Type:
Whole Allergen
Whole Allergen
Whole Allergen
Japanese millet
Poaceae (Gramineae)
Echinochloa crus-galli
See common background for Millets.
The name Millet is used to describe seeds from several taxonomically divergent species of grass. They are grown mostly in marginal areas and under agricultural conditions in which major cereals fail to give sustainable yields (1).
See common background for Millets.
Japanese millet and the other Millets are not closely related to Wheat.
Japanese millet is the fastest growing of all Millets and produces a crop in 6 weeks. It is grown in India, Japan and China as a substitute for Rice when the paddy fails. It is grown as a forage crop in the United States and can produce as many as 8 harvests per year. The height of the plant varies between 50 and 100 cm (1).
See common background for Millets.
The Millets are important sources of food for humans and animals. But in the West, with the exception of natural food stores, Millet is sold mainly as bird feed.
No allergens from this plant have yet been characterised.
A number of proteins have been isolated and described as occurring in Japanese millet. The allergenic potential of these proteins was, however, not evaluated.
Barnyard millet, Common millet, Little millet, Foxtail millet, and Kodo millet were studied. The protein contents of the selected decorticated Millets were found to be 11.0, 12.3, 12.9, 10.5 and 10.6% respectively. Prolamin is a major storage protein in Foxtail millet, whereas glutelin is a major storage protein in all the other Millets. A protein band at the molecular weight range of 20 kDa was found to be homologous in all except Proso millet (2).
A Foxtail millet glutelin of 60 kDa (MG60) has been isolated. The primary structure at the N-terminal end was almost identical to that of the granule-bound starch synthase (GBSS) proteins from Rice, Barley, Maize, Wheat and Potato. Common epitopes from these starch-storing cereals were corroborated by immunoblot analysis, strongly suggesting a close relationship (3).
In a study, the antigenic relationships among "minor Millets" (Barnyard, Little and Foxtail millets) and other cereals (Wheat, Maize, Rice, Sorghum, Finger millet and Pearl millet) were evaluated using an antibody raised against a 20 kDa prolamin from Kodo millet. It was demonstrated that the prolamin was related to the prolamins from the other plants. Rice was the only common cereal that did not cross-react immunologically with the 20 kDa prolamin of Kodo millet (4).
A subtilisin inhibitor has been isolated from seeds of Foxtail millet. (5)
Proteinase inhibitors (trypsin/chymotrypsin) have been demonstrated to be present in Finger millet, Sorghum, Pearl millet, Foxtail millet, and Japanese millet (6). The amino acid sequence of an isolated trypsin inhibitor (7) had a high degree of homology to Bowman-Birk type inhibitors from leguminous and gramineous plants (8).
Cross-allergenicity among Rice, Wheat, Maize, Japanese millet and Foxtail millet was examined by IgE antibody determination and RAST inhibition studies, and significant close correlations among the 5 cereal grain extracts were demonstrated. A Rice protein of 16 KDa was shown to be one of the major allergens in Rice grain extracts (9-10). The protein showed sequence homology to Wheat alpha-amylase inhibitor and Barley trypsin inhibitor (11). The clinical relevance of this protein was not assessed.
A Rice protein of 16 kDa has been shown to be involved in cross-allergenicity among antigens in Rice, Wheat, Maize, Japanese millet and Foxtail millet (10). The clinical relevance of this allergen was not examined.
Hypersensitivity to cereals may occur via inhalation or ingestion. But reported allergy to Japanese millet is rare.
With the increasing popularity of "natural foods", Millet is more frequently included in various dishes, which might raise the incidence of Millet-related allergic reactions. Patients with adverse reactions to Gluten may substitute Millet for gluten-containing cereals.
Several studies of adults and children with atopic dermatitis and/or respiratory disease revealed the presence of IgE antibodies to Japanese millet (9,12-15).
Crude extracts of Millet may contain aflatoxins (16).
Millet diets rich in C-glycosylflavones are goitrogenic (17).