Introduction of Complementary Foods to Infants.

While earlier food allergy prevention strategies implemented avoidance of allergenic foods in infancy, the current paradigm is shifting from avoidance to controlled exposure. This review focuses on the outcome of recent randomized controlled trials, which have examined the early introduction of allergenic foods for allergy prevention, and discusses the implementation of results in clinical practice. In infants at high risk of allergic disease, there is now direct evidence that regular early peanut consumption will reduce the prevalence of peanut allergy, compared to avoidance. Many international infant feeding guidelines already recommend complementary foods, including allergenic foods, to be introduced from 4 to 6 months of age irrespective of family history risk. Interim guidelines from 10 International Pediatric Allergy Associations state that healthcare providers should recommend the introduction of peanut-containing products into the diets of infants at high risk of allergic disease in countries where peanut allergy is prevalent. Direct translation of the results obtained from a cohort of high-risk infants to the general population has proved difficult, and issues regarding feasibility, safety, and cost-effectiveness have been raised. Five randomized placebo-controlled trials have assessed the effects of early egg exposure in infancy with varying results. In a recent comprehensive meta-analysis, there was moderate-certainty evidence that early versus late introduction of egg was associated with a reduced egg allergy risk. Although promising, optimal timing, doses, and if the feeding regimen should be stratified according to infant allergy risk remain to be determined. The single study that assessed introduction of multiple foods from 3 months whilst breastfeeding compared with exclusive breastfeeding until 6 months of age showed no reduction in food allergy prevalence. Future research should aim at optimizing infant feeding regimens and support a tolerogenic gastrointestinal microenvironment during the period of food allergen introduction.