Introduction time of highly allergenic foods to the infant diet in a UK cohort and association with a family history of allergy

Background/Objective: To describe the introduction of highly allergenic foods in a UK population sample, and to determine whether the introduction of highly allergenic foods differed in infants with family history of allergy.

Subjects/Methods: A population birth cohort study recruited eligible pregnant women while they were attending an antenatal ultrasound clinic appointment at a UK city hospital. Parent-reported family history of allergy and infant diet were collected through structured interviews at recruitment and postal questionnaires. Parents reported on their infants' diet and introduction of highly allergenic foods at around 6 months (n = 216) and around 12 months (n = 193), and infant diet around 24 months of age (n = 139).

Results: Most highly allergenic foods were introduced to infants at around 6-9 months. However, nut and egg were introduced much later, and 21% of children had not been exposed to egg and 35% of infants had not been exposed to nuts by 12 months. Family history of allergy did not predict late introduction of any of the highly allergenic foods but infants with a family history of allergy were more likely to have diets that avoided foods due to allergy (most commonly dairy, soya, egg and nuts).

Conclusions: The introduction of egg and nuts was delayed beyond one year of age in a large proportion of infants, and infants with a family history of allergy were more likely to have diets that avoided foods due to allergy. These could be modifiable risk factors for allergy development.