Table of Contents

f316 Rapeseed Scientific Information Summary Allergen Route of Exposure Clinical Relevance Molecular Aspects Compiled By

Whole Allergen

f316 Rapeseed

f316 Rapeseed Scientific Information

Type:

Whole Allergen

Display Name:

Rapeseed

Route of Exposure:

Ingestion

Family:

Brassicaceae

Species:

Brassica napus

Latin Name:

Brassica napus

Other Names:

Rape Seed, Rape, Oilseed Rape, Rapa, Rappi, Canola

Summary

Rapeseed is part of the Brassicaceae family and is an important source of edible oil worldwide. While the refining process for this oil should result in the removal of all allergens, Bra n 1, the major allergen present in rapeseed, is not always destroyed and could cause allergy via ingestion. Despite this, no clinical instances of allergy have occurred through ingestion of rapeseed oil, with reactions being limited to positive skin prick testing in sensitized individuals. Although rare, clinical reports of IgE-mediated reaction to inhaled rapeseed allergens have been reported to cause respiratory issues in exposed occupational workers.

Allergen

Nature

Rapeseed is a bright-yellow flowering plant, which is grown mainly for its seed rich in oil and is the third-largest source of vegetable oil in the world (1). The Brassicaceae family contains many well-known vegetables, such as cabbage, turnip, broccoli, cauliflower and Brussels sprout. The seeds from Brassica species have been used as oils for more than 4,000 years, initially as lamp and industrial lubricant oils, and more recently as edible oils (2). Rapeseed is now an important source of edible oil and a protein-rich livestock feed (3).

Taxonomy

Taxonomic tree of Rapeseed (4)
Domain	Eukaryota
Kingdom	Plantae
Phylum	Magnoliophyta
Subphylum	Angiospermae
Class	Magnoliopsida
Family	Brassicaceae
Genus	Brassica.

Taxonomic tree of Rapeseed (4)

Route of Exposure

Main

Ingestion

Clinical Relevance

The majority of rapeseed is consumed as oil, available as cold-pressed or refined oil (1). Refining oils should result in the near-complete removal of proteins responsible for allergic reactions, therefore preventing allergic reactions upon ingestion (5). However, the major allergens present in rapeseed are reported to be extremely resistant to pepsin digestion and denaturation, and are therefore not destroyed during conventional food processing (6). During the manufacture of cold-pressed oils some protein from the seeds may remain. Therefore, allergic reaction to some rapeseed oils remains a possibility (1). However to date, no clinical evidence of allergic reactions following the ingestion of rapeseed oil has been reported (6). Evidence of sensitization based upon skin prick testing results has been observed in clinical studies (1).

Allergic rhinitis

In a study assessing sensitization rates covering 20 years to weed pollens in 6,220 patients with suspected allergic rhinitis or bronchial asthma, 20.4% of those undergoing a skin prick test to rapeseed (362/1,771) were positive for the first decade from 1998-2007. This increased further to 31.3% (431/1,378) during the second decade, from 2008-2017 (7).

Asthma

Clinical cases of allergy from inhaled rapeseed allergens are limited. One study assessed 3 farmers with occupational asthma who had positive skin prick tests and serum specific IgE levels towards rapeseed extract. The farmers also had positive bronchial provocation tests to rapeseed allergen extract, suggesting that rapeseed, when used in animal fodder, can be a cause of occupational allergy in farmers (8). An earlier study also reported that inhalation of oilseed rape dust caused IgE-mediated bronchoconstriction in an exposed worker of the grain industry (9).

Molecular Aspects

Allergenic molecules

Table adapted from Allergome.org (10).

Allergen	Source
Bra n 1	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed
Bra n 1.0101	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed
Bra n 4	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed
Bra n 7	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed
Bra n 8	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed
Bra n PG	Brassica napus, Brassicaceae, Canola, Plants, Rapeseed

Allergen	Source

The major allergen identified in rapeseed (Bra n 1) was identified as a 2S albumin termed napin, which is the seed storage protein representing approximately 20% of the total protein. Napins consist of a small and large chain linked by disulphide bonds and are reported to be resistant to pepsin digestion and denaturation. Therefore it is possible that these allergens are not destroyed during conventional food processing (6).

Cross-reactivity

Cross-reactivity between different foods within the Brassicaceae family have been reported, especially with mustard seeds (1). An IgE and IgG cross-reactivity between rapeseed and mustard allergens (2S albumins) were present in a rapeseed allergic patient (11). Despite this, clinical cases of cross reactivity involving rapeseed are limited.

A study of 1,887 Finnish children with atopic dermatitis found that 11 % (206/1887) had positive skin prick tests to rapeseed. However, none of the children had clinical manifestations such as immediate or delayed symptoms from this sensitization. A subsequent study found that French children with atopic dermatitis and skin prick positive to turnip rape or rapeseed were polysensitized to various foods and pollens. These reactive children frequently had associated asthma (36 %) and allergic rhinitis (44 %) (1).

Compiled By

Author: RubyDuke Communications

Reviewer: Dr. Michael Thorpe

Last reviewed:February 2022

References

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Wu D, Liang Z, Yan T, Xu Y, Xuan L, Tang J, et al. Whole-genome resequencing of a world-wide collection of rapeseed accessions reveals genetic basis of their ecotype divergence. Molecular Plant. 2018;12.
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Forkel S, Beutner C, Heetfeld A, Fuchs T, Schön MP, Geier J, et al. Allergic Rhinitis to Weed Pollen in Germany: Dominance by Plantain, Rising Prevalence, and Polysensitization Rates over 20 Years. Int Arch Allergy Immunol. 2020;181(2):128-35.
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Suh CH, Park HS, Nahm DH, Kim HY. Oilseed rape allergy presented as occupational asthma in the grain industry. Clin Exp Allergy. 1998;28(9):1159-63.
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Monsalve RI, González de la Peña MA, López-Otín C, Fiandor A, Fernández C, Villalba M, et al. Detection, isolation and complete amino acid sequence of an aeroallergenic protein from rapeseed flour. Clin Exp Allergy. 1997;27(7):833-41.