[Anaphylactic shock due to French galette. Type I allergic reaction to buckwheat]

A Review on Epidemiological and Clinical Studies on Buckwheat Allergy

BACKGROUND

Cultivated buckwheat include two species originating from China: common buckwheat (Fagopyrum esculentum) and tartary buckwheat (Fagopyrum tartaricum). Buckwheat can cause IgE-mediated allergy, including severe allergic reactions and anaphylaxis. Exposure can occure when eating buckwheat food (food allergen), when producing or handling buckwheat food (occupational exposure) or when sleeping on buckwheat husk pillows (houeshold environmental exposure).

METHODS

A search on buckwheat allergy in the medical datbase PubMed from 1970-2020.

RESULT

A number of allergenic proteins have been identified in common buckwheat (e.g., Fag e 1, Fag e 2 and Fag e 3) and in tartary buckwheat (e.g., Fag t 1, Fag t 2, Fag t 3). Clinically relevant cross-reactivity has been described between buckwheat and peanut, latex, coconut, quinoa, and poppy seed. The prevalence of buckwheat allergy in the population can be estimated as 0.1-0.4% in Japan, Korea and buckwheat consuming areas of China. Among patients in allergy clinics in different countries, 2-7% has confirmed buckwheat allergy. School studies from Japan and Korea found 4-60 cases of buckwheat-related anaphylaxis per 100,000 school children. The incidence of severe allergic reactions to buckwheat, including anaphylaxis, can be estimated as 0.1-0.01 cases per 100,000 person-years.

CONCLUSIONS

Buckwheat allergy is a neglected allegy deserving further attention but severe allergic reactions are rare.

Development of a sandwich enzyme-linked immunosorbent assay (ELISA) for detection of buckwheat residues in food

Buckwheat is a pseudocereal (an eudicot with seed qualities and uses similar to those of monocot cereals, family Poaceae) that is consumed in some Asian countries as a staple, and in some western countries as a health food. Allergic reactions to buckwheat are common in some countries. The objective was to develop a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) to detect traces of buckwheat that might inadvertently contaminate other foods in order to assure accurate labeling and consumer protection. Buckwheat-specific antibodies produced in 3 species of animals were tested for specificity and titer by direct ELISA and immunoblot. A sandwich ELISA was developed utilizing pooled rabbit antibuckwheat sera to capture buckwheat proteins and pooled goat antibuckwheat sera, followed by enzyme-labeled rabbit antigoat immunoglobulin G (IgG), to detect bound buckwheat proteins. The lower limit of quantification (LOQ) of the sandwich ELISA was 2 parts per million (ppm) of buckwheat in the presence of complex food matrices. The ELISA is highly specific with no cross-reactivity to any of 80 food ingredients and matrices tested. Validation studies conducted with buckwheat processed into noodles and muffins showed greater than 90% and 60% recovery, respectively. The percent recovery of buckwheat from noodles was similar to that achieved with a commercial buckwheat ELISA kit (ELISA Systems Pty. Ltd., Windsor, Queensland, Australia) at high buckwheat concentrations. However, the sensitivity of this ELISA was greater than the commercial ELISA. This newly developed ELISA is sufficiently specific and sensitive to detect buckwheat residues in processed foods to protect buckwheat-allergic subjects from potential harm. Practical Application: Buckwheat is becoming a common food ingredient in a number of processed foods due to potentially beneficial nutritional properties, without the celiac disease inducing glutenin proteins of wheat and related cereals. However, buckwheat causes allergy in some individuals and must be labeled and tested accurately to protect those with allergy to buckwheat. We describe the development of a new test assay to help food producers ensure that buckwheat is not present in foods that are not intended to contain buckwheat.