sign101

3.1.2 FOOD ALLERGEN AvOIDANCE
Sensitisation to foods, particularly eggs, frequently precedes the development of aeroallergy
and subsequent asthma. 135 Food allergen avoidance in pregnancy and postnatally has not been
shown to prevent the later development of asthma. 136 Allergen avoidance during pregnancy
may adversely affect maternal, and perhaps fetal, nutrition. 137 High-dose food allergen exposure
during pregnancy may reduce subsequent sensitisation rates by inducing tolerance. 138
B In the absence of any evidence of benefit and given the potential for adverse effects,
maternal food allergen avoidance during pregnancy and lactation is not recommended
as a strategy for preventing childhood asthma.
3.1.3 BREAST FEEDING
A systematic review of observational studies on the allergy preventive effects of breast feeding
indicates that it is effective for all infants irrespective of allergic heredity. The preventive effect
is more pronounced in high-risk infants provided they are breast fed for at least four months. 139
However, not all studies have demonstrated benefit and in a large birth cohort there was no
protective effect against atopy and asthma and maybe even an increase in risk. 140
Observational studies have the potential to be confounded by, for example, higher rates of breast
feeding in atopic families, and taking this into account, the weight of evidence is in favour of
breast feeding as a preventive strategy.
C Breast feeding should be encouraged for its many benefits, and as it may also have a
potential protective effect in relation to early asthma.
3.1.4 MODIFIED INFANT MILK FORMULAE
Trials of modified milk formulae have not included sufficiently long follow up to establish
whether there is any impact on asthma. A Cochrane review identified inconsistencies in findings
and methodological concerns amongst studies, which mean that hydrolysed formulae cannot
currently be recommended as part of an asthma prevention strategy. 141 A review of the use of
soy formulae found no significant effect on asthma or any other allergic disease. 142
In the absence of any evidence of benefit from the use of modified infant milk formulae it is
not possible to recommend it as a strategy for preventing childhood asthma.
3.1.5 WEANING
3 non-PhArMAColoGiCAl MAnAGeMent
There are conflicting data on the association between early introduction of allergenic foods into
the infant diet and the subsequent development of allergy and atopic eczema. No evidence was
identified in relation to asthma. 143 In one study late introduction of egg was associated with a
non-significant increase in pre-school wheezing. 144
in the absence of evidence on outcomes in relation to asthma no recommendations on
modified weaning can be made.
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