minutes to a few hours after having eaten the offending food. Immediate reactions are usually obvious, but any other reaction needs further investigation. Usually, people are truly allergic to only one or two foods. Food allergy is more common in children, and many children grow out of their allergies over time.

The most common food allergens are milk, soy, wheat, egg, fish, shellfish, peanuts, and tree nuts such as walnuts. However, all foods contain proteins, which can potentially act as antigens. Sometimes patients allergic to latex also react to certain foods such as avocados, bananas, kiwis or chestnuts. Reactions are also possible between botanically related or unrelated foods. This is termed Cross-Reactivity.

In Oral Allergy Syndrome, individuals react to uncooked foods with mouth and throat itching or swelling. Fresh fruits, nuts and vegetables are often the culprits. These reactions are brief and believed to be due to pollen protein cross-reacting with proteins found in fruits and vegetables. Often reactions are to other members of the same botanical family. The responsible proteins (profilins) are inactivated by cooking. For example, persons sensitive to birch tree pollen may react to fresh apples. The same people, however, might tolerate cooked apples, as in apple sauce. More serious allergic reactions can occur, if exercise is undertaken soon after eating a lot of this type of food. Occasionally individuals are allergic to many different fruits and vegetables.

Examples of cross-reactivity:



Ragweed pollen 

Melons, banana, chamomile

Birch pollen 

Apple, carrot, hazelnut, potato, almond

Mugwort pollen 

Celery, apple, kiwi


banana, kiwi, avocado, chestnut

Exercise Induced Anaphylaxis: in this condition, individuals develop itching, rashes, angioedema and upper airway obstruction with bronchospasm during or shortly after strenuous exercise taking place within a few hours of eating certain foods. This allergic condition may occur up to 12 hours after eating wheat, celery and shellfish, especially prawn. These patients have no reaction to the foods if at rest.

Food intolerance

Food intolerance is an adverse reaction to food which does not involve the body’s immune system. These reactions are called “pharmacologic reactions” because the culprit substances behave like drugs, possibly acting on the nervous system. In adults, this sort of reaction is far more common than true food allergy, and seems to be increasing.

The symptoms of pharmacological food intolerance can be the same as symptoms of food allergy eg hives, swelling, eczema, headaches, asthma and other respiratory tract symptoms, bowel symptoms, and cognitive disturbance.

The severity of the reactions depends on the dose eaten, as well as other chemicals consumed at the same time, and other factors such as stress , hormone levels (eg women often are more reactive before menstruation), and use of other medications (especially NSAIDs). Food intolerance reactions can be caused by both added and natural substances in foods. Most people have no problems consuming these natural food substances and additives – reactions occur in individuals who happen to be more sensitive. Reactions are becoming more common to the increased ingestion of these substances in processed foods. Common offenders are:

Amines: histamine, tyramine, tryptamine, serotonin, dopamine, phenylethylamine Present naturally in foods and produced during fermentation, aging and storage in other foods.

Salicylates: aspirin-like compounds present in a wide variety of herbs, spices as well as fruit and vegetables. Reactions to these may be even more common than reactions to artificial colours and preservatives. Salicylates are concentrated in the surface areas of fruits and vegetables and levels decrease as the fruit ripens. Tea contains very high salicylate levels.

Glutamates: (E 620-623) MSG stimulates nerve endings, perhaps accounting for its function as a “flavour enhancer,” amongst other properties. MSG is the sodium salt of glutamic acid, an amino acid found naturally in the human body and in all protein-containing foods such as cheese, meat and milk as well as some vegetables, without causing reactions.

Sulphites: (E 220-228) these chemicals are commonly found processed fruits, vegetables, meats/fish/poultry products, alcoholic and fruit drinks. They are sprayed onto foods to keep them fresh and prevent discoloration or browning. Their use is widespread and cannot be listed here. Sodium metabisulphite (223) is commonly used as a flour treatment agent.

Benzoic acid and Parabens: (E 210-219) benzoates are both a preservative, and also occur naturally in many plant foods (e.g. berries, concentrated tomato products, spices).

Sorbates: (E 200-203) a preservative used in a wide variety of foods.

Food Colourings: (E 100-180) this includes all the artificial colours, as well as the natural colour, annatto (code 160b).

Antioxidants: (E 319-321) Butylated hydroxyanisole (BHA) and Butylated hydroxytoluene (BHT) are found in high-fat foods to prevent rancidity as well as some cereals.

Nitrates and nitrites: (E 249-252) used as a preservative in processed meats and some cheeses.

It can be very difficult for people to identify food intolerances, because reactions can be inconsistent (depending on the dose eaten), can be delayed and build up over many days, individuals can react to several different food chemicals, and each food chemical can be found in many different foods, all contributing to the total dose.

Food ingredients possible of causing allergy or gut irritation:

Meat tenderiser, Papain, can cause allergy and food intolerance (Processed meat products.

Irritant substances in foods such as paprika and chilli (capsaicin) or stimulant effects of naturally occurring substances in food such as caffeine in coffee and tea.

Gums (E 400-418) (agar, guar gum, tragacanth, carragenan, xanthan gum) can cause abdominal distension and bloating when consumed in large quantities.

Anaphylactoid reactions

Anaphylactoid reactions to food chemicals are anaphylaxis-like reactions, but don’t involve antibodies. Metabisulphite or sulphur dioxide induced asthma is an example of such a reaction.

Histamine intolerance

Histamine, and histamine-like substances called amines, occur naturally in foods, and can trigger symptoms that mimic allergy. This is particularly true of fermented foods that contain high quantities of the vasoactive amines such as Histamine, Phenylethylamine, Serotonin, Tyramine, and Dopamine. Vasoactive substances affect the diameter of blood vessels (vasodilating = widening, vasoconstricting = narrowing). Amines can act directly on small blood vessels to expand their capacity, perhaps accounting for their effects such as flushing, migraines and nasal congestion in some patients. Common symptoms of vasoactive amine ingestion are abdominal cramping, flushing, headache, palpitations and hypotension. [see chart of foods containing vaso-active amines, below] The symptoms are usually dose related, and occur when the enzyme that metabolises amines, diamine oxidase, does not work well enough to metabolise the amines ingested, or to handle high levels of amines when eaten in large amounts. Symptoms are worse in sensitive people with low levels of enzymes or if alcohol is consumed at the same time. Certain food chemicals such as benzoates, HBA, HBT, the food colour tartrazine, salicylates, nitrates and sulphites can inhibit these enzymes.

Foods containing vaso-active amines






Cheese (yellow, ripened)
Chicken liver
Eggplant / Aubergine
Fish (all – fresh, frozen, canned)
Meat (all processed)
Soya, Soy products (fermented)
Tomato sauce/puree
Wines (all)

Beans (fermented)
Bovril, Bonox
Yeast extracts (Vegemite, Marmite)
Cheese (ripened)
Chicken liver
Fava beans, broad beans
Meat (cured, processed)
Milk (dried)
Orange, citrus fruit
Pickled herring
Soy sauce, Miso, Tempeh

Fava beans, broad beans

Octopus, squid

Cheese (yellow)
Cherry/Raspberry pie filling
Red wine
Redcurrant pie filling
Strawberry (canned)



Histamine-releasing foods

Enzyme inhibitors



Citris fruit

Raw egg white
Citris fruit
Pork meat

The food colour tartrazine


Certain non-histamine containing foods, and food chemicals, can trigger direct histamine release from Mast Cells. IgE is not involved in the reaction and specific IgE antibodies to these foods are not elevated. Foods that have been implicated in this type of reaction include: raw egg white, shellfish, strawberries, chocolate, citrus fruit, pineapple, tomatoes, alcohol, fish and pork meat, as well as salicylates and metabisulphites. The histamine liberated in this reaction will cause symptoms that may mimic true food allergy.

Food indigestibility

Certain food components, when ingested in large amounts, cannot be digested properly and end up in the large intestine where bacteria feed on them. This can lead to bloating, flatulence and diarrhoea. The most common culprits are fructose and the sugar alcohols, sorbitol, xylitol and mannitol.

Food poisoning

Food poisoning is caused by plant toxins such as aflotoxins in mouldy peanuts or soya beans, and bacterial micro-organisms in food, such as salmonella in chicken and bacterial toxins in uncooked meats and certain fish. In some instances, food poisoning can mimic an allergic reaction. For example, in scombroid fish poisoning, spoiled tuna or other fish contain large amounts of histamine produced by contaminating bacteria. When the spoiled fish is consumed, symptoms develop that closely resemble an allergic reaction to food.

Enzyme deficiencies

Enzyme deficiencies may sometimes be mistaken for food allergies or intolerances. However, it is important that they are distinguished from food allergies, to enable appropriate treatment.

Lactase deficiency causes an inability to digest the milk sugar, lactose, causing diarrhoea if too much milk is consumed.

Sucrase-isomaltase deficiency causes an inability to digest sugars, causing diarrhoea if sugar is eaten.

G6PD deficiency causes a serious reaction to Fava beans.

Coeliac disease

Coeliac disease is an inherited immune disease, which does not involve IgE. In coeliac disease, the intestinal mucosa is damaged (flattened villi) by exposure to gluten, a protein found in wheat, rye, barley, oats, triticale and all their products. Diagnosis is by endoscopy and biopsy, after screening tests (Antigliadin IgG, IgA and antiendomysial antibody tests). The only treatment is life-long complete avoidance of all gluten containing foods. This is vital in the prevention of gastrointestinal malignancy. Coeliac disease symptoms include diarrhoea, abdominal distension, failure to thrive, weight loss and occasionally nausea and vomiting. Coeliac disease is usually diagnosed in early childhood but may be first diagnosed in adults. Adults can present without the usual symptoms, fatigue being at times the only sign.

A negative small intestinal biopsy rules out coeliac disease if it was done while consuming a high gluten diet. It is still possible to be allergic or intolerant to wheat, and not have coeliac disease, as wheat contains a large number of proteins, every one of them potential allergens.

Food aversion

Food aversion is a psychological condition where a person has a reaction, caused by emotions associated with food. This reaction does not occur if the food is given in a disguised form.

How are food allergies diagnosed?

Food Allergy Testing

The most commonly used diagnostic test in Food Allergy is Skin Prick and RAST (blood test) with Food Allergens. The negative predictive value of food allergy testing is good – if a test is negative, then there is a 95% chance of there being no allergy to that food, but the positive predictive value is less specific – a positive test requires a challenge with the food for diagnosis.

Skin prick tests have no place in the diagnosis of food intolerances.

Food intolerances are diagnosed by an elimination diet, followed by food challenges and gradual re-introduction of foods and food chemicals. Make sure to seek help from a dietitian familiar with this process, and who hopefully is familiar with CFS. The type of elimination diet depends on your symptoms and the severity of your reactions.

Before you make an appointment, be sure to keep a food and symptom diary, preferably in table format. Record every bite and sip crossing your lips. This is most important in tracking possible patterns. It also helps to rate the symptoms, as you can easily forget how severe the symptoms were when you feel better. If you are accurate in portion size and food description, you could have your food intake analysed for nutritional adequacy. It is vital to keep a diary while challenging and re-introducing foods. Always make sure the dietitian is accessible (phone or e-mail) in case you need assistance.

Follow the diet strictly without interruption. If your symptoms do not start to improve within 14 to 21 days, re-introduce foods. You can then eliminate the foods eaten during the diet to make sure they were not the culprits. If symptoms persist, other causes need to be looked into. Some people experience ‘withdrawal reactions” in the first week on an elimination diet but improve after that, so don’t give up too soon! Sensitivity to fumes and other environmental chemicals may also increase during this time.

It is important to emphasize that “elimination diets” are prescribed like we do a medication: short term, under supervision, and only for very good reasons. Long-term restricted diets are dangerous and can lead to malnutrition, particularly in children.

Sample Food Diary


Food eaten


Brand names
























































































































Treatment in food allergies requires the complete elimination of culprit foods, and the use of antihistamines and other medications as prescribed by the doctor. In food intolerance, the reactions are dose dependent, and the tolerance level needs to be established. Fortunately, the tolerance level can gradually be increased over time. It is vital that you seek help from a dietitian in developing an eating plan as well as making food choices to prevent Hidden Food Allergens. Foods labels can contain a variety of names for a specific food. Foods can be contaminated by unknown foods. Never be satisfied with the statement: “you need to just eliminate xyz.” Detailed instructions of which foods to include/avoid as well as possible hidden allergen sources are vital. If major foods are eliminated, a dietitian will need to offer advice on how to obtain the missing nutrients.

Web sites to browse

FACTS: Food Anaphylaxis Children Training and Support Association

Australian Society of Clinical Immunology and Allergy

Great Web site to search for any info related to allergies

American organization for patient support

Information and support for celiacs

Dr Stephen Bennett’s Web site on health quackery

Up-to-date medical information

Lots of links to allergy Web sites

Information on milk allergy and lactose intolerance

Books to read


J. Brostoff and Linda Gamlin, Bloomsbury, The Complete Guide to Food Allergy and Intolerance. London, Bloomsbury, 2000


John Emsley, Peter Fell, Was it something you ate? Food intolerance, what causes it and how to avoid it, Oxford University Press, 1999


Ardys Zoellner, The SNAK (Sensitive New Age Kitchen), 80 recipes FREE of dairy, wheat, eggs & sugar), available through FACTS


Maurice Hanssen. The new additive code breaker, Lothian books, 1999


AR Swain, VL Soutter, RH Loblay, Royal Prince Alfred Hospital Allergy Unit Friendly foods, Murdoch Books, 1998


Joan Breakey, Are you food sensitive?

The individual action plan should include detailed instructions on...


Removing the trigger.


Giving antihistamines.


Watching for danger signs.


When and how to seek medical assistance.


Injecting adrenaline if needed.


Resuscitation – first aid course.


Observation for relapse under medical supervision.


Written information to inform medical staff.


Wearing a Medic Alert bracelet.


This article has been written for people wanting to obtain some general information of food induced reactions. Readers are cautioned against self-diagnosis and self-treatment based on the limited information provided. This article is not a substitute for professional assessment by allergists/immunologists or dietitians. If you suspect that you might be reacting to food, please consult a specialist. No responsibility is taken by the author for the consequences of treatment initiated by patients who have not been seen by me in consultation. The knowledge in this document reflects general current knowledge and may become outdated as new research information surfaces. Many of the symptoms mentioned in the paper are not specific to food reactions, but general symptoms experienced in a variety of organic diseases. I strongly advise individuals to consult their doctor for a thorough medical check-up prior to any further investigation.

Sabine Spiesser

Sabine Spiesser is a dietitian with a private practice in Melbourne. Her special fields of interest are food intolerance/allergies, gastrointestinal problems and eating disorders. She has had CFS/FMS for many years.

For appointments please call:

Glen Waverley Dietetic Consultancy
Ph: (03) 9561 5342

Sabine has just started up her own Web site:

©Sabine Spiesser
April 2001



This article appeared in the June 2001 issue of Talking Point

Copyright ME/CFS Australia (SA) Inc

Reprinted from http://www.sacfs.asn.au/