Mechanisms of food intolerance and food allergy

With regard to underlying mechanisms and trigger factors for food allergy and food intolerance, it is fair to say that our level of knowledge is very much in its infancy. We know, for example, that some individuals are more susceptible than others. Atopy (predisposition to allergic disease) is heritable, so could this susceptibility be due to genetic factors What about environmental factors, in particular during infancy What is their impact 4 What role do food allergens themselves play We know...

Occupation and smoking

Respiratory diseases have known associations with those working in the food and food-related industries. These include occupational asthma, occupational rhinitis and hypersensitivity pneumonitis. Skin diseases such as contact dermatitis and contact urticaria are also associated with work in these industries. These diseases are not all Type I, IgE-mediated reactions. Some cases of occupational asthma and some of contact dermatitis occur as a result of irritation.12 Hypersensitivity pneumonitis...

Avoidance therapy 521 General principles

The diagnosis of food-related symptoms should not be taken lightly, as food avoidance can be difficult, expensive, disruptive and even harmful to the health of the patient, especially in infants and young children1 (Table 5.1). The increasing complexity of our food intake and a higher proportion of packaged cooked foods in our diet make the avoidance of a particular food difficult (Table 5.2). The food industry has become increasingly important in the lives of patients with food allergy and...

Open patch test and the diagnosis of contact urticaria

Some food substances can induce an immediate urticarial-type reaction at the point of contact. No standardised test exists for investigating such contact urticaria, but one can demonstrate such a reaction by an open test. The substance is placed on the skin of the flexor surface of the forearm for 30-45 minutes in an attempt to replicate the urticaria. It may be necessary to use non-intact, eczematous skin. This contact urticaria may be secondary to an allergic or non-allergic reaction. In the...

Characteristics of patients with food intolerance

The most widely quoted study is by Parker et al. They were able to divide 45 adults reporting food-related complaints into two groups. The first group of 22 subjects reported reactions to the common allergenic foods - legumes, tree nuts, crustaceans and fish. Twenty-one out of the 22 subjects in this group had positive skin prick tests to the offending food. The second group reported reactions to food such as sugar, wheat, egg, cured meat and yeasts. Only four out of the 23 subjects in group 2...

Collaboration with the food industry retail and manufacturing

Soames's statement that any change in labelling legislation is a European matter is quite true. That prospect was an alarming one for campaigners who were concerned about food-induced anaphylaxis and the risks of allergy sufferers inadvertently coming into contact with lethal ingredients. Soames seemed to be implying that it would be several years before all prepacked food would be adequately labelled and therefore safe. A major point for discussion was the 25 rule governing compound...

The epidemiology of adverse food intolerance

Lack, St. Mary's Hospital, London 10.3 Commonly reported food allergies 10.5 Cross-reactions between foods 10.7 Risk factors for the development of adverse food reactions 10.8 Intervention strategies aimed at preventing adverse food reactions

Novel and uncommon food allergies

There are a number of foods that are eaten in geographically or culturally quite specific populations and adverse food reactions are limited to these groups. However, with diversification of cultures and diets across the globe, particularly in developed countries, adverse reactions to these foods may be seen in many other countries. A good example is sesame seed, to which allergy in Western countries was rarely reported (Rance et al. 1999). However, there are reports of an increasing number of...

Toxic food reactions

Classification Adverse Reactions

In principle, these are reactions which could occur in any individuals if the dose is high enough to trigger a reaction. They are usually caused by direct action of food components without involvement of immune mechanisms. Toxic compounds which trigger such reactions can occur naturally, such as from eating a puffer fish complete with its poison sac Or they can be contaminants of food. Although such reactions are fairly distinguishable from non-toxic food reactions in terms of mechanism, one...

The British Allergy Foundation

The British Allergy Foundation has a broad sphere of interest, encompassing all types of allergy. BAF was formed as a registered charity in 1991 by a group of leading medical specialists who were all determined to improve the awareness, prevention and treatment of allergy. The charity is managed by a board of trustees which deals with all the business aspects of the organisation. All decisions on medical and scientific matters in which the foundation is involved are made by a team of medical...

OAS and pollen allergy

The frequency with which OAS occurs in subjects with pollen allergy is notable. Up to 40 of subjects with birch and ragweed allergy suffer OAS.15 Ragweed allergy is particularly associated with reactions to bananas and melons, and birch allergy with celeriac, apple and hazelnut allergens. The basis of the latter is thought to be homology between the relevant allergens, particularly Bet V 2 from birch, Mal d 1 from apple, and Bet v1 and Apig 2 from celeriac.16 Treatment of pollen allergy with...

Peanuts and tree nuts

Over the last few decades, peanuts have become a ubiquitous part of the Western diet as they are a versatile form of easily digested protein (Lucas 1979). In a study looking at the use of dietary manipulation to prevent the development of food allergy, all infants in the control group were exposed to whole peanuts by their second birthday (Zeiger et al. 1989) occult exposure probably occurs even earlier. Adverse reactions to peanuts and tree nuts are generally IgE mediated, occurring rapidly...

The catering industry

So far I have concentrated on food sold in supermarkets, but it has to be accepted that the greater risks for people with severe allergies lie in catering establishments, where the owners are under no legal obligation to label allergenic ingredients. Most of the known deaths from food-related allergies have occurred when the food was eaten away from home. Although information on near-fatalities is largely anecdotal, it is almost certain that most of these incidents happen when food is eaten in...

Abbreviations

Association for Dietitians in South Africa double-blind placebo-controlled food challenge European Academy of Allergology and Clinical Immunology Food Allergy Research and Resource Program Food and Chemical Allergy Association Food and Consumer Products Manufacturers of Canada FEIA fluorescent enzymatic immunoassay FEV1 forced expiratory volume in 1 second FIDB Food Intolerance Databank (South Africa) FLEP Food Law Enforcement Practitioners GMP Good Manufacturing Practice GPSR General Product...

Nontoxic food reactions

These reactions are either immune-mediated or non-immune-mediated. When the reaction is immune-mediated the term 'food allergy' is applied, and when non-immune-mediated the term 'food intolerance' is recommended. Both types of reactions are reproducible and depend on an individual's susceptibility. Food allergy itself can be subdivided into two categories, IgE-mediated food allergy and non-IgE-mediated food allergy (Fig. 1.1). Immunoglobulin (Ig) E, or IgE, is the main antibody involved in...

Treating the immediate symptoms 551 Acute allergic reactions to foods

Development of symptoms within two hours of ingestion of the suspected food may be reasonably classified as an acute reaction. These reactions are commonly due to milk, egg, fish and nuts (Table 5.6). The person may or may not know the food responsible. In children, allergic reaction may occur to the first known exposure to a food such as cow's milk, egg or peanut. It may also develop in an Table 5.6 Foods commonly implicated in the anaphylactic reactions Tree nuts brazil nut, hazelnut, almond,...

References

1 ISOLAURI E and TURJANMAA K, 'Combined skin prick and patch testing enhances identification of food allergy in infants with atopic dermatitis', J Allergy Clin Immunol, 1996 97 (1) 9-15. 2 SACKETT D L, RICHARDSON W S, ROSENBERG W and HAYNES R B, Evidence-based Medicine, Churchill Livingstone, New York, 1997. 3 METCALFE D D, 'Food allergy in adults'. In Metcalfe D D, Sampson H A and Simon R A (eds), Food Allergy Adverse Reactions to Foods and Food Additives, Blackwell Science, USA, 1997. 4...

The Food and Chemical Allergy Association

The Food and Chemical Allergy Association, based at 27 Ferringham Lane, Ferring, West Sussex BN12 5NB, came into being as a result of a letter sent to a daily newspaper in 1976 by its founder, Ellen Rothera. She had been ill for eight years and came to believe that food allergies due to a malfunctioning immune system were the root cause. She managed to stabilise her condition and make a recovery. Ellen's letter to the Daily Express was not only published, but given a leading position. As a...

Clinical categorisation of allergic reactions

In a series of 62 adults and children with peanut allergy, Ewan18 divided patients into those whose separate symptoms were symptoms involving skin and airway significant fall in blood pressure or loss of consciousness. Out of the 62 patients, 20 had skin changes only, 33 had evidence of airway involvement with laryngeal oedema or wheezing, and nine had evidence of a significant fall in blood pressure.18 The categorisation of laryngeal oedema is discussed below. Contact symptoms are common in...

Hypoallergenic milk formulae7

CMA in the first year of life is one of the most common problems faced by paediatricians. It is mediated by an immune mechanism, whereas cow's milk intolerance is due to non-immunological causes such as lactase deficiency. CMA may affect the gastrointestinal tract, respiratory tract, skin or blood, and systemic reactions, including anaphylaxis, may occur. Avoidance is the mainstay of treatment, and breast-feeding should be actively encouraged. Since intact cow's milk protein can pass into the...

Collaboration with governments

For many years, food allergy and intolerance had a poor public image. Despite the progress made in this field by a small number of dedicated scientists and physicians, allergy found itself on the fringes of medicine, dismissed altogether by some doctors, who regarded it as a convenient scapegoat for undiagnosed conditions that had other, unknown causes. People who claimed to suffer adverse reactions to food were accused of jumping on to an allergy bandwagon. Perhaps these accusations were...

The use of disclaimers on food labels

In February 1994, one of the founder members of the Anaphylaxis Campaign gave a shrewd warning about the possible negative effects of any food labelling campaign companies would begin to take the easy way out by printing disclaimer notices. A leading chocolate company had already begun to include a warning under the ingredient list of two of its brands stating 'May on rare occasions contain nut traces.' And dire warnings were given that this might conceivably catch on. The prophecy has come...

The Dutch Food Intolerance Databank ALBA

ALBA is perhaps the most influential of the food intolerance databanks worldwide. It was established in 1982 by the Agricultural University of Wageningen and became operational in 1984. Since 1988, the databank has been hosted by a division of the government research organisation Netherlands Organisation for Applied Scientific Research TNO , located in Zeist. ALBA currently holds data on around 500 brands and 11 000 products from 150 manufacturers and retail organisations, representing...

Food labelling in Europe an outline

The emphasis of European law at European Commission EC level is on product and consumer safety, together with ensuring the smooth operation of the internal market. The provision of consumer information, enabling consumers to make an informed choice concerning the foods they buy, is also one of the fundamental concepts of current EC law. Such horizontal provisions have generally replaced the concept of harmonisation by control of specific product standards. Labelling requirements are detailed by...

Predisposing factors for anaphylaxis

It is clearly established now that pre-existing asthma may exacerbate or predispose to anaphylaxis. This is clearly in keeping with the concept of the target organ of the reaction being important. Sampson's group of fatal and nonfatal reactors were clearly distinguished by the presence of a diagnosis of asthma, particularly if the asthma was poorly controlled. Our study in Southampton has supported this finding Table 4.4 .10,21 Other factors that may predispose to severe disease are the use of...