Food Reactions

A diverse spectrum

Food reactions Immunological –

IgE &

Non-IgE – T cells, macrophages Non-immunological

Pharmacological- drug-like –dose dependent

Enzyme deficiencies

Food poisoning- Toxic

Immunological Reactions

Non-Immunological Reactions

Prevalence of food allergy IgE mediated allergy1-2.5% of adults6-8% of childrenThe incidence of other types of food

reactions is not known

Systems affectedGastrointestinalRespiratorySkinCardiovascularGeneral-Anaphylaxis

Respiratory reactions Throat tightness Wheezing, asthma Shortness of breath Repetitive coughing Cyanosis- turning blue Nasal congestion Runny nose Cough

Gastrointestinal symptoms Itching, tingling, swelling lips, mouth Tongue & Throat swelling Angio-oedema (swelling, puffiness) Nausea Vomiting Diarrhoea Abdominal pain, cramps Colic , reflux

Skin reactionsPruritus – itchingFlushingUrticaria – rashAngio-oedema- tissue swelling Eczema/dermatitis

Itchy eyes and ears

CardiovascularHypotension – low blood pressureShockSyncope- faintingArrhythmia – irregular heartbeatChest pain

Most common allergenic foods Milk Wheat Egg Soy Peanut Tree nuts Fish & shellfish Any foods can theoretically trigger allergies

Cross-reactions may occur Wheat and other grains Soy and other legumes Cow’s milk & horse, sheep, goat’s milk Different tree nuts Nuts and peanuts Pollen & some fruit Latex and avocado, kiwi, chestnut, banana

Anaphylaxis –food inducedFoods most commonly implicated

EggsWheatMilk PeanutsFish

Shellfish

Nuts

Celery

Seeds

Legumes

Guar gum

Rice

Many others

Exercise induced AnaphylaxisAnaphylaxis occurring after exercise,

when certain foods are eaten prior or after exercising

Common culprits: Wheat,cereals, celery, fruit,vegetables, shellfish

Anaphylaxis – be prepared Carry Epinephrine and learn how to use it Always treat first, then review, never wait and see Know how to find help fast Have an emergency action plan Follow your doctor’s instructions Only eat “safe” foods Let others know about your condition Be prepared, anxiety can cause similar symptoms

Watch out for: “may contain”

“may contain” implies careless manufacturing & preparation practices

“may contain” only reduces the manufacturer’s legal risks

Avoid foods “manufactured on shared equipment”

Don’t assume restaurants are able to prevent cross-contamination

Peanuts – a case to consider If you react to peanutsDon’t ever trust “nuts” they could be de-

and re-flavoured peanutsPeanuts are widely used in the food

industry It only takes a minute grain to reactAsk others to be considerate

Immunological reactions- IgE IgE mediated reactions Onset: minutes to several hoursMast cells, basophilsHistamine, prostaglandins, leukotrinesVasodilation, mucous secretion, smooth

muscle contraction, influx of inflammatory cells

Immunological reactions- non-IgE

Non-IgE mediated reactionsT-cellsMacrophages Cytokines

Food Intolerances Enzyme deficiencies Food poisoning Intestinal fermentation Food aversions

Pharmacological reactions- reactions to chemicals in foods or additives. Reactions are dose dependent and can be cumulative.

DiagnosisSkin prick test for IgE reactionsRAST- blood test for IgE to foodsElimination diet and food challengesChallenges should not be done where

there is a risk of anaphylaxisChallenges require backup emergency

treatment facilities

Hidden allergen avoidanceStudy the pages on different foods to

familiarize yourself with all the possible sources of hidden food allergens

Always read food labelsEat less processed foodsChoose fresh, simple foods

Do the right thing Don’t just restrict your freedom of eating a

wide variety of foods Do seek professional help to investigate the

symptoms you have. The cause may not always be what you think! Remember- it can take up to 36-48 hours for

some reactions to develop – even longer in some conditions