Allergen in soy oils

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

Isotretinoin-associated exercise-induced anaphylaxis in a patient with birch pollinosis and soybean sensitization: case presentation and literature review

Background

Peanut and soybean allergies are listed as contraindication in the package leaflet of isotretinoin, a widely used treatment of acne vulgaris. Cross-reactivity between PR10-proteins in peanut, tree nuts, and soybean is particularly common in patients with birch pollinosis and may lead to anaphylactic reactions in sensitized patients after intake of soybean oil containing isotretinoin capsules.

Case presentation

Here, we describe a young man with hazelnut and birch pollen allergy, who experienced exercise-induced anaphylaxis after isotretinoin intake on the third day of treatment. A complete allergy work-up was carried out, and sensitization to both peanut and soybean PR10-proteins was confirmed. However, oral provocation with isotretinoin remained negative in the absence of intense physical activity and longterm treatment was well tolerated.

Conclusion

To our knowledge, this is the first report of an exercise-induced anaphylaxis due to isotretinoin therapy. Our literature review to assess tolerability of isotretinoin in patients allergic to peanut, tree nuts or soybean revealed only one other case of anaphylaxis in a cashew-nut allergic patient sensitized to soybean PR10-protein Gly m 4. While there are no reports on soybean allergic patients treated with isotretinoin, the vast majority of peanut or tree nut allergic patients tolerated isotretinoin. Therefore, we conclude that sensitization to soybean, peanut or tree nuts should not preclude isotretinoin therapy. Particular caution is however warranted in patients with soybean sensitization. Pre-treatment oral challenges with isotretinoin may be recommended and physicians should be aware of the potential role of cofactors.

Antigenic activity and epitope analysis of β-conglycinin hydrolyzed by pepsin

BACKGROUND

Soybean is among the 'big eight' allergenic foods, and β-conglycinin, the main antigenic protein of soybean, has high levels of antigenic activity. Why the antigenic activity of soybean β-conglycinin is not eliminated by enzymatic hydrolysis is not clear. In this study, changes in the molecular composition and antigenicity of β-conglycinin hydrolyzed by pepsin were analyzed and it was determined whether complete sequential epitopes exist in the resulting hydrolysates. The nature and antigenic activity of protein subunits obtained after β-conglycinin hydrolysis were also assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and competitive enzyme-linked immunosorbent assay, respectively.

RESULTS

The residual antigenic activity of β-conglycinin was 52%, α'- and α-subunits completely disappeared, the 49 kDa fraction partially disappeared, and peptides measuring 27 and 23 kDa were newly formed after 60 min of enzymatic hydrolysis. Prolonged enzymatic hydrolysis did not result in remarkable changes in these peptides; thus, the peptides show some resistance to enzymatic hydrolysis. The amino acid sequences of the peptide chains were analyzed by matrix-assisted laser desorption / ionization-time of flight mass spectrometry and aligned with the related sequences in the corresponding protein and antigen databases. Ten complete sequential epitopes were identified in the residual 49 kDa fraction, of these epitopes, two were from α-subunits and eight were from β-subunits.

CONCLUSION

The presence of complete sequential epitopes in hydrolysates obtained from the enzymatic hydrolysis of soybean is an important reason for the incomplete disappearance of the antigenic activity of β-conglycinin. © 2020 Society of Chemical Industry.

Food allergen labelling: "May contain" evidence from Malaysia

Food allergen labelling is mandatory and regulated whilst precautionary allergen labelling (PAL) remains voluntary in most countries. It is the aim of this study to identify the food allergens declared in food products sold in a developing country and to what extent food allergens and PAL are emphasised in the products. A total of 505 food and beverages (snacks, baked goods, confectionary, baby food, condiments & jams, beverages, powder & paste, instant food, chilled & frozen food and canned food) were evaluated in Malaysia. Soybean represents the largest group of food allergen declared in labels, followed by wheat and milk products. Thirteen variations of contains statement were found with "Contains [allergen(s)]" being the most common (55.02%). There were 22 different types of "may contain" statements with 'May contain traces of [allergen(s)]' being the most common advice labelling used (55.41%). Different font type or emphasis such as brackets (51.57%) and bold font (33.86%) were used to inform consumers about presence of allergens. The national regulations on food allergen labelling are then critically contrasted with other Asian countries and the EU Regulation No. 1169/2011, which represents one of the most stringent food regulations in the world. Improving current allergen labelling limitations and practices would be of great benefit to consumers to prevent risk of food hypersensitivity.

Prediction and characterization of the linear IgE epitopes for the major soybean allergen β-conglycinin using immunoinformatics tools

The α subunit of β-conglycinin is a major allergen in soybean. The objective of this study was to predict and identify the linear immunoglobulin (Ig)E epitopes of the soybean α subunit of β-conglycinin. Three immunoinformatics tools were used to predict the potential epitopes and were confirmed by dot-blot inhibition using sera from soybean allergic subjects. As a result, 15 peptides were predicted and assembled by solid-phase synthesis. Eleven epitopes were identified by the dot-blot inhibition test. Moreover, peptide 3 had IgE binding capability with all sera(5/5) tested, while peptide 1, 4, 6, 8 and12 could bind to 4/5 of the sera samples. Secondary structure prediction of peptide 3 and circular dichroism test validated that the structure of peptide 3 was a random coil.

Quantification and partial characterization of the residual protein in fully and partially refined commercial soybean oils

A method has been developed to determine residual protein in refined oils, a potential trigger of allergic reactions. High-pH bicarbonate or borate buffers were found to be the most effective extractants, residual oil protein comprising a mixture of proteins of M(r) 6000-100000. Extracted protein could be quantified with superior precision using 3-(4-carboxybenzoyl)quinolone-2-carboxaldehyde (CBQCA). Residual protein content determined in a set of oils using the borate extraction-CBQCA assay was positively correlated with contents determined using a bicarbonate-total amino acid analysis method. Oil refining substantially reduced the oil protein content determined by the borate-CBQCA assay with neutralized/refined, bleached, and deodorized (fully refined) oils containing 62-265 ng/g oil, whereas crude un-degummed oils contained 86000-87900 ng/g of protein. These analyses and published data on cumulative threshold doses for soybean suggest that even the most sensitive individuals would need to consume at least 50 g of highly refined oil to experience subjective symptoms.

A Review of Food Allergy and Nutritional Considerations in the Food-Allergic Adult

In the United States, the prevalence of adults with food allergies is approximately 2% to 3%. Theoretically, any food can cause an allergic reaction; however, some foods are clearly more allergenic than others. In adults, peanuts, tree nuts, finned fish, crustaceans, fruit, and vegetables account for 85% of the food-allergic reactions. Currently, the only ways to manage food allergies are to avoid the allergen and initiate therapy for an allergic reaction if ingestion does occur. The presence of homologous proteins among animal or plant foods and between foods and certain airborne allergens may account for cross-sensitization that may be clinically relevant. For inpatients or outpatients with food allergies, nutrient and fluid requirements are the same as for individuals without food allergies. Since patients with adverse reactions to food may self-restrict intake or have been counseled on food avoidance, it is particularly important to determine dietary adequacy and to provide patients with appropriate food substitutions to provide nutrients that may be missing from a patient’s diet. This is of particular concern for individuals with multiple food allergies. Eating away from home and traveling also pose special problems for those with food allergies.

Determination of proteins in refined and nonrefined oils

Five methods using aqueous/organic solvents for the separation of proteins from oils were compared. The extraction with acetone-hexane followed by amino acid analysis was found to be the most suitable method for isolation and quantification of proteins from oils. The detection limit of the method was 0.18 mg protein/kg oil, and the quantification limit was 0.6 mg protein/kg. The relative repeatability limit for samples containing 1-5 mg protein/kg sample was 27%. The protein recovery ranged between 68 and 133%. Using this method, the protein content of 14 refined and nonrefined oils was determined. In none of the refined oils were proteins detected, whereas the protein content of the unrefined oils ranged between undetectable in extra virgin olive oil to 11 mg/kg in rapeseed oil. With sodium dodecyl sulfate-polyacrylamide gel electrophoresis in combination with silver staining, many protein bands were visible in the unrefined soy, olive, peanut, and rapeseed oil samples. Proteins bands were not obtained from the refined fish oil. In the other refined oil samples, a few proteins bands could be visualized. Two protein bands with apparent molecular molecular masses of 58 and 64 kDa were always observed in these oils.

Allergenicity of soybean: new developments in identification of allergenic proteins, cross-reactivities and hypoallergenization technologies

Soybean is considered one of the "big eight" foods that are believed to be responsible for 90% of all allergenic reactions. Soy allergy is of particular importance, because soybeans are widely used in processed foods and, therefore, represent a particularly insidious source of hidden allergens. Although significant advances have been made in the identification and characterization of soybean allergens, scientists are not completely certain about which proteins in soy cause allergic reactions. At least 16 allergens have been identified. Most of them, as with other plant food allergens, have a metabolic, storage, or protective function. These allergens belong to protein families which have conserved structural features in relation with their biological activity, which explains the wide immunochemical cross-recognition observed among members of the legume family. Detailed analysis of the structure-allergenicity relationships has been hampered by the complexity and heterogeneity of soybean proteins. A variety of technological approaches have been attempted to decrease soybean allergenicity. This paper provides a comprehensive review of the current body of knowledge on the identification and characterization of soybean allergens, as well as an update on current hypoallergenization techniques.

Allergenic potency of spices: hot, medium hot, or very hot

Spices are the most attractive ingredients to confer an authentic taste to food. As they are derived from plants, they harbour allergenic potency and can induce symptoms ranging from mild local to severe systemic reactions. Due to the content of pharmacologically active substances of spices, the diagnosis of allergy and the differentiation from intolerance reactions may be difficult. Association with inhalative allergies via IgE cross-reactivity, but also direct gastrointestinal sensitization plays a role. This article is a botanical and allergological overview of the most important spices and molecules responsible for eliciting IgE-mediated reactions or cross-reactions. As no curative treatments are known at present, strict avoidance is recommended and, therefore, accurate labelling of pre-packed food is necessary.

Update on threshold doses of food allergens: implications for patients and the food industry

PURPOSE OF REVIEW

The purpose of this review is to bring the reader up to date on the importance of assessing a food's lowest observed adverse-effect level (LOAEL) with two aims. Firstly, to help industry choose tests with a level of sensitivity capable of detecting food allergens hidden in industrial products. Secondly, to specify protective measures for highly allergic individuals in order to prevent recurrent severe anaphylaxis. The review also seeks to highlight the present issues and unsolved questions.

RECENT FINDINGS

Thanks to standardized oral-provocation tests (double-blind placebo-controlled food challenges), LOAELs have been identified for many IgE-dependent food allergies. Most studies concern the pediatric population. Data is available for milk, egg, peanut, wheat flour, and sesame. The LOAELs are commonly in the range of 1-2 mg of natural foods, representing a few hundred micrograms of protein. These minimal reactive doses characterize about 1% of people allergic to milk, egg, or peanut. The level at which no observed adverse effect is seen might be a few tens of micrograms of protein for peanut. At the present time, allergy to oil seems to be restricted to unrefined cold-pressed oils.

SUMMARY

Concerning IgE-dependent food allergies, the threshold dose inducing symptoms is now known to vary a great deal according to the individual. A reactive dose of less than 65 mg characterizes 16 and 18% of patients allergic to egg or peanut. Less than 30 mg of milk proteins characterizes 5% of those allergic to milk. For milk, egg, and peanut, 1% of patients have a very low threshold, about 1 mg. Such data emphasize the necessity of using detection tests with a sensitivity better than 10 parts per million. The modifications of allergenicity undergone by protein ingredients that are now commonly introduced into industrially made products are not yet sufficiently known. A better knowledge of the reactive doses of these proteins is needed.

Thresholds of clinical reactivity to milk, egg, peanut and sesame in immunoglobulin E-dependent allergies: evaluation by double-blind or single-blind placebo-controlled oral challenges

BACKGROUND

The prevalence of food anaphylaxis due to masked allergens has increased within the last 10 years. Contamination of manufactured products by food allergens is a key concern for food industries.

OBJECTIVE

To determine quantities eliciting reactions in patients who have an IgE-dependent food allergy, thanks to standardized oral provocation tests. To evaluate the subsequent levels of sensitivity required for the detection tests of allergens for egg, peanut, milk and sesame.

METHODS

Prick-in-prick tests, Cap system RAST, and single or double-blind placebo-controlled food challenges (SBPCFC or DBPCFC) were performed. The doses of natural food were gradually increased from 5 to 5000 mg for solid food and from 1 to 30 mL for peanut oil, sunflower oil, soy oil and sesame oil.

RESULTS

Data from 125 positive oral challenges to egg, 103 to peanut, 59 to milk and 12 to sesame seeds were analysed. Haemodynamic modifications were observed in 2%, 3%, 1.7%, and 8% of the oral challenges (OCs) to egg, peanut, milk and sesame, respectively. Respiratory symptoms were observed in 12%, 20%, 10% and 42% of egg, peanut milk and sesame allergies, respectively. A cumulative reactive dose inferior or equal to 65 mg of solid food or 0.8 mL of milk characterized 16%, 18%, 5% and 8% of egg, peanut, milk and sesame allergies, respectively. 0.8% of egg allergies, 3.9% of peanut allergies, and 1.7% of milk allergies reacted to 10 mg or less of solid food or to 0.1 mL for milk. The lowest reactive threshold has been observed at less than 2 mg of egg; 5 mg of peanut, 0.1 mL of milk and 30 mg of sesame seed. Ten out of 29 OC with peanut oil, two out of two OC with soy oil and three out of six OC with sunflower oil were positive. Five out six OC with sesame oil were positive: 1 and 5 mL induced an anaphylactic shock.

CONCLUSION

The risk of asthma and anaphylactic shock to sesame and peanut is confirmed. Minimal reactive quantities show that, in order to guarantee a 95% safety for patients who are allergic to egg, peanut and milk, and on the basis of consumption of 100 g of food, the detection tests should ensure a sensitivity of 10 p.p.m. for egg, 24 p.p.m. for peanut and 30 p.p.m. for milk proteins. Oil allergies being considered, the limit of sensitivity should fall to 5 p.p.m.