Tragacanth gum
Clinical Relevance
IgE-mediated reactions
Tragacanth gum may rarely induce allergy symptoms in sensitised individuals. Asthma and contact dermatitis have been described.
Excess ingestion can result in diarrhoea, abdominal pain, gas production or constipation.
Other reactions
Many members of this genus contain toxic glycosides. All species with edible seedpods can be distinguished by their fleshy round or oval seedpod that looks somewhat like a Greengage. A number of species can also accumulate toxic levels of selenium when grown in soils that are relatively rich in that element.
Cross-Reactivity
An extensive cross-reactivity among the different individual species of the genus could be expected but in fact is not seen frequently. In an in vitro study, the specific IgE binding by protein extracts of 11 food legumes was examined by RAST and RAST inhibition. Cross-allergenicity was demonstrated to be most marked among the extracts of Peanut, Garden pea, Chick pea, and Soybean.
However, clinical studies have found that there is little cross-reactivity among members of the Fabaceae (Leguminosae).
Cross-reactivity between Acacia gum and Tragacanth gum has been reported.
References
- Brown EB, Crepea SB. Allergy (asthma) to ingested gum tragacanth. J Allergy 1947;18:214-216
- Gelfand, HH. Allergenic properties of the vegetable gums. J Allergy 1943;14:203-219
- Yeates H, Jenson, K, Orem, UT. Chronic anaphylaxis caused by ingestion of vegetable gum products. J Allergy Clin Immunol 1991;87(Suppl 1 Pt 2):274.
- Yman L, Rolfsen, W, Malmheden Yman, I. Food additives from the legume family (Leguminosae/Fabaceae): A potential allergy risk. Allergy 1988;81:H-17/81
- Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09
- Barnett D, Bonham B, Howden ME. Allergenic cross-reactions among legume foods--an in vitro study. J Allergy Clin Immunol 1987;79(3):433-8
- Bardare M, Magnolfi C, Zani G. Soy sensitivity: personal observation on 71 children with food intolerance. Allerg Immunol (Paris) 1988;20(2):63-6
- Bernhisel Broadbent J, Sampson HA. Cross-allergenicity in the legume botanical family in children with food hypersensitivity. J Allergy Clin Immunol 1989;83:435-440
- Bernhisel-Broadbent J, Taylor S, Sampson HA. Cross-allergenicity in the legume botanical family in children with food hypersensitivity. II. Laboratory correlates. J Allergy Clin Immunol 1989;84(5 Pt 1):701-9
- Eigenmann PA, Burks AW, Bannon GA, Sampson HA. Identification of unique peanut and soy allergens in sera adsorbed with cross-reacting antibodies. J Allergy Clin Immunol 1996;98(5 Pt 1):969-78
- Raghuprasad PK, Brooks SM, Litwin A, Edwards JJ, Bernstein IL, Gallagher J. Quillaja bark (soapbark)--induced asthma. J Allergy Clin Immunol 1980;65(4):285-7