Royal Prince Alfred Hospital Royal Prince Alfred Hospital
Allergy Unit

Student research


Maternal Dietary Modification for Prevention of Food Sensitisation

by
Ting (Chloe) Liang
Master of Science (Nutrition and Dietetics), University of Wollongong
Supervisors: Anne Swain, Velencia Soutter, Robert Loblay
October 2007

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Abstract

Introduction: Peanut and egg are the most common food allergies in Australia and may cause life threatening allergic reactions, anaphylaxis1. Since 1994, RPAH Allergy Unit has been advising maternal dietary modification (mainly peanut and tree nuts avoidance) during pregnancy in high-risk families to prevent children developing a food allergy. This study aims to investigate the effectiveness of this advice.

Methods: Families with children (N=2114) with previously diagnosed food allergy were selected. Siblings of the index children were divided according to whether their mothers had avoided egg or peanut during late pregnancy and lactation. Siblings underwent skin prick tested for the common food allergens. Sensitization was defined as a SPT greater than 3x3mm. Results of egg and peanut SPT were analysed in those aged <1yr, 1-2 yrs, 2-4 yrs and >4yrs. Chi square tests were used for significance (p<0.05).

Results: Among the four age groups, there was no significant difference in the prevalence of egg sensitization whether the diet was modified or not. However, there was a significant difference in prevalence of peanut sensitization depending on whether peanut avoidance measures were adopted. The effect was much greater in the first year (p=0.02) and remained significant in most of the subsequent years. There was no significant difference in sensitization to other foods in relation to peanut avoidance.

Discussion: Although avoidance advice had no significant effect on egg sensitisation, maternal peanut avoidance measures significantly reduced the incidence of peanut sensitization, especially in the first year of life. The diminishing benefit of peanut avoidance measures after the first year of life suggests that subsequent sensitisation to peanut may be occuring through subtle environmental or dietary exposure.

Reference: 1. Bock SA, Furlong AM, Sampson Hugh, Fatalities due to anaphylactic reactions to foods. J Allergy Clin Immunol 2001; 107: 191-3.