Existing reports focus on zinc-associated immunity and infection in malnourished children; however, whether zinc also plays an important role in the immune homeostasis of the non-zinc-deficient population remained unknown. This study aimed to investigate the association between zinc status and toll-like receptor (TLR)-related innate immunity and infectious outcome in well-nourished children. A total of 961 blood samples were collected from 1 through 5 years of age. Serum zinc was analyzed, and mononuclear cells isolated to assess TNF-α, IL-6, and IL-10 production by ELISA after stimulation with TLR ligands. Childhood infections were analyzed as binary outcomes with logistic regression. The prevalence of zinc deficiency was 1.4–9.6% throughout the first 5 years. There was significant association between zinc and TLR-stimulated cytokine responses. Higher serum zinc was associated with decreased risk of ever having pneumonia (aOR: 0.94; 95% CI: 0.90, 0.99) at 3 years, and enterocolitis (aOR: 0.96; 95% CI: 0.93, 0.99) at 5 years. Serum zinc was lower in children who have had pneumonia before 3 years of age (72.6 ± 9 vs. 81.9 ± 13 μg/dL), and enterocolitis before 5 years (89.3 ± 12 vs. 95.5 ± 13 μg/dL). We emphasize the importance of maintaining optimal serum zinc in the young population.

This study investigated whether the introduction of allergenic foods in infancy is associated with atopic dermatitis (AD) in early childhood. Information regarding parental allergic histories, the introduction of six possible allergenic foods (fruits, egg white, egg yolk, fish, shellfish, and peanuts), and physician-diagnosed AD was obtained using age-specific questionnaires (0–2 years). Immunoglobulin E, specific to 20 food allergens, was also quantified at 12 months of age. Logistic regression analyses were used to determine the association between individual food introduction and the outcomes of food sensitization and AD. We found AD development by 2 years of age was significantly related to a parental history of allergy (adjusted odds ratio (aOR) = 1.29) and not being introduced to egg white and yolk during infancy (aORs = 2.27 and 1.97, respectively). Stratified analyses revealed that the introduction of both egg white and yolk was negatively associated with AD by 2 years of age, especially for those children where both parents had allergic diseases (aOR = 0.10). In summary, the introduction of egg white and yolk to an infant’s diet may be a modifiable factor in reducing the risk of physician-diagnosed AD by 2 years of age, which may be particularly important for infants where both parents have allergies.