Tree Nuts

Tree nuts include almonds, cashews, walnuts, hazelnuts, pecans, pistachios, brazil nuts, macadamia, and pine nuts. Botanically diverse — almonds are seeds of a stone fruit, cashews and pistachios are in their own family, walnuts and pecans are related — but grouped as a top-eight allergen for labeling because most tree-nut allergic people react to several. The exceptions can be tricky: cashew and pistachio cross-react strongly, walnut and pecan cross-react strongly, but almond and hazelnut are botanically distinct from each other and from cashew/walnut.

For people who tolerate them, tree nuts are nutritionally excellent — protein, fiber, unsaturated fat, magnesium, and a range of antioxidants. Regular nut consumption is consistently associated with lower cardiovascular mortality in long-term observational studies, with small randomized trials supporting better lipid profiles.

Cross-reactivity within tree nuts

Anyone with a confirmed tree-nut allergy should see an allergist for component testing to clarify which specific nuts they need to avoid. Many people are told to avoid all tree nuts unnecessarily; others assume tolerance of one means tolerance of all, which is also risky. Component-resolved diagnostics can identify reactions to specific storage proteins (Ara h 2 for peanut, Cor a 14 for hazelnut, etc.) and refine management.

Distinguishing from peanuts

Peanuts are legumes, not tree nuts. Many people are allergic to one but not the other, though there's some overlap in highly allergic populations. Peanut allergy and tree-nut allergy should be treated as separate diagnoses, evaluated separately. Both warrant epinephrine availability for confirmed cases.