Systematic review of maternal dietary patterns during pregnancy and offspring allergy

Individual studies indicate that maternal diet during pregnancy may be associated with child allergy outcomes. We performed a systematic review to summarize the available data focusing on overall maternal dietary intake rather than single foods and nutrients. Searches included PubMed, OVID Medline, Web of Science, and Embase up to November 28, 2024. Searches were not restricted by geographical location and included studies published in English only. The ROBINS-I Cochrane tool was used to assess risk of bias. Meta-analysis was conducted when ≥2 studies examined the same dietary pattern-outcome-age combination; a fixed- or random-effects model was used based on I². When studies reported multiple effect sizes, a multilevel meta-analysis accounted for within-study clustering. We included 28 papers reporting on 29 diet patterns, indices, or diversity. Diet patterns included healthy and unhealthy diet patterns, healthy and unhealthy diet indices, and healthy and unhealthy diet diversity. Allergy outcomes were atopic dermatitis/eczema, food allergy, allergic rhinitis, asthma, and allergic sensitization/atopy. Only diet diversity during pregnancy showed a modest protective effect against food allergy (OR = 0.95 (0.92-0.99)). A pro-inflammatory diet was linked to increased asthma/wheeze risk in children under 5 (OR = 1.17 (1.04, 1.33)) and (OR = 1.18 (1.04, 1.34)) with high heterogeneity across studies. Modest evidence supports a protective role of diet diversity against food allergy and that pro-inflammatory diets may increase early asthma risk in children. The Maternal diet index is the only index significantly associated with multiple allergy outcomes, and further studies in other cohorts are required.