Nuts For Babies Study: protocol for a randomised controlled trial in Australia investigating if the risk of developing peanut and cashew nut allergies during infancy can be reduced by a high peanut and cashew nut maternal diet for the first 6months of lactation

Introduction The predisposition to food allergy development and the induction of allergen-specific immune responses appears to be initiated early in infancy. Early exposure to food allergens, such as peanut and cashew nut, via human milk is likely important in initiating oral tolerance and reducing risk of food allergy development. This trial aims to determine if the risk of developing peanut and cashew nut allergy during infancy can be reduced by a high peanut and cashew nut maternal diet during lactation. Methods and analysis This is a multisite, parallel, two-arm (1:1 allocation), single-blinded (outcome assessors, statistical analyst and investigators), randomised controlled trial. Target sample size is 4412 participants (2206 per group). Women (aged 18–50 years) with a singleton pregnancy, who are planning to breastfeed and do not have peanut and/or cashew nut allergies are eligible to participate. After obtaining written informed consent, participants are randomised to either a high peanut and cashew nut diet (at least 60 peanuts and 40 cashew nuts per week) or a low peanut and cashew nut diet (no more than 20 peanuts and 12 cashew nuts per week). Participants are asked to follow their allocated diet from birth to 6 months postnatal. Individual lactation consultant advice and support is provided as required. The study’s primary outcome is food challenge proven IgE-mediated peanut and/or cashew nut allergy during infancy (0–18 months). Key secondary outcomes include infant sensitisation to peanut and/or cashew nut. Analyses will be performed on an intention-to-treat basis according to a prespecified statistical analysis plan. Ethics and dissemination Ethical approval has been granted from the Western Australian Child and Adolescent Health Service Human Research Ethics Committee (approval number RGS0000006685). Trial results will be presented at scientific conferences and published in peer-reviewed journals.