Food Allergies in Children - Allergy,Nutrition：兒童過(guò)敏的食物過(guò)敏營(yíng)養(yǎng)

1、Infant Food AllergiesWhere Are We Now?Janice Joneja Ph.D., RD2Food Allergy in the Past 7 YearsNearly 4% of North Americans have food allergies, many more than recorded in the pastIncidence of food allergy much higher in children (8%) than adults (4 years of age underwent SOTIStarting dose 0.05 ml co

2、ws milkIncreased to 1 ml on first dayIncreasing dosage weekly up to a daily dose of 200-250 mlResults: 16/18 tolerated 200-250 ml milkLength of process median 14 weeks (range 11-17 weeks)Tolerance has been maintained for 1 year_Zapatero et al 20084142Oral Tolerance Induction to Milk, Egg, and Peanut

3、36% of children with IgE-mediated allergy to cows milk and hens egg developed permanent tolerance of the foods after a median 21 months specific oral tolerance induction (SOTI)1 4 peanut-allergic children underwent SOTI:Daily doses of peanut flour starting at 5 mg peanut protein2-weekly dosage incre

4、ase up to 800 mg proteinAll subjects tolerated at least 10 whole peanuts (2.38 g protein) on post-intervention challenge2_1Staden et al 2007_2Clark et al 20094243Progression of Peanut AllergyPeanut allergy, like many early food allergies, can be outgrownIn 2001 pediatric allergists in the U.S. repor

5、ted that about 21.5 per cent of children will eventually outgrow their peanut allergy1Those with a mild peanut allergy, as determined by the level of peanut-specific IgE in their blood, have a 50% chance of outgrowing the allergy2Only about 9% of patients are reported to outgrow their allergy to tre

6、e nuts3_1Skolnick et al 20012Fleischer et al 20033Fleischer et al 20054344Maintaining Tolerance of PeanutWhen there is no longer any evidence of symptoms developing after a child has consumed peanuts, it is preferable for that child to eat peanuts regularly, rather than avoid them, in order to maint

7、ain tolerance to the peanutChildren who outgrow peanut allergy are at risk for recurrence, but the risk has been shown to be significantly higher for those who continue to avoid peanuts after resolution of their symptoms _Fleischer et al 20044445Probiotics and Allergy PreventionProbiotics and prebio

8、tics may change the colonic microflora of the neonateTheory: Change from Th2 to Th1 response in the neonatal period is required to reduce potential for allergyThis change is mediated by contact with micro-organismsNon-allergic children have a predominance of lactobacilli and bifidobacteriaAtopic chi

9、ldren tend to have more clostridia and lower levels of bifidobacteriaProbiotics could be used to change the “atopic” to a more “non-atopic flora”_Ozdemir 201046Studies on Probiotics in Allergy PreventionSome studies indicate a positive outcome in reducing the incidence of allergy:Lactobacillus F19 i

10、n cereals fed to infants from 4 to 13 months of age reduced the incidence of eczema1 Other studies showed no effect:Bifidobacterium + Lactobacillus rhamnosus daily for the first 6 months in at risk infants had no effect compared to placebo2_1 West et al 2009_2 Soh et al 200947Current Status of Probi

11、otics in Allergy PreventionBeneficial effects of probiotic therapy depends on:Type of bacteria selectedDosage of the bacteria delivered to the digestive tractMethod of delivery of the bacteria to the GI tract (in formulae; in cereals)Age of the individualLength of duration of deliveryConclusion at t

12、he current state of research:Probiotics cannot be recommended generally for primary prevention of atopic disease_Ozdemir 2010a48Take Home MessageAllergy prevention emphasizes inducing tolerance rather than avoiding sensitizationBeginning of tolerance to foods may occur in utero or during breast-feed

13、ingRestriction of maternal diet to avoid highly allergenic foods during pregnancy or lactation is contraindicatedUnless either mother or baby is allergic to them49Take Home MessageManagement of established food allergy includes: Accurate identification of the allergenic food(s)Careful avoidance of t

14、he food allergens especially if there is any risk of anaphylaxisAvoidance of unnecessary food restrictions50Take Home MessageProvision of complete balanced nutrition by substituting foods of equal nutritional valueMonitoring the childs response at intervals to determine when the food allergy has been outgrownMainte