Introduction

Plant-based diets (PBDs) represent a diverse spectrum of dietary patterns prioritizing plant-derived foods with the optional inclusion of small amounts of animal products. PBDs are highly encouraged for human health and environmental sustainability.1,2 The EAT-Lancet Commission advocates PBDs for their potential health benefits, including reduced risk of non-communicable diseases.3,4 The European Food Safety Authority (EFSA) provides further scientific guidance to this.5 PBDs encompass various dietary approaches such as vegetarian, and flexitarian diets (Supplemental Table 1).2 A vegan diet, by contrast, strictly excludes all foods wholly or partially derived from animals.6 An increasing proportion of the Western population identifies as flexitarian, meaning individuals who predominantly follow a PBD while occasionally consuming meat and animal-derived products.7,8 A 2023 survey across Europe reported that 1–5% of the adult population identified as vegan, 4–6% as vegetarians and 16–40% as flexitarian. Additionally, 53% of European adults plan to increase their legumes consumption while 40% intend to opt for more plant-based alternatives.7 In parallel with changing consumer dietary habits, the European market has responded with a marked increase in the availability of plant-based food products. Based on new product launches tracked in a commercial food database and reported by an industry association, launches containing plant-based proteins increased between 2012 and 2017 (average annual growth, 13.5%).9 Although wheat and soy dominated the launches in 2017 (84%), the market progressively diversified with pea protein emerging as a significant contributor, increasing from 0.9% to 12% of launches between 2007 and 2017 respectively.9 This growth has continued, with global alternative-protein product launches rising at a 10% annual rate between 2020 and 2024.10

This transition may have important implications for immunoglobulin E (IgE)-mediated food allergy (FA), the most common immunological form, which carries a risk of anaphylaxis.11 Whether exposure to novel or increasingly consumed plant-derived proteins is associated with changes in allergic sensitization and clinical allergy profiles remains unknown.12, 13, 14 The most common elicitors of food-induced anaphylaxis (FIA) in children include peanut, tree nuts (cashew, hazelnut), cow's milk, and hen's egg, whereas wheat, shellfish, peanut, hazelnut, and soy are frequently implicated in adults.15, 16, 17, 18, 19, 20, 21 Despite the growing adoption of PBDs, data on their coexistence with FA remain limited. This represents a clinically relevant gap.22 PBDs rely on a group of protein-rich plants, including legumes, cereals, nuts and seeds to meet the recommended protein intake, many of which are recognized food allergens.23, 24, 25, 26 Individuals with allergies to plant proteins may face substantial challenges when attempting to reduce or eliminate animal-derived products.27 Moreover, there is a lack of clear, evidence-based dietary guidance for food-allergic individuals seeking to adopt more PBDs. Overall, the relationship between PBDs and FA remains complex and is challenging to comprehensively address due to emerging allergens, cross-reactivities, and limited population-level data. A pragmatic approach is to focus on individuals with established FA, as identified through food anaphylaxis registries. Such registries record reactions by culprit allergen, irrespective of dietary patterns; cases therefore reflect real-world exposure to these allergens regardless of individual diet.

This study aims to characterize the clinical phenotypes of FIA attributed to plant allergens relevant to PBDs in adolescents and adults, using data from a large cohort of FIA cases reported to the Allergy-Vigilance Network (AVN) over a 23-year period (2002–2024). These age groups were included because dietary habits, including PBD adoption, are typically established from adolescence onwards. Characterizing these phenotypes may help guide the counseling of food-allergic or atopic patients who wish to adopt a PBD.