Exposure to environmental microbes (small living things like bacteria) plays a role in both mother and child's gut microbiome (good bacteria inside you), immune system development, and susceptibility to food allergy.
The role of chemicals is less understood. A common source of early life microbial exposure are pacifiers, also known as dummies or soothers.
Cleaning Methods and Food Allergies
While previous research has demonstrated a potential benefit of shared microbial exposure through parents sucking their infants' pacifiers for allergic diseases, no previous work has investigated pacifier cleaning methods (sanitisation) in association with challenge-proven food allergy.
In a longitudinal cohort study recently published in The Journal of Allergy and Clinical Immunology (JACI), Victoria X. Soriano and colleagues sought to find out whether infant pacifier use, considering sanitization methods, in the first year of life alters the risk of food allergy by age 1 year.
The birth cohort recruited pregnant mothers in the Barwon region of Australia with 894 families and followed up when infants turned 1 year. Parents were asked about pacifier use and pacifier sanitization (defined as the joint exposure of a pacifier and cleaning methods) when their infant was 1, 6, and 12 months old.
Antiseptics a Risk Factor
The gold standard oral food challenge was used to diagnose food allergy in children at 12 months.
Pacifiers cleaned with antiseptic agents at 6 months were a risk factor for food allergy in 1-year-old infants. Other cleaning methods including boiling did not affect risk of food allergy. However, among pacifier users, antiseptic cleaning at 6 months increased the risk of children developing a food allergy, compared to no antiseptic use.
Furthermore, using antiseptic cleaning methods persistently and repeatedly over the first 6 months was also associated with a higher food allergy risk than using them during only one time interval.
This longitudinal study is the first report of early life exposure to pacifiers cleaned with antiseptics, but not other cleaning methods, increasing a child's risk of food allergy. Future studies should investigate underlying biological pathways.
Source: Soriano VX, et al. "Infant pacifier sanitization and risk of challenge-proven food allergy: A cohort study." The Journal of Allergy and Clinical Immunology 1 May 2021