D2.307 - Parental and Healthcare Professional Experiences of Food Allergen Introduction during Complementary Feeding: A Behavioural Theory–Informed Systematic Review

IgE-mediated food allergy places a substantial burden on individuals, families, and healthcare systems, with global prevalence rates appearing to have increased in recent decades. Evidence from randomised controlled trials (RCTs) shows early, regular introduction of common food allergens can reduce food allergy risk. However, optimal timing, quantity, and frequency of food consumption remain uncertain. Adherence rates in RCTs introducing multiple foods have been sub-optimal. Few studies have explored parental and healthcare professional (HCP) experiences and beliefs, limiting effective implementation. This systematic review examines those perspectives and applies a theory-informed behavioural analysis to identify key barriers and target behaviours influencing early food introduction.

A systematic search of seven databases was conducted. Screening and appraisal were conducted using the Critical Appraisal Skills Programme (CASP) and Mixed Methods Appraisal Tool (MMAT). Qualitative and quantitative findings were analysed concurrently and  synthesised using integrated thematic synthesis. Barriers to early allergen introduction were mapped to the Capability, Opportunity, Motivation-Behaviour (COM-B) model and Theoretical Domains Framework, to identify target behaviours and potential intervention strategies.

Of 13,936 records identified, 25 studies (six qualitative,19 quantitative) were included. Four themes representing barriers and enablers for HCPs and parents were identified: 1. Practical barriers to introducing the common food allergens, 2. Perceived fear and risk of allergic reactions and safety, 3. Navigating and making sense of food allergy prevention information, (particularly conflicting advice for parents)  4. Food allergy prevention advice, guidance awareness, interpretation and implementation. Consistent communication and advice, with family support, were identified as important for implementing this food allergy prevention strategy. Approaches should be realistic, family-centred, culturally responsive, and feasible. Early support and advice from HCPs is essential, alongside appropriate training and tools to deliver confident, evidence-based guidance.

The synthesised evidence indicates effective food allergy prevention is complex and extends beyond timing, amount, and frequency of allergen introduction. Embedding prevention within early complementary feeding advice, delivered by trusted HCPs through multiple accessible formats (digital, written, face-to-face), may improve equitable access to information. Approaches should be adapted for local contexts to enable sustained allergen exposure and support the translation of evidence into clinical practice.