Multiple systematic reviews examine the introduction of foods in relation to individual health outcomes, but the balance of harms and benefits has not been overviewed systematically.
We aimed to perform an overview of systematic reviews on age of introduction of complementary and allergenic foods to the infant diet and long and short-term health outcomes.
We searched Medline, Embase, Cochrane, and PubMed (July 25, 2022).
Included systematic reviews examining the introduction of complementary or allergenic foods before age 1. Outcomes included allergic, autoimmune, and inflammatory diseases, neurodevelopment, nutrition, and weight.
Extraction and quality assessment were performed in duplicate (A Measurement Tool to Assess Systematic Reviews) and strength of evidence was assessed.
We screened 4015 articles and included 32 systematic reviews. There was moderate evidence that peanut and egg should be introduced from 4 to 11 months to prevent food allergy (6 of 10 reviews). Complementary food introduction was not associated with food allergy. Moderate certainty evidence suggested age of complementary food introduction was not associated with eczema. Age at introduction of gluten was not associated with celiac disease (high certainty evidence; 3 of 4 reviews). Low certainty evidence indicated that introducing solids before 4 months may increase the risk of childhood obesity, but not growth. There was insufficient evidence regarding an association between any food introduction and bone health, gastrointestinal diseases, autoimmune disorders, asthma, or allergic rhinitis.
Gray literature was not included.
Current evidence supports introducing complementary foods around 6 months and allergenic foods before 11 months.