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?

    1. 1. Food Allergies What are they and can we prevent them? Heather Mileski, RD Pediatric Gastroenterology and Nutrition, MCH
    2. 2. Outline <ul><li>Define allergy </li></ul><ul><li>Differentiate between types of allergies </li></ul><ul><li>Discuss diagnostic tools available </li></ul><ul><li>Treatment </li></ul><ul><li>Consider preventative measures </li></ul>
    3. 3. What is the incidence of food allergy in young children? <ul><li><10% </li></ul><ul><li>10-20% </li></ul><ul><li>20-30% </li></ul><ul><li>>30% </li></ul>Garcia-Careaga, 2005
    4. 4. Definitions <ul><li>Allergy – “a pathological immune reaction to a food protein” </li></ul><ul><li>Adverse food reaction – “an ill effect as a result of the intake of food” </li></ul><ul><ul><ul><li>Intolerances, sensitivities, enzyme deficiency (e.g. galactosemia, disaccharidase, etc), pharmacological effect (e.g. food dyes, preservatives, MSG, caffeine, etc) </li></ul></ul></ul>
    5. 5. Type 1: IgE-mediated (immune) <ul><li>Immediate Hypersensitivity Disorder </li></ul><ul><ul><li>Symptoms occur in minutes to hours </li></ul></ul><ul><ul><li>Can become anaphylactic </li></ul></ul><ul><ul><li>Common triggers are milk, soy, egg, peanut, shellfish, wheat </li></ul></ul><ul><ul><li>80% resolve after several years with the exception of peanut and shellfish </li></ul></ul>Garcia-Careaga et al, 2005
    6. 7. Type 1: IgE-mediated <ul><li>Oral Allergy Syndrome/Pollen-Food Allergy Syndrome </li></ul><ul><ul><li>Symptoms occur in minutes to hours </li></ul></ul><ul><ul><li>Reaction limited to oral cavity </li></ul></ul><ul><ul><li>Rarely systemic symptoms </li></ul></ul><ul><ul><li>Common triggers are RAW fruit and vegetables </li></ul></ul><ul><ul><li>Cross-reaction with airborne allergens </li></ul></ul>
    7. 8. Oral Allergy Syndrome Tomatoes Grass pollen Melons (includes cucumbers) and bananas Ragweed Apples, pears, celery, hazelnuts, kiwi, potatoes, carrots Birch Food Allergen Airborne Allergen
    8. 9. Type III and IV: Non-Immune Mediated <ul><li>Proctocolitis (Cow’s Milk Protein Colitis) </li></ul><ul><ul><li>Occurs in infancy resolves between 6 months-2 years </li></ul></ul><ul><li>Dietary Food Enteropathy </li></ul><ul><ul><li>Occurs in infancy, usually resolves in first 2 years of life </li></ul></ul>
    9. 10. Mixed IgE and Non-IgE <ul><li>Eosinophilic Gastroenteritis </li></ul><ul><ul><li>Eosinophilic infiltration of esophagus, stomach and small bowel mucosa </li></ul></ul><ul><li>Eosinophilic Esophagitis </li></ul><ul><li>Both conditions diagnosed by biopsy </li></ul>
    10. 11. Other Adverse Food Reactions <ul><li>Lactose Intolerance </li></ul><ul><ul><li>Reaction to milk sugar NOT protein </li></ul></ul><ul><li>Dietary Fructose Intolerance </li></ul><ul><ul><li>Reaction to the sugar fructose </li></ul></ul><ul><li>Food Sensitivities e.g. gluten </li></ul>
    11. 12. Conventional Diagnostic Tools <ul><li>IgE-Mediated </li></ul><ul><li>Skin prick testing </li></ul><ul><li>RAST– blood test </li></ul><ul><li>Double-blind placebo control challenge </li></ul><ul><li>Non-IgE </li></ul><ul><li>Stool samples for blood, pus cells </li></ul><ul><li>Endoscopy with biopsy </li></ul><ul><li>Elimination diets </li></ul>
    12. 13. 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
    13. 14. Treatment <ul><li>Avoidance </li></ul><ul><ul><li>IgE-mediated allergies require strict avoidance of the allergen </li></ul></ul><ul><ul><li>Adverse food rxns are dose-dependent </li></ul></ul><ul><li>Education </li></ul><ul><ul><li>Children and parents need detailed education on label reading </li></ul></ul>
    14. 15. Which of the following is NOT a milk protein? <ul><li>Casein </li></ul><ul><li>Lecithin </li></ul><ul><li>Whey </li></ul>
    15. 16. Is Prevention Possible? <ul><li>No evidence for prevention in general population </li></ul><ul><li>Some evidence in high risk infants </li></ul><ul><ul><li>High risk = first degree relative with atopy (eczema, food allergy, asthma, allergic rhinitis) </li></ul></ul>
    16. 17. Prevention Guidelines – AAP Only for High Risk Infants <ul><li>2000 </li></ul><ul><li>Pregnancy possibly restrict peanut </li></ul><ul><li>Exclusive breastfeeding for 6 months </li></ul><ul><li>Eliminate peanuts & nuts from lactation diet (consider eggs, cow’s milk, fish) </li></ul><ul><li>If bottle-fed use hypoallergenic formula (extensive of partial hydrolysate) </li></ul><ul><li>Solids at 6 mo; cow’s milk at 12 mo; eggs at 24 mo; peanuts, nuts and fish at 36 mo </li></ul>
    17. 18. Prevention Guidelines 2004 Euro Academy of Allerg and Clin Immunol <ul><li>Breastfeed exclusively for 4 months </li></ul><ul><li>If bottle-fed use extensively hydrolyzed formula </li></ul><ul><li>Solids at 4 to 6 months </li></ul><ul><li>Additional studies required to demonstrate any preventive effects of further dietary restriction </li></ul>
    18. 19. Prevention Guidelines – AAP Only for High Risk Infants <ul><li>2008 </li></ul><ul><li>No dietary restrictions during pregnancy or lactation </li></ul><ul><li>Exclusive breastfeeding for 6 months </li></ul><ul><li>If bottle-fed use extensively hydrolyzed formulas </li></ul><ul><li>Solids at 4 to 6 months, no evidence to support delayed introduction of foods considered to be allergenic </li></ul>
    19. 20. Is Waiting Better? <ul><li>Israeli population and peanuts </li></ul><ul><li>Swedish population and fish </li></ul><ul><li>German GINI study </li></ul>
    20. 21. Take Home Messages <ul><li>Encourage exclusive breastfeeding for 6 months (WHO guidelines) </li></ul><ul><li>If bottle-feeding use extensively hydrolyzed formula if high risk infant </li></ul><ul><li>Avoid introduction of solid foods until 4-6 months of age </li></ul><ul><li>Stay tuned, this isn’t the end of the story! </li></ul>
    21. 22. References <ul><li>Garcia-Careaga et al. Gastrointestinal Manifestations of Food Allergies in Pediatric Patients. Nutr in Clin Prac 20:526-535, 2005. </li></ul><ul><li>Herman, P & Drost, L. Evaluating the Clinical Relevance of Food Sensitivity Tests: A Single-Subject Experiment. Alt Med Review 9(2):198-207. </li></ul><ul><li>Joneja, J. Food Allergy in Adults. Dietitians of Canada Current Issues, 2007. </li></ul><ul><li>Joshi et al. Interpretation of Commercial Food Ingredient Labels by Parents of Food-Allergic Children. Ann Allergy Asthma Immunol 90:84-89, 2003. </li></ul><ul><li>Muraro et al. Dietary Prevention of Allergic Diseases in Infants and Small Children. Pediatr Allergy Immunol 15:291-307, 2004. </li></ul><ul><li>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. </li></ul><ul><li>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. </li></ul>

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