Tolerance of soya lecithin in children with non-immunoglobulin E-mediated soya allergy: a randomised, double-blind, cross-over trial

Background Soya lecithin is present in a wide variety of foods regularly consumed by children, in the form of an emulsifier or stabiliser. Children with non-immunoglobulin (Ig)E-mediated allergies who commonly have to avoid milk and soya will have a significantly restrictive diet with reduced alternative foods if soya lecithin also has to be eliminated. The present study aimed to establish whether children with non-IgE-mediated gastrointestinal soya allergy react to soya lecithin in food products. Methods A double-blind, cross-over study was performed in soya-allergic children aged between 8 months and 5 years. Eligible children had their soya allergy status confirmed with a home challenge. Children were randomly assigned to either placebo or challenge dose of soya lecithin (1.5 g per day) in a custom-made biscuit. This was followed by a 1-week washout period and cross-over to another 1 week of challenge or placebo dose. Symptoms were recorded prior to commencing the study and at the end of each week's challenge. Results Twenty-two children, 16 boys, with a median age of 44 months (range 21-58 months) were recruited, although only 20 completed the full study. The median number of foods avoided in addition to soya was 3. Over the challenge period, the parents reported reactions in six cases: five cases (23%) to the placebo and one case (5%) to the challenge dose. There was no statistical difference (P = 0.025) between the groups. Conclusions One child with a non-IgE-mediated gastrointestinal allergy had a slight reaction to soya lecithin. Although single cases may react to soya lecithin, we suggest that soya lecithin should be included in children with this delayed allergy, unless they have a confirmed reaction to traces of soya within this emulsifier.