Preventing Food Allergy by Early Food Introduction: East Meets West With the Lack Dual-Allergen Exposure Theory.

Food allergy (FA) is a growing global health concern with prevalence varying by region, influenced by genetic, environmental, and cultural factors. Eczema represents the strongest early-life risk factor, which supporting the Lack dual-allergen exposure hypothesis in which disrupted skin barriers facilitate sensitization, whereas timely oral exposure promotes tolerance. Over recent decades, prevention strategies have shifted from allergen avoidance to early introduction, particularly after the Learning Early About Peanut Allergy study. Although early egg introduction has been associated with a reduced risk of egg allergy in some studies, others have reported no significant effect. In contrast, early peanut introduction has strong preventive effects in Western countries with high peanut allergy prevalence, but it appears less impactful in Japan, where peanut consumption and prevalence are low. The role of early cow's milk introduction remains inconclusive, although recent Japanese data suggest possible benefit from small daily intake. Effective eczema management, including proactive anti-inflammatory therapy, may be crucial, because moisturizers alone are insufficient for FA prevention. Sustained and regular allergen intake after early introduction is likely to support long-term tolerance further. Prevention strategies must also account for cultural feeding practices, family dietary habits, and regional epidemiology, because these factors shape feasibility and public health relevance. Supporting a smooth transition to family foods, such as encouraging infants to share family meals without unnecessary restrictions, may help sustain tolerance and promote healthy eating patterns. Collaboration between Eastern and Western medical communities will be essential to harmonize evidence with cultural practices and develop effective, personalized FA prevention strategies worldwide.