Ingredient decoder
Apple
Apple is a birch-pollen cross-reactive food — its PR-10 Proteins protein resembles the birch allergen closely enough that pollen-allergic people can react to it.
Label check
Raw apple commonly triggers itchy-mouth symptoms in birch-allergic people; cooked apple is usually tolerated because Mal d 1 breaks down with heat.
Allergen family data
| Family | Category | Severity | Mapping |
|---|---|---|---|
| PR-10 Proteins | pollen_food | Usually mild (oral allergy syndrome) | Curated mapping |
Sources: SleuthIt curated dataset
Also appears as
Cross-reactivity
~70% of birch pollen allergics react to raw apple
~50% of birch allergics react to cherry
Birch-celery-mugwort-spice syndrome
Case notes
Apple is one of those ingredients where the word itself isn't the problem — the processing is. Mal d 1, the apple protein in the PR-10 family, is heat-labile: it breaks down when cooked, which is why cooked apple is usually tolerated while raw apple commonly triggers itchy-mouth symptoms in birch-allergic people. An ingredient panel almost never tells you which version you're holding. "Apple" on a label covers both the baked filling and the fresh slice, and that single word does the same work for two very different situations.
Naming adds another layer. On some panels apple appears under its botanical name, Malus domestica, and in allergy testing paperwork you may see Mal d 1 instead — all three refer to the same food. Juice is the trickiest category, since the protein is often destroyed during juice processing but may persist in fresh or minimally processed juice. Two cartons with nearly identical ingredient lists can differ on the one variable that matters.
Apple also sits inside a wider pattern worth recognizing on labels. Its PR-10 protein cross-reacts strongly with the birch allergen Bet v 1 — roughly 70% of birch pollen allergics react to raw apple — and the same family links birch to cherry, where about 50% react, and moderately to celery in what's described as birch-celery-mugwort-spice syndrome. Reactions in this family are usually mild oral allergy syndrome, but the family connection explains why apple shows up on lists alongside foods that look unrelated.
Questions
Apple is a birch-pollen cross-reactive food — its PR-10 Proteins protein resembles the birch allergen closely enough that pollen-allergic people can react to it.