ABSTRACT
The cultural patterns of food consumption tend to change gradually with time. Although it is true that technology increasingly secures the safety of nutrients, this does not mean that 184each food product is safe. In fact, with the introduction of food additives such as coloring agents and preservatives, the number of substances that may generate adverse reactions has increased, and it seems that the incidence of allergic reactions has, too. This may be explained by developments in technology such as high-temperature processing and irradiation of food, leading to the creation of new antigenic sites. Other factors may be involved as well. It is known, for example, that allergy to inhalants is on the increase. There are many mechanisms underlying adverse reactions to foods. Because of their complexity, there has been confusion about the terminology that should be applied for the different kinds of adverse food reactions. A lack of consensus can easily lead to misunderstanding. Therefore, a discussion about this problem has been started and this has led to the much wanted result: the term adverse food reaction has been defined as any kind of abnormal response to a food (product). This can be an immunologically mediated response or food allergy, or a non-immunologically mediated response or food intolerance. The latter is a general term which can in turn be further divided into different subcategories (see Table 14.1 and Section 14.2.3 ). A third type of adverse food reaction is food aversion, meaning a pure psychological effect evoked by a food. Within the framework of this chapter, no further attention will be paid to this type of reaction. For a better understanding of the mechanisms underlying the first two types of reactions, the basic principles of allergic reactions and of the normal functioning of the digestive tract will be discussed (Sections 14.2.2.1 and 14.2.2.2 respectively). The main causes of food-allergic and food-intolerance reactions are mentioned in Sections 14.2.4.1 and 14.2.4.2, respectively. It is often difficult to discriminate between a food-allergic reaction and a food-intolerance reaction on the basis of clinical data, as the symptoms can be similar (Sections 14.3.1). Further, there is an extensive differential diagnosis, which renders the problem of diagnosis even more difficult (Section 14.3.2). However, it is important to come to the right diagnosis, because only then is it possible to institute an effective treatment (see Section 14.3.3 ). Proper treatment has to start at the root, and therefore it is necessary to know the factors which determine the development of a disease.
