This is not a diagnosis. Being sensitised to a pollen does not mean you will react to these foods, and only an allergist's tests can tell what applies to you. If a food makes your mouth itch or swell, mention it at your next appointment.
If you have trouble breathing, swelling of the throat or tongue, or feel faint, call emergency services (999 in the UK, 112 in Ireland, 911 in the US).
Which foods are linked to each pollen
"Best documented" means the European Academy of Allergy and Clinical Immunology (EAACI) guide or several sources name the food; "also reported", that at least one reliable source does. Neither says how many people react: no source gives that figure food by food.
Birch
What causes it. Birch's Bet v 1 protein (a PR-10) closely resembles proteins in many fruits, nuts and vegetables. Less often, profilin (Bet v 2) is involved.
Best documented
- Apple
- Hazelnut
- Carrot
- Celery
- Cherry
- Pear
- Peach
- Soy (especially soy drinks and protein powder)
Also reported
- Almond
- Kiwi
- Plum
- Apricot
- Strawberry
- Peanut
- Walnut
Does cooking help? PR-10 is usually broken down by cooking, so cooked fruit such as apple compote is usually tolerated. There are exceptions: roasted hazelnuts and cooked celery can still cause symptoms, and soy drinks or soy protein powder can cause severe reactions. Any reaction to nuts or soy should be checked by an allergist.
One figure. Around 70% of people with birch pollen allergy also react to some plant foods, according to the EAACI guide. The American academy AAAAI puts it at 50-75% of adults.
Sources: EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023); Oral Allergy Syndrome (OAS) or Pollen Food Syndrome (American Academy of Allergy, Asthma & Immunology, 2026); Pollen Food Allergy Syndrome (American College of Allergy, Asthma & Immunology, 2019).
Birch pollen allergy: season and symptoms
Alder
What causes it. Alder's Aln g 1 belongs to the same family (PR-10) as birch's main protein, so it can trigger the same fruit and nut reactions.
Best documented
Also reported
- Cherry
- Pear
- Peach
- Hazelnut
- Almond
- Carrot
- Celery
Does cooking help? Cooking breaks PR-10 down, so stewed, baked or tinned fruit is usually tolerated. Nuts, celery and soy can still react after processing, so get these checked by an allergist.
One figure. In a region of Japan with no birch pollen, oral allergy syndrome was linked to sensitisation to alder and birch.
Sources: EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023); Epidemiological study of oral allergy syndrome in birch pollen dispersal-free regions (Osawa et al.) (Allergology International, 2020); Oral Allergy Syndrome (Pollen Food Syndrome) factsheet (Allergy UK, 2021).
Alder pollen allergy: season and symptoms
Grass
What causes it. Grass profilin (Phl p 12), a protein shared by many plants. It usually causes mild mouth itching with the raw food.
Best documented
- Tomato
- Melon
- Watermelon
- Citrus (orange and others)
Also reported
- Peach
- Kiwi
- Banana
- Pineapple
- Courgette (zucchini)
- Cucumber
- Celery
Does cooking help? Profilin is broken down by heat and digestion, so tomato sauce or tinned fruit is usually tolerated. That does not hold if the reaction is caused by an LTP, common with peach in Spain and Italy, which survives cooking.
Sources: EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023); Profilin sensitization detected in the office by skin prick test (Asero et al.) (Clinical & Experimental Allergy, 2008); Pollen Food Allergy Syndrome (American College of Allergy, Asthma & Immunology, 2019).
Grass pollen allergy: season and symptoms
Olive
What causes it. The olive protein linked to food is its LTP (Ole e 7), not its profilin. LTPs survive cooking and digestion.
Best documented
Also reported
Does cooking help? LTP sits mainly in the skin, so peeling fruit lowers exposure without removing it, and it survives cooking, so cooked or tinned fruit is not a safe test. Olive-related reactions to fruit can be severe: if you have had more than mouth itching, see an allergist.
One figure. In a Spanish series of 134 patients allergic to olive pollen, 40 (30%) reported reactions to plant foods, and 19 of them had had anaphylaxis.
Sources: An allergen from Olea europaea pollen (Ole e 7) is associated with plant-derived food anaphylaxis (Florido López et al.) (Allergy, 2002); Non-specific lipid-transfer proteins: allergen structure and function, cross-reactivity, sensitization, and epidemiology (Skypala et al.) (Clinical and Translational Allergy, 2021); Cross-reactivity between aeroallergens and food allergens (Popescu) (World Journal of Methodology, 2015).
Mugwort
What causes it. There is no single protein. Mugwort's LTP (Art v 3) explains the link with peach and mustard. For celery and spices the cause is still unidentified: profilin (Art v 4), the defensin Art v 1 and other glycoproteins are candidates.
Best documented
Also reported
- Fennel
- Parsley
- Aniseed
- Cumin and coriander
- Chamomile (tea)
- Sunflower seeds
- Bell pepper
Does cooking help? Cooking does not reliably help. Celery can still cause reactions cooked or as a dried spice, and the LTP in peach and mustard survives heat. Chamomile tea has caused severe reactions even though it is made with boiling water. If you have reacted to celery, spices, mustard or chamomile, see an allergist.
One figure. The most severe celery reactions occur in people sensitised to mugwort, according to the EAACI guide. In a Chinese study of 148 mugwort-allergic patients, 72% had a food allergy, mostly linked to LTP.
Sources: EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023); Cross-reactivity between aeroallergens and food allergens (Popescu) (World Journal of Methodology, 2015); Influence of food processing on the allergenicity of celery: DBPCFC with celery spice and cooked celery (Ballmer-Weber et al.) (Allergy, 2002); Mugwort pollen-related food allergy: lipid transfer protein sensitization and correlation with the severity of allergic reactions (Gao et al.) (Allergy, Asthma & Immunology Research, 2019).
Ragweed
What causes it. Mainly ragweed profilin (Amb a 8). Its LTP (Amb a 6) is a second candidate.
Best documented
Also reported
- Courgette (zucchini)
- Cucumber
- Sunflower seeds
Does cooking help? Profilin is destroyed by heat, so cooked courgette is usually tolerated. Melon, watermelon and banana are eaten raw, so the practical advice is to avoid the raw fruit that gives you symptoms.
One figure. Antibodies are not the same as symptoms: in one study, only 6 of 26 patients with IgE antibodies to watermelon had symptoms when they ate it.
Sources: Watermelon and ragweed share allergens (Enberg et al.) (Journal of Allergy and Clinical Immunology, 1987); Melon and banana sensitivity coincident with ragweed pollinosis (Anderson et al.) (Journal of Allergy, 1970); Cross-reactivity between aeroallergens and food allergens (Popescu) (World Journal of Methodology, 2015).
Ragweed pollen allergy: season and symptoms
Cypress
What causes it. A gibberellin-regulated protein in cypress pollen (Cup s 7), which cross-reacts with its counterparts in peach (Pru p 7) and orange (Cit s 7). It is not profilin.
Best documented
- Peach
- Citrus (orange and others)
Also reported
Does cooking help? This protein resists heat and digestion and is found in both pulp and peel, so neither cooking nor peeling prevents a reaction. It can be severe (swelling of the face or eyelids, throat tightness, anaphylaxis), sometimes only together with exercise or anti-inflammatory painkillers. If you react to peach or citrus, see an allergist.
One figure. In a French study of 198 peach-allergic patients, 62% were sensitised to Pru p 7, the cypress-related peach protein, which was linked to cypress pollen exposure and to more severe reactions.
Sources: EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023); Pru p 7 sensitization is a predominant cause of severe, cypress pollen-associated peach allergy (Klingebiel et al.) (Clinical & Experimental Allergy, 2019); Gibberellin-regulated proteins: emergent allergens (Iizuka et al.) (Frontiers in Allergy, 2022).
Plane tree
What causes it. Plane tree's LTP (Pla a 3). Neither its profilin nor its Pla a 1 protein explains the food reactions.
Also reported
- Hazelnut
- Peach
- Apple
- Peanut
- Maize (corn)
- Chickpea
- Lettuce
Does cooking help? LTP is not destroyed by cooking or digestion, and reactions to nuts, peanuts, peach or maize can be severe. Cooking does not make these foods safe: if you react to any of them, see an allergist.
One figure. In a Barcelona study, 61 of 720 pollen-allergic patients were sensitised to plane tree pollen, and 32 of them (52%) had a plant-food allergy, most often to hazelnut, peach, apple, peanut, maize, chickpea and lettuce.
Sources: Platanus acerifolia pollinosis and food allergy (Enrique et al.) (Allergy, 2002); Non-specific lipid-transfer proteins: allergen structure and function, cross-reactivity, sensitization, and epidemiology (Skypala et al.) (Clinical and Translational Allergy, 2021); IgE reactivity to profilin in Platanus acerifolia pollen-sensitized subjects with plant-derived food allergy (Enrique et al.) (Journal of Investigational Allergology and Clinical Immunology, 2004).
What pollen food syndrome is
Some pollen proteins look like proteins in fruits, vegetables or nuts. If your immune system reacts to the pollen's, it can react to the food's as well. It usually shows as itching or tingling in the mouth, lips or throat straight after eating the food raw.
What cooking does depends on the protein. PR-10 proteins (birch, alder) and profilins (grass, ragweed) are broken down by heat and digestion and usually cause mild symptoms. LTPs (olive, plane tree, and mugwort with peach and mustard) and gibberellin-regulated proteins (cypress) survive cooking and digestion and can cause severe reactions; around the Mediterranean, LTPs are the leading cause of food anaphylaxis in adults.
Sources: Oral Allergy Syndrome (OAS) or Pollen Food Syndrome (American Academy of Allergy, Asthma & Immunology, 2026); Oral Allergy Syndrome (Pollen Food Syndrome) factsheet (Allergy UK, 2021); BSACI guideline for the diagnosis and management of pollen food syndrome in the UK (Skypala et al.) (Clinical & Experimental Allergy, 2022); Non-specific lipid-transfer proteins: allergen structure and function, cross-reactivity, sensitization, and epidemiology (Skypala et al.) (Clinical and Translational Allergy, 2021); EAACI Molecular Allergology User's Guide 2.0 (Dramburg et al.) (EAACI, Pediatric Allergy and Immunology, 2023).
Frequently asked questions
What is oral allergy syndrome?
A reaction to a plant food in people with pollen allergy, because some pollen proteins look like the food's. It usually shows as itching or tingling in the mouth, lips or throat when eating the food raw. It is also called pollen food syndrome.
Does cooking the fruit stop the reaction?
It depends on the pollen. With birch, alder, grass and ragweed, the protein involved is usually destroyed by heat and cooked fruit is usually tolerated, with exceptions such as soy, nuts and celery. With olive, plane tree, cypress and mugwort, the protein survives cooking: cooking does not make the food safe.
Can it be serious?
It is usually mild, but not always. Reactions linked to LTPs (olive, plane tree, and peach and mustard with mugwort) and to gibberellin-regulated proteins (cypress) can reach anaphylaxis. If you have trouble breathing, throat swelling or feel faint, call emergency services.
Do I have to stop eating these foods?
Not because of this list. Being sensitised does not always mean reacting: in one study, only 6 of 26 patients with antibodies to watermelon had symptoms when they ate it. Avoid the foods that give you symptoms and ask your allergist which ones you need to avoid.
Where does this information come from?
From the European Academy of Allergy and Clinical Immunology's molecular allergology guide (EAACI) and studies in medical journals, linked in each section. A food is only listed if at least one reliable source links it to that pollen.
Respira
