Fruits and vegetables

Introduction

Vegetables and fruits are staple foods in diets worldwide although the types of vegetables and fruits consumed vary widely. It is therefore not surprising that considerable geographical variations exist in respect of adverse reactions to specific fruits and vegetables. Vegetables, and more particularly fruit, may cause adverse reactions that are either IgE-mediated which most often have their onset after the first few years of life (in contrast to many other foods), or occur via other mechanisms, typically in early childhood. Key epidemiological studies are shown in Table 10.8.

Table 10.7 Epidemiology of adverse food reactions to wheat - key studies

Author, date Type of study

Country

No. of subjects Point prevalence

Cumulative incidence

Definition

Young et al. 1994 Population based, cross-sectional

Dean 1997

Population based, birth cohort

1996

sectional

Kulig et al. 1999 Population based, birth cohort

Kajosaari 1982 Population based, cross-sectional

Bock 1987

Population based, birth cohort

UK UK

Bjornsson et al. Population-based, cross- Sweden

Germany

Finland

18 880 1218

1397

4082

History History

Sp IgE ± history Sp IgE

Open challenge at home

Open history ± double-blinded food challenges

Table 10.8 Epidemiology of adverse food reactions to fruit and vegetables - key studies

Author, date

Type of study

Country

No. of subjects Point prevalence

Cumulative incidence

Comments

Foucard 1991 Cross-sectional, medical Sweden students

Young et al. 1994 Population based, cross- UK sectional

Niestijl Jansen et Population based, cross-al. 1994 sectional

Saarinen and Kajosaari 1980

Population based, birth cohort

Varjonen et al. Atopic population, cross-1992 sectional

Saarinen and Kajosaari 1980

Kajosaari 1982

Bock 1987

Population based, birth cohort

Population based, cross-sectional

Population based, birth cohort

Holland

Finland Finland

Finland Finland

1050 18 880

1483

145 416

145 802

7% apple/related fruits

3.5% citrus 1.2-1.3% tomatoes 1.0% non-citrus 0.5% vegetables at > 6 months old

2.2% vegetables 1.6% fruit at 18-70y

6.9% apple 3.8% carrot 1.4% celery 1.2% paprika 0.2% orange at 15-16y

Citrus fruits 5% at 1y 2% at 6y

Citrus fruits 13.1% to 3y

History History

History History

History and SPT

Citrus fruits 3.4% to 3y

Fruits and fruit juices 12% to 3y

Open challenge at home

Open challenge at home

Open history ± double-blinded food challenges

Prevalence and natural history

In the young child, fruits and fruit juices may cause minor gastro-intestinal reactions. Fruits and vegetables, particularly tomatoes, strawberry and citrus fruits also cause perioral rashes, usually eczema and urticaria, in early childhood. If one includes these minor non-IgE mediated skin and gastro-intestinal symptoms, fruits and fruit juices were the foods most commonly causing adverse reactions in one study with a cumulative incidence of 12% in children less than three years of age, with 58% of reactions occurring to orange juice, tomato juice and apple (Bock 1987). Other studies suggest a cumulative incidence of adverse reactions to citrus fruits of around 3-5% in the first three years of life (Saarinen and Kajosaari 1980, Kajosaari 1982), with a higher rate of 13% if the definition is based on history rather than food challenge (Saarinen and Kajosaari 1980).

In contrast to the minor reactions of early childhood, IgE-mediated reactions occur later, so that up to 75% of IgE reactions to fruits and vegetables have their onset after two years of age (Crespo et al. 1995). In an allergy clinic based study, fruits and vegetables were responsible for the vast majority of IgE-mediated food allergy presenting after the age of ten years (Kivity et al. 1994). Many of these later childhood reactions occur in a subgroup of children with pollen sensitisation resulting in cross-reactivity to a range of fruits. This food allergy presents as a contact allergy with oral symptoms, known as the oral allergy syndrome, and occurs mainly with raw fruit or vegetables. The prevalence of allergy to different fruits and vegetables varies with the type and amount of pollen present, which determines the cross-reacting fruits and vegetables. Thus in Scandinavia, with its high levels of birch pollen, there is a high prevalence of apple allergy (Foucard 1991), whereas in Japan where there is more Japanese cedar, the allergy is mainly to melon and kiwi (Arai et al. 1998).

Regarding the natural history of adverse reactions to fruits and vegetables, clinical reactivity is short-lived in those children with onset in early childhood. In one study, tolerance to fruits and fruit juices was achieved after a mean of 15 months (range 3-34 months, median 13 months) (Bock 1987). The natural history data for the later onset predominantly IgE-mediated reactions are not well defined, but are certainly of longer duration.

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