The antioxidant capacity and the inflammatory potential of diet during pregnancy may represent a prevention opportunity for allergic and respiratory diseases. We aimed to investigate the associations between the antioxidant and the inflammatory potential of maternal diet in the last 3 months of pregnancy with allergic and respiratory diseases in children. Analyses were performed on 9679 mother–child pairs from the ELFE birth cohort. The dietary total antioxidant capacity (DTAC), without coffee, was estimated with the Trolox equivalent antioxidant capacity (TEAC), the total radical trapping antioxidant parameter (TRAP) and the ferric reducing-antioxidant power (FRAP). The inflammatory potential of the maternal diet was assessed by the energy-adjusted dietary inflammatory index (E-DII). Allergic and respiratory diseases in children up to 5·5 years were considered jointly through five allergic and respiratory multimorbidity clusters (‘asymptomatic’ - reference, ‘early wheeze without asthma’, ‘asthma only’, ‘allergies without asthma’ and ‘multi-allergic’). Multinomial logistic regressions were performed and adjusted for main confounders. A diet with a higher antioxidant potential was associated with a lower risk of belonging to the ‘early wheeze without asthma’ cluster (aOR (95 % CI) = 0·95 (0·90, 0·99) per sd of TEAC score). A higher E-DII was associated with a higher risk of belonging to the ‘asthma only’ cluster (aOR (95 % CI) = 1·09 (1·00, 1·19) per sd). No association was found with the ‘allergies without asthma’ or ‘multi-allergic’ clusters. An antioxidant-rich diet during pregnancy was associated with better respiratory health, while a pro-inflammatory diet was associated with poorer respiratory health in children up to 5·5 years, though the associations were weak.< Leer menos