A few studies have shown a protective effect of high food diversity in the first year on food allergies and asthma. Results are more controversial for atopic dermatitis and allergic rhinitis and the age at complementary food (CF) introduction did not appear to be strongly associated with allergic diseases.

Our aims were to explore the association between allergic diseases in childhood and 1/the age at CFI, 2/food diversity before 1 year of age 3/late introduction of some food allergens.

The analyses were based on 8931 children from the French nationwide ELFE cohort without allergic symptoms at age 2 months. Feeding practices were collected monthly from 3 to 10 months of age. The age at CF introduction was calculated, as well as a diversity score at 3, 4, 6 and 8 months. The number of major food allergens (eggs, fish, gluten and milk) not introduced at age 10 months was calculated. Allergic-related health events (itchy rash, wheezing, asthma, food allergy, allergic rhinitis or conjunctivitis) were reported by parents at 2 months, 1, 2, 3.5 and 5.5 years. Associations between CF characteristics and risk of allergic diseases were assessed by logistic regressions adjusted for confounding factors including family history of allergy and breastfeeding duration.

Compared to the recommended CF introduction age (4–6 months), a late introduction of CFs (>6 months) was related to a higher risk of food allergy between 1 and 5.5 years (OR[95% CI]: 1.35[1.07;1.70]). A high diversity score at 8 months was related to a lower risk of allergic diseases, in particular asthma (OR[95% CI]: 0.96[0.93;0.99]) and food allergies (OR[95% CI]: 0.94[0.89;0.99]). The higher the number of allergenic foods not introduced at 10 months, the higher the risk of food allergy (OR[95% CI]: 3.58[2.18;5.87]) and rhinoconjunctivitis (OR[95% CI]: 1.61[1.10;2.36]). Weighted analysis, accounting for selection and attrition bias, gave similar results.

The findings from this large nationwide birth cohort underlined the need of promoting high food diversity during complementary feeding, in the prevention of allergic diseases, as mentioned in the new nutritional guidelines.