Food Allergies: What are they and can we prevent them?
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Food Allergies: What are they and can we prevent them?

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  • 2-8% in young children, only 2% in adults
  • For example, only 7% of parents were able to identify milk protein in all 14 sample labels (Joshi et al, 2003)
  • Breastfeeding - (preventative until 18 months for CMA) Solids - reduces incidence of CMA and eczema

Food Allergies: What are they and can we prevent them? Food Allergies: What are they and can we prevent them? Presentation Transcript

  • Food Allergies What are they and can we prevent them? Heather Mileski, RD Pediatric Gastroenterology and Nutrition, MCH
  • Outline
    • Define allergy
    • Differentiate between types of allergies
    • Discuss diagnostic tools available
    • Treatment
    • Consider preventative measures
  • What is the incidence of food allergy in young children?
    • <10%
    • 10-20%
    • 20-30%
    • >30%
    Garcia-Careaga, 2005
  • Definitions
    • Allergy – “a pathological immune reaction to a food protein”
    • Adverse food reaction – “an ill effect as a result of the intake of food”
        • Intolerances, sensitivities, enzyme deficiency (e.g. galactosemia, disaccharidase, etc), pharmacological effect (e.g. food dyes, preservatives, MSG, caffeine, etc)
  • Type 1: IgE-mediated (immune)
    • Immediate Hypersensitivity Disorder
      • Symptoms occur in minutes to hours
      • Can become anaphylactic
      • Common triggers are milk, soy, egg, peanut, shellfish, wheat
      • 80% resolve after several years with the exception of peanut and shellfish
    Garcia-Careaga et al, 2005
  •  
  • Type 1: IgE-mediated
    • Oral Allergy Syndrome/Pollen-Food Allergy Syndrome
      • Symptoms occur in minutes to hours
      • Reaction limited to oral cavity
      • Rarely systemic symptoms
      • Common triggers are RAW fruit and vegetables
      • Cross-reaction with airborne allergens
  • Oral Allergy Syndrome Tomatoes Grass pollen Melons (includes cucumbers) and bananas Ragweed Apples, pears, celery, hazelnuts, kiwi, potatoes, carrots Birch Food Allergen Airborne Allergen
  • Type III and IV: Non-Immune Mediated
    • Proctocolitis (Cow’s Milk Protein Colitis)
      • Occurs in infancy resolves between 6 months-2 years
    • Dietary Food Enteropathy
      • Occurs in infancy, usually resolves in first 2 years of life
  • Mixed IgE and Non-IgE
    • Eosinophilic Gastroenteritis
      • Eosinophilic infiltration of esophagus, stomach and small bowel mucosa
    • Eosinophilic Esophagitis
    • Both conditions diagnosed by biopsy
  • Other Adverse Food Reactions
    • Lactose Intolerance
      • Reaction to milk sugar NOT protein
    • Dietary Fructose Intolerance
      • Reaction to the sugar fructose
    • Food Sensitivities e.g. gluten
  • Conventional Diagnostic Tools
    • IgE-Mediated
    • Skin prick testing
    • RAST– blood test
    • Double-blind placebo control challenge
    • Non-IgE
    • Stool samples for blood, pus cells
    • Endoscopy with biopsy
    • Elimination diets
  • Alternative Diagnostic Tools Herman and Drost, 2004 Measures enzyme defects or deficiencies via a blood sample placed in electric current Carroll Testing Measures electro-magnetic pulses through the body Vega Testing Muscle strength testing Kinesiology Saliva sample sIgA ELISA Serum sample IgG ELISA (variety of specific tests e.g. IgG4) Testing Technique Name of Test
  • Treatment
    • Avoidance
      • IgE-mediated allergies require strict avoidance of the allergen
      • Adverse food rxns are dose-dependent
    • Education
      • Children and parents need detailed education on label reading
  • Which of the following is NOT a milk protein?
    • Casein
    • Lecithin
    • Whey
  • Is Prevention Possible?
    • No evidence for prevention in general population
    • Some evidence in high risk infants
      • High risk = first degree relative with atopy (eczema, food allergy, asthma, allergic rhinitis)
  • Prevention Guidelines – AAP Only for High Risk Infants
    • 2000
    • Pregnancy possibly restrict peanut
    • Exclusive breastfeeding for 6 months
    • Eliminate peanuts & nuts from lactation diet (consider eggs, cow’s milk, fish)
    • If bottle-fed use hypoallergenic formula (extensive of partial hydrolysate)
    • Solids at 6 mo; cow’s milk at 12 mo; eggs at 24 mo; peanuts, nuts and fish at 36 mo
  • Prevention Guidelines 2004 Euro Academy of Allerg and Clin Immunol
    • Breastfeed exclusively for 4 months
    • If bottle-fed use extensively hydrolyzed formula
    • Solids at 4 to 6 months
    • Additional studies required to demonstrate any preventive effects of further dietary restriction
  • Prevention Guidelines – AAP Only for High Risk Infants
    • 2008
    • No dietary restrictions during pregnancy or lactation
    • Exclusive breastfeeding for 6 months
    • If bottle-fed use extensively hydrolyzed formulas
    • Solids at 4 to 6 months, no evidence to support delayed introduction of foods considered to be allergenic
  • Is Waiting Better?
    • Israeli population and peanuts
    • Swedish population and fish
    • German GINI study
  • Take Home Messages
    • Encourage exclusive breastfeeding for 6 months (WHO guidelines)
    • If bottle-feeding use extensively hydrolyzed formula if high risk infant
    • Avoid introduction of solid foods until 4-6 months of age
    • Stay tuned, this isn’t the end of the story!
  • References
    • Garcia-Careaga et al. Gastrointestinal Manifestations of Food Allergies in Pediatric Patients. Nutr in Clin Prac 20:526-535, 2005.
    • Herman, P & Drost, L. Evaluating the Clinical Relevance of Food Sensitivity Tests: A Single-Subject Experiment. Alt Med Review 9(2):198-207.
    • Joneja, J. Food Allergy in Adults. Dietitians of Canada Current Issues, 2007.
    • Joshi et al. Interpretation of Commercial Food Ingredient Labels by Parents of Food-Allergic Children. Ann Allergy Asthma Immunol 90:84-89, 2003.
    • Muraro et al. Dietary Prevention of Allergic Diseases in Infants and Small Children. Pediatr Allergy Immunol 15:291-307, 2004.
    • Pyrhonen et al. Occurrence of parent-reported food hypersensitivities and food allergies among children aged 1-4 yr. Pediatr Allergy Immunol 20:328-338, 2009.
    • Wennergren, G. What if it is the other way around? Early introduction of peanut and fish seems to be better than avoidance. Acta Paediatrica 98:1085-1087, 2009.