Highly allergenic food introduction and allergy in the CHILD cohort

Published online: October 30, 2019

Early dietary introduction of the most common food allergens among infants has been associated with decreased risk of food allergy for the group of infants who are at the highest risk of food allergy. Further information was needed regarding the importance of early dietary introduction to these highly allergenic foods for infants from the general population, particularly for those at low risk of food allergy.

This study, recently published in The Journal of Allergy and Clinical Immunology: In Practice by Simons et al, used data from the Canadian Healthy Infant Longitudinal Development (CHILD) Study, a cohort of thousands of Canadian infants who were recruited before birth. At least every 6 months, these infants’ parents reported when they introduced highly allergenic foods such as peanut, egg and cow’s milk and if the infants had reactions to these foods at any time. The infants were evaluated by study clinicians for a history of food allergies and conditions related to food allergy, such as moderate or severe eczema in the first year of life. They also had skin prick testing to allergens including peanut, egg and cow’s milk at ages 1 and 3 years.

Associations between age of dietary peanut introduction and development of peanut sensitization (a positive skin prick test) and signs of clinical allergy to peanut were compared in the whole cohort of infants. The analyses were then repeated in subgroups of infants that excluded infants at high risk of peanut allergy because of known risk factors such as moderate or severe eczema in the first year of life and/or reactions to egg plus strong sensitization to egg by age 1 year.

General-population infants introduced to peanut after age 12 months were more likely to have a positive skin prick test and clinical allergy to peanut at age 3 years, even after infants at high risk of peanut allergy were excluded from the analysis. These results demonstrated that infants who are at low risk of peanut allergy may also benefit from early introduction of peanut into their diets. None of the small number of infants introduced to peanut before age 6 months developed peanut sensitization or allergy. Infants who did not have peanut introduced into their diet until after age 18 months had the highest risk of peanut allergy, suggesting that earlier introduction of peanut should still be encouraged, even after age 12 months.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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