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  Substance Info: (and synonyms)
Rape seed pollen / Rapeseed pollen

Background Info:

Pollen from Rape plant, as opposed to the allergen from the Rapeseed.

See: Rape seed / Rapeseed, and, Rapeseed oil / Oilseed rape

Common Names: Rape, Rapeseed, Rape seed, Canola

Brassica napus is a variable species, with three subspecies. These include the B. napus napobrassica (rutabagas / Swedes), B. napus pabularia (Siberian kale, Hanover salad, etc.), and B. napus oleifera (rape, canola, etc.).

Rape is an annual plant similar to turnip and rutabaga. It is thought that Brassica napus originated from a hybridization between the turnip (B. rapa) and kale (B. oleracea acephala). Rape originated in northern Europe and was cultivated in the Mediterranean area, but is now grown throughout the world. Canola, a selected genetic variant of rape, was developed in the late 1970's in Manitoba, Canada, as a more nutritious source of vegetable oil than rapeseed.

The rape plant is an annual/biennial growing up to 1.2 m, with turnip-like flat leaves 10 - 30 cm long, slick, and generally lobed. Unlike turnips, they have no swollen root, only a thin taproot.

The plant flowers from May to August, producing yellow, cross- shaped flowers with four petals. The flowers are hermaphrodite (have both male and female organs) and are primarily insect pollinated. The plant is also self-fertile. During the 3-4 weeks flowering period, crop fields become a conspicuous part of the rural landscape during flowering, when bright yellow flowers are produced and a characteristic odour from the released volatile organic compounds are evident.

The pollen grains are covered with a sticky lipoidal substances which results in the grains sticking together and thus reducing the ability for the pollen to be airborne for a significant period, and thus this pollen is usually a fraction of the total atmospheric pollen load. It is possible that dead grains or fragments lacking the sticky coating could become airborne. Sickle shaped pods containing tiny round seeds are produced.

b. Environment
Rape is cultivated in fields, but the plant may escape and grow on banks of streams, ditches and arable fields.

Rape is grown primarily for green livestock fodder, its seed oil (called colza oil), and birdseed. The oil contained in the seed of some varieties of this species can be rich in erucic acid which is toxic. However, modern cultivars have been selected which are almost free of erucic acid e.g., canola oil.

 

Adverse Reactions:

IMMUNE REACTIONS


[ 1 / 7 ]

Possible adverse effects caused by oilseed rape cultivation
have been suggested since many years, especially in Britain, and several reports discuss the scientific basis of such effects.These were mainly attributed to volatile organic compounds that may be involved in the irritancy and/or in the allergenicity of rapeseed proteins. There is now a general agreement that oilseed rape pollen is allergenic, with oligo- or mono-sensitized patients and a high prevalence of sensitization in cases of occupational exposure. (Chardin 2003 ref.7999 3)

Reference:
Chardin H, Mayer C, Senechal H, Poncet P, Clement G, Wal JM, Desvaux FX, Peltre G. Polygalacturonase (pectinase), a new oilseed rape allergen. Allergy 2003;58(5):407-11



[ 2 / 7 ]

In 4468 patients with suspect inhalant allergy investigated between June 1994 and May 1995, routine skin prick testing revealed rapeseed pollen sensitivity in 7.1% of pollen-allergic patients. In all, monovalent sensitization was detected in nine patients. (Hemmer 1997 ref.1406 3)

Reference:
Hemmer W, Focke M, et al. Oilseed rape pollen is a potentially relevant allergen. Clin Exp Allergy 1997;27(2):156-61



[ 3 / 7 ]

In 25 residents in a small Scottish village reporting symptoms when oilseed rape virtually surrounded the village, varied during the growing season of the crop and was at its highest coincident with peak flowering. At the same period of the following year when the crop was absent, symptom reporting was significantly lower. The symptoms which correlated most strongly with peak oilseed rape flowering were sneezing, cough, headache, eye irritation and the total of these and other symptoms. Increased symptoms were reported by 12 of the participants though only seven of these were judged to be atopic. The symptoms did not correlate with levels of oilseed rape pollen but there is no clear evidence as to which of the other factors associated with the crop might be the cause. (Parratt 1995 ref.5063 5)

Reference:
Parratt D, Macfarlane Smith WH, Thomson G, Cameron LA, Butcher RD. Evidence that oilseed rape (Brassica napus ssp. oleifera) causes respiratory illness in rural dwellers. Scott Med J 1995;40(3):74-6



[ 4 / 7 ]

In this study, of patients with a history of symptoms to oilseed rape pollen, only 2 of 23 tested, showed evidence of allergy to oilseed rape and only 10 of 23 tested, including these two, were atopic. Eye, nasal, and headache symptoms increased in the season in cases, which validated the questionnaire used in the previous cross sectional survey. 12 of 16 cases tested and seven of 15 controls showed a seasonal fall in PC20; the fall in the cases was significantly greater than in the controls. Peak flow charts showed no evidence of fall or of increased variability during the season. The authors conclude that people who complained of symptoms in relation to the flowering of oilseed rape were rarely allergic to the plant and fewer than half were atopic. Nevertheless, they usually showed increased bronchial reactivity during the season, which may have been due in some cases to other allergens but in others to non-specific irritant effects of the air. (Soutar 1995 ref.1303 3)

Reference:
Soutar A, Harker C, et al. Oilseed rape and bronchial reactivity. Occup Environ Med 1995;52(9):575-80



[ 5 / 7 ]

Random samples of 1000 adults from the general practice populations of two villages surrounded by oilseed rape fields, and 1000 adults from one village far from such cultivation, were taken. On a previously validated questionnaire, there were small but significant excesses of cough, wheeze, and headaches in spring in the oilseed rape area (2.3% v 1.1%, 6.8% v 4.6%, and 4.8% v 2.8%, respectively). Counts of oilseed rape pollen were generally low except adjacent to fields. Oilseed rape was shown to give off terpenes and these were detected close to fields. (Soutar 1994 ref.5065 9)

Reference:
Soutar A, Harker C, Seaton A, Brooke M, Marr I. Oilseed rape and seasonal symptoms: epidemiological and environmental studies. Thorax 1994;49(4):352-6



[ 6 / 7 ]

Asthma and pollinosis - report of a case. (Colldahl 1954 ref.3675 9)

Reference:
Colldahl H. Rape pollen allergy - report of a case Acta Allergol 1954;7:367-9



[ 7 / 7 ]

See: Rape seed / Rapeseed / Oilseed rape
Rape seed pollen / Rapeseed pollen
Rapeseed oil

Reference:
Editor Comment Editorial comment, common knowledge, or still to add - -




Non-Immune reactions


[ 1 ]

Irritants have been postulated as the cause for bronchospasm from contact with this plant (instead of the pollen). 22 volatile compounds were identified as being emitted during the flowering period. The main constituents were alpha-farnesene (a sesquiterpene); beta-myrcene (a monoterpene); linalool (a monoterpene alcohol) and the 'green leaf' volatile (E)-3-hexen-1-ol acetate. These compounds constituted between 50 and 87% (mean 68%) of the total volatiles emitted in all of the entrainments carried out with flowering oilseed rape plants. The remaining constituents consisted of a range of compounds including other terpenoids, the characteristic 'green leaf' volatile (E)-3-hexen-1-ol, short chain alcohols and ketones, organic sulphides and nitrogen-containing compounds. These were generally present as minor constituents but some plant entrainments revealed that higher relative amounts could be emitted. This was particularly apparent for dimethyl disulphide, 3-methyl-2-pentanone, 3-hydroxy-2-butanone, sabinene, isomyrcenol and (E)-3-hexen-1-ol. (Butcher 1994 ref.5064 8)

Reference:
Reorganization process. Data in process of being reorganized. Editorial staff 2006



[ 2 ]

Thiocyanate from rapeseed feeding of cows decreases milk iodine content, probably by competitive inhibition of sodium iodide symporter (NIS) in the mammary gland. Alterations in feeding of dairy cows may alter the iodine content of consumer milk, and this may influence the risk of thyroid diseases in the population. Thiocyanate inhibition of iodine transport into milk may also be operative in humans with a high thiocyanate intake. This could further impair iodine status in breastfed children in low-iodine intake areas of the world. It can be speculated that a low-iodine content of mother's milk because of inhibition of NIS in the mammary gland may be one factor of importance for development of myxedematous cretinism. (Laurberg 2002 ref.9857 3)

Reference:
Laurberg P, Andersen S, Knudsen N, Ovesen L, Nohr SB, Bulow Pedersen I. Thiocyanate in food and iodine in milk: from domestic animal feeding to improved understanding of cretinism. Thyroid 2002;12(10):897-902



[ 3 ]

Irritant symptoms, e.g., cough, headache, are usually experienced by OSR sufferers, suggesting that it may be volatile vapors being released. (Galloway 2000 ref.3674 4)

Reference:
Galloway D Oilseed rape - allergen or irritant? Editorial Clin Exp Allergy 2000;30(3):308-9



[ 4 ]

Irritants have been postulated as the cause for bronchospasm from contact with this plant (instead of the pollen). 22 volatile compounds were identified as being emitted during the flowering period. The main constituents were alpha-farnesene (a sesquiterpene); beta-myrcene (a monoterpene); linalool (a monoterpene alcohol) and the 'green leaf' volatile (E)-3-hexen-1-ol acetate. These compounds constituted between 50 and 87% (mean 68%) of the total volatiles emitted in all of the entrainments carried out with flowering oilseed rape plants. The remaining constituents consisted of a range of compounds including other terpenoids, the characteristic 'green leaf' volatile (E)-3-hexen-1-ol, short chain alcohols and ketones, organic sulphides and nitrogen-containing compounds. These were generally present as minor constituents but some plant entrainments revealed that higher relative amounts could be emitted. This was particularly apparent for dimethyl disulphide, 3-methyl-2-pentanone, 3-hydroxy-2-butanone, sabinene, isomyrcenol and (E)-3-hexen-1-ol. (Butcher 1994 ref.5064 8)

Reference:
Butcher RD, MacFarlane-Smith W, Robertson GW, Griffiths DW. The identification of potential aeroallergen/irritant(s) from oilseed rape (Brassica napus spp. oleifera): volatile organic compounds emitted during flowering progression. Clin Exp Allergy 1994;24(12):1105-14




Occupational reactions


[ 1 ]

A low prevalence of allergy to oilseed rape pollen (less than 0.2%) unless the subjects were occupationally exposed was shown. (Fell 1992 ref.5066 8)

Reference:
Fell PJ, Soulsby S, Blight MM, Brostoff J. Oilseed rape--a new allergen? Clin Exp Allergy 1992;22(4):501-5




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