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Allergy to Soy Lecithin in a Child

1996; Lippincott Williams & Wilkins; Volume: 22; Issue: 3 Linguagem: Inglês

10.1097/00005176-199604000-00019

1536-4801

Catherine Renaud, Catherine Cardiet, Christophe Dupont,

Analytical Methods in Pharmaceuticals

Allergy to native peanut protein components was recently demonstrated to be responsible for sensitization via oral ingestion of peanut oil, leading to the recommendation of total avoidance of such oil in the preparation of infant formula fat blends (1). Soy lecithin is another widely used fat component of industrial food, especially in the composition of several extensively hydrolyzed infant formulas recommended for use in children with cow's milk allergy (CMA). We report a case in which soy lecithin appeared to trigger adverse effects, demonstrated via double-blind placebo-controlled food challenge (DBPCFC) and intestinal permeability tests (IPTs). CASE REPORT A 3-year-old boy presented with weight retardation related to chronic diarrhea and associated with abdominal pain and postprandial emesis. A careful clinical history indicated that symptoms were triggered by different candies and deep-frozen foods. Clinical history indicated CMA in a sister and personal recurrent bronchitis in the patient. The child was breast-fed during the first 4 months of life and then fed a normal diet. Clinical examination revealed a distended abdomen, but no abnormalities were found in blood electrolytes and hepatic parameters. Stool evaluation for virus and bacteria was negative. Upper digestive fibroscopy was normal, including a small intestine mucosal sample. Skin-prick tests were positive for soy but negative for other foods. There was an increased total IgE blood level (64 KUI/L) but a negative RAST Fx5 (Kabi Pharmacia, Sweden). A soy-free diet was started, leading to a significant improvement of clinical symptoms except for a vomiting episode following ingestion of a candy containing soy lecithin. The diet was tightened by eliminating all food with soy lecithin, and the child became symptom-free. A DBPCFC was carried out 6 months later, according to the usual recommendations (2), together with IPTs as previously described (3). Native soy lecithin (The Lecithin People, MC-THIN AF1, Lucas Meyer) triggered a 1-week diarrheal bout, whereas placebo had no effect. During provocation with soy lecithin, the urinary lactulose/mannitol ratio exhibited a sharp rise as compared to a fasting test (4.25% versus 1.34%), indicating an alteration of intestinal permeability. During provocation with placebo, no significant modification was observed (1.82% versus 1.59%). The protein content of soy lecithin as measured by a catharometric analyzer (EAS 1690 Carlo Erba Science) was 4.31 g/100 g. DISCUSSION The recent demonstration of the immunogenicity of early exposure to peanut oil (1) has led to a wide questioning of the actual consequences of the presence in dietary fats of trace amounts of proteins known to bear an allergenic potential. Four major protein fractions in soybean are implicated as causing soy allergic reactions (4). Even though allergies to soy lecithin are not yet well documented, the latter is known to contain higher concentrations of proteins than does soy oil (5), as documented in the present case. Soy lecithin allergy was suspected on adverse reactions to candies and was proven through DBPCFC and IPTs. DBPCFC is considered the gold standard in food allergy (2). IPTs, already shown to demonstrate the alterations induced by hidden allergens such as in breast milk (3), yielded similar results. In view of the known association of adverse reactions between soy and cow's milk proteins (leading to soy avoidance in at least 35% of children with CMA), the presence of soy lecithin in several extensively hydrolyzed infant formulas (Alfare, 1 g/100 g powder; Galliagène, 0.9%; Peptijunior, 0.56%) may be relevant to sometimes ineffective elimination diets in children with CMA. Even though there is little information at present on the quantities of ingested soy allergen that pose risks to soy-sensitive subjects, our data demonstrate that hidden allergens contained in soy lecithin can induce adverse effects in soy allergic children. Acknowledgment: We acknowledge the collaboration of J. G. Gobert (Hôpital Bichat-Claude Bernard, Paris), who performed the protein assay in soy lecithin.