Soybean is a food which may result in allergy symptoms in sensitised individuals.

Soybean Allergy Test: Allergen Exposure

The soybean is one of the most important global crops, and the most widely used of the legumes, particularly in Asia, where it is a primary foodstuff.

The bean can be used fresh, or can be processed into soybean flour, flakes, grits, or soy milk, or it can be pressed for oil.

Soybean oil is included in salad oil, margarine and industrial components, and in linoleum and glue in the plywood industry, where it is considered an occupational allergen.

Soy sauce, or shoyu, is a fermented product of soybean and wheat and used in many Asian cuisines as a flavour enhancer.

Soya mince is a good source of protein and may be used as a replacement for meat or fish. Unlike other pulses, Soya beans have a healthy balance of amino acids and contain significant amounts of (mostly unsaturated) fat.

Soybean can be a hidden allergen, as soya protein is found almost ubiquitously in processed foods. In a Spanish study, the most frequent sources of hidden soy allergens were boiled ham, sausages, cheese puffs, pre cooked dishes, desserts and gravy.

Soybean Allergy Test: Allergen Description

Several major allergens present in soybean have been characterised, among them a profilin, a hydrophobic protein, a Bet v 1 homologue, an albumin, a vicilin-like globulin, a protease, an agglutinin, an oleosin, a trypsin inhibitor and an isoflavone reductase.

Soybean Allergy Test: Potential Cross-Reactivity

Studies of soybean have demonstrated several antigenic components with considerable cross-reactivity with other legume family members.

A patient who suffered adverse reactions when eating peas, lentils, peanuts, kidney, lima and navy beans experienced the most severe episodes following ingestion of soybean products.

In a report on 3 patients who experienced anaphylaxis to a soy drink, cross-reactivity of soy protein with birch pollen allergens was identified as the cause of their severe reactions.

Soybean Allergy Test: Clinical Experience

Soybean may commonly induce symptoms of food allergy in sensitised individuals. Dust from soybean storage or transport has been reported to result in exacerbation of asthma, and dust from soybean flour may precipitate asthma in bakers.

There are 2 main types of soy food-allergenic reactions. IgE-mediated reactions may result in respiratory, cutaneous, and gastrointestinal symptoms, and anaphylaxis. Delayed non-IgE-mediated reactions, including soy-induced enterocolitis, may be experienced.

A number of studies concluded that soybean, among other foods, may be a common food allergen in atopic dermatitis in children. There is evidence that soy allergens may pass to infants through breast milk, resulting in sensitisation.

In soybean allergic people, ingestion may result in anaphylaxis, inducing respiratory, cutaneous, cardiovascular, and gastrointestinal symptoms, and even death.

Food protein-induced enterocolitis (FPIES) in infants as a result of soy ingestion has been reported by a number of authors.

Rhinitis, conjunctivitis and bronchospasm following the inhalation of soybean dust from a bean-bag toy have been reported.

Occupational asthma in bakers, millers and workers in food processing plants may be caused by soy flour. Animal food processing plant workers may also come into contact with soybean flour, resulting in sensitisation.