Hazelnut biomarkers represent proteins from the hazelnut tree, Corylus avellana, including seed storage proteins (legumins and vicilins), lipid transfer proteins (LTPs), profilins, and PR‑10 family proteins such as Bet v 1 homologs. Biochemically these are plant-derived storage and defense proteins that supply nutrients to the seed and protect the plant from stressors. Historically, specific hazelnut proteins were identified as targets of immune recognition when people reported reactions after eating tree nuts or after pollen exposure; researchers mapped individual components (e.g., Cor a 1, Cor a 8, Cor a 9, Cor a 14) to distinguish patterns of immune reactivity. Understanding which protein classes are recognized can clarify whether responses are driven by heat‑stable storage proteins, cross‑reactive pollen homologs, or labile profilins and LTPs.

Elevated IgA or IgG signals to hazelnut proteins typically indicate prior immune exposure and recognition of one or more hazelnut protein classes; patterns can suggest whether mucosal (IgA) or systemic (IgG) pathways are more active. Higher responses may cluster with responses to other tree nuts or with pollen homologs, signaling possible cross‑reactivity rather than unique sensitivity. Low or absent signals suggest limited immune recognition, recent low exposure, or tolerance in the measured compartments. Interpretation is most informative when viewed with the full Food Zoomer profile, including other nut, seed, and pollen-related markers, to distinguish isolated reactivity from broader immune patterns.

Hazelnut is included to evaluate immune recognition of common tree‑nut proteins and related plant proteins. The marker set assesses whether mucosal or systemic antibody patterns target storage proteins, LTPs, or pollen‑homolog proteins, helping providers map clusters of reactivity and tailor dietary and testing decisions based on individual immune patterns.