A new study has provided the most comprehensive data to date on walnut allergy thresholds, addressing a critical gap in global food allergen risk assessment.
Researchers analysed published results of 415 oral food challenges (OFCs) in walnut-allergic children between 2014 and 2023. The estimated eliciting doses (ED01 and ED05)—the smallest amounts of walnut protein that trigger reactions in 1% and 5% of allergic individuals—were found to be 0.8 mg and 3.8 mg, respectively, for discrete dosing.
The study also found that younger age, co-allergy to pecan, and undergoing oral immunotherapy were linked to lower reaction thresholds. Importantly, no objective reactions occurred at doses below 1 mg in safe-dose OFCs, suggesting a potential baseline for future labelling discussions.
Despite walnut being a major global allergen, limited data on reaction thresholds has hindered the development of evidence-based labelling standards. This uncertainty often leads to overuse of precautionary allergen labelling (PAL), which can reduce consumer trust and quality of life for allergy sufferers. The World Health Organization and Codex Alimentarius have emphasised the need for evidence-based threshold data to support global allergen risk management frameworks.
Reference: Nachshon, et al., 2025. Walnut threshold dose distribution and safe dose in allergic patients (Nut CRACKER Study). Journal of Allergy and Clinical Immunology: In Practice. DOI: 10.1016/j.jaip.2025.05.041
