This is a simplified description of Bet v 1 proteins – there are more resources available at the bottom of the page for further reading for those who are interested in knowing more.

What are Bet v 1 proteins?

The scientific name for birch tree is Betula verrucosa. Bet v 1 is the name of the most common allergen found in birch tree pollen (Learn more about how allergy proteins are named). It is important and well studied as it is the sensitising allergen which can go on to cause allergies to multiple pollens and foods.

Proteins of a similar shape are referred to as "Bet v 1-like proteins" and are also known as PR-10 proteins (pathogenesis related) as they are used by plants as a defence against disease and predators.

These proteins are considered to be secondary allergens as they only cause allergic reactions as a result of cross reactivity between similarly shaped proteins.

These proteins vary from species to species in how the allergenicity is changed due to heat. Most studies show Bet v 1 proteins are generally not heat resistant and will be broken down after cooking, processing or removal of fruit skin/rind.

Which foods contain Bet v 1 proteins?

The World Health Organization (WHO) recognises 25 Bet v 1 allergens, 16 of these are categorised as food allergens where Bet v 1 proteins have been identified as causing allergic reactions after consumption of food.

In the top 14 foods, soyabeans, peanut, celery and walnut all contain Bet v 1 proteins.

Fruits and vegetables containing these proteins are mung beans, tomato, raspberry, pear, peach, cherry, apricot, apple, strawberry, carrot, chicory and kiwi.

This list is not exhaustive, please visit the Food Allergy Index to see a list of foods, each page will show whether studies have linked them to Bet v 1 allergies.



You can download a Bet v 1 Protein Factsheet from the Allergy Resources Ko-fi Shop for just $0.50 (£0.40 or €0.45). This has up to date information on which foods contain linked allergens and what to avoid if you think you have an allergy to Bet v 1 proteins.

Which pollens contain Bet v 1 proteins?

There are 9 pollen allergens associated with Bet v 1 proteins including holly, oak, hornbeam, beech, hazel, chestnut, alder and of course, birch trees.

What symptoms do they cause?

Allergic reactions as a result of exposure to Bet v 1 are generally less severe than a classic IgE allergic reaction. There is a wide range of symptoms, often described as Oral Allergy Syndrome, these include itchy mouth and tongue and sore throat. More severe reaction to Bet v 1 proteins may include urticaria (hives or welts), angioedema (swelling under the skin), nausea, abdominal pain, vomiting or breathlessness and in rare cases, anaphylactic shock.

Pollen Food Allergy Syndrome

If you are allergic to multiple plant pollens and have OAS type symptoms to at least 3 foods containing Bet v 1 proteins you may be suffering from Pollen Food Allergy Syndrome.

What is the importance of knowing whether a reaction is to Bet v 1 or other allergens?

Multiple allergies are becoming more common and this often leads people to impose a strict restrictive diet on themselves. This can lead to a poor diet lacking in essential nutrients and frustration over a lack of eating options. Knowing which foods are the most likely to be causing your reactions can bring more options back into your diet.

This is why food diaries continue to be an important tool in diagnosis of your allergies – noting the times reactions took place and what medications were taken are a necessary starting point for a proper diagnosis.

There is more information on food diaries HERE.

DermNet NZ - Pollen Food Allergy Syndrome

Allergen Encyclopedia - Birch Pollen

Science Direct - Oral Allergy syndrome

University of Worcester - Allergenic Pollen Types

Allergen profiles in Japanese children with pollen-food allergy syndrome: Insights from a multicenter cross-sectional study, 2024

IgE to cyclophilins in pollen allergic children: epidemiological, clinical and diagnostic relevance of a neglected panallergen, 2024

Molecular allergy diagnosis is sensitive and avoids misdiagnosis in patients sensitized to seasonal allergens, 2023

An Overview of Fruit Allergens: Structural, Functional, Phylogenetical, and Clinical Aspects, 2023

Impact of meteorological parameters and air pollutants on airborne concentration of Betula pollen and Bet v 1 allergen, 2023

The History and Science of the Major Birch Pollen Allergen Bet v 1, 2023

Analysis of Protein Sequence Identity, Binding Sites, and 3D Structures Identifies Eight Pollen Species and Ten Fruit Species with High Risk of Cross-Reactive Allergies, 2022

Prevalence, clinical presentation, and associated atopic diseases of pediatric fruit and vegetable allergy: A population-based study, 2022

Bet v 1-specific IgE levels and PR-10 reactivity discriminate silent sensitization from phenotypes of birch allergy, 2019

Sensitization to PR-10 proteins is indicative of distinctive sensitization patterns in adults with a suspected food allergy, 2017

How relevant is panallergen sensitization in the development of allergies? 2016

Panallergens and their impact on the allergic patient, 2010

The Bet v 1 fold: an ancient, versatile scaffold for binding of large, hydrophobic ligands, 2008

Let me know if you found any of these interesting or useful. If you spot an article or research that you think is interesting you can message me or tag me on Facebook or Twitter - links at the bottom of the page.