Preventing food allergy in infancy and childhood: systematic review of randomised controlled trials.

BACKGROUND:

This systematic review of ways to prevent immediate-onset/IgE-mediated food allergy will inform guidelines by the European Academy of Allergy and Immunology (EAACI).

METHODS:

The GRADE approach was used. Eleven databases were searched from 1946 to October 2019 for randomised controlled trials (and large prospective cohort studies in the case of breastfeeding). The studies included heterogeneous interventions, populations and outcomes so were summarised narratively.

RESULTS:

Forty-six studies examined interventions to reduce the risk of food allergy in infancy (up to one year) or early childhood. The following interventions for pregnant or breastfeeding women and/or infants may have little to no effect on preventing food allergy but the evidence is very uncertain: dietary avoidance of food allergens, vitamin supplements, fish oil, probiotics, prebiotics, synbiotics and emollients. Breastfeeding, hydrolysed formulas and avoiding cow's milk formula may not reduce the risk of cow's milk protein allergy, however temporary supplementation with cow's milk formula in the first week of life may increase the risk of cow's milk allergy. Introducing well-cooked egg, but not pasteurised raw egg, from four to six months probably reduces the risk of hen's egg allergy. Introducing regular peanut consumption into the diet of an infant at increased risk beginning from four to 11 months probably results in a large reduction in peanut allergy in countries with a high prevalence. These conclusions are based on moderate certainty evidence, from single trials in high-income countries.

CONCLUSIONS:

Sixty percent of the included studies were published in the last ten years, but much still remains to be understood about preventing food allergy. In particular, there is a need to validate the potential benefits of early introduction of food allergens in a wider range of populations.