A Preschool Nutrition Primer for RDs

Food Allergies and Intolerances

Nutrition Screening Tool for Every Preschooler

Évaluation de l’alimentation des enfants d’âge préscolaire

Learning Objectives

Distinguish food allergy from other adverse food reactions.List the nine common food allergens according to Health Canada.Understand medical diagnosis and management of food allergy (including symptoms and tests) in order to communicate effectively with the client and attending physician.Understand the appropriate dietary management of food allergy, including allergen avoidance and ensuring nutritional adequacy.List high-risk situations for allergic individuals.List strategies for avoiding allergenic proteins in foods.

Presentation Outline

Introduction to Food AllergiesAllergy versus IntoleranceThe Immune SystemReactions to an AllergenDiagnosis of a Food AllergyManaging Food AllergiesPrevention/Delaying Allergic DiseaseHealth Canada Regulations on Allergen Food LabelingPractice QuestionsReferences

Introduction to Food Allergies

Also known as hypersensitivity.Immune system response to the protein in foods.Body recognizes protein as a foreign substance and produces a number of responses (allergic reactions).Reaction is not dose dependent.Common food allergies in children: eggs, soy, milk, wheat, seafood (shellfish,fish), peanuts, tree nuts, and sesame (sulphites).Common food allergies in adults: peanuts, tree nuts, shellfish, and fish.

Statistics of Food Allergies

Nearly 4% of North Americans have food allergies, many more than recorded in the past.

Incidence of food allergy much higher in children (>8%) than adults (<2%).

Prevalence of some food allergies doubled in American children younger than 5 years of age in the past 5 years.Many food allergens have been characterized at the molecular level, leading to increased understanding of the causes of many allergic disorders.

Incidence of Food Allergy

Prevalence highest in infants and toddlers. Cow’s milk allergy incidence: 2.5% of infants.Up to 8% of children under 3 years have allergy to a limited number of foods:

Cow’s milkWheat EggShellfishFishSoyPeanutTree nuts

Incidence of Food Allergy

Over 170 foods have been documented as causing food allergy. 90% of food allergies in children are due to:- Milk - Soy - Peanut- Egg - Wheat

85% of food allergies in adolescents and adults are due to:- Peanut - Fish- Tree nuts - Shellfish

Priority Food Allergens in Canada

Peanuts Tree nuts (almonds, brazil nuts, cashews, hazelnuts (filberts), macadamia nuts, pecans, pinenuts, pistachios, walnuts).Sesame seedsMilkEggsFishShellfish (e.g. clams, mussels, oysters, scallops and crustaceans such as crab, crayfish, lobster, shrimp).SoyWheatSulphites

These Priority Allergens account for more than 95% of severe adverse reactions related to food allergens.

Allergy versus Intolerance

Food Allergy Food IntoleranceAn immune response to an ingested

food or food additive that contains a protein or a molecule linked to a protein

Reaction is not dose-dependent

Requires a “sensitizing event” that primes the immune system for future response

Allergic potential is an inherited characteristic (is idiosyncratic)

A generic term describing an abnormal physiological response to an ingested food or food additive which is not a result of an immune response

Does not require “priming”

Reaction is dose-dependent: symptoms are dependent on amount and frequency of consumption

Reaction is sometimes inherited, but not always

Examples of Food Intolerances

Lactose intolerance:Deficiency of lactase

Sucrose intolerance:Deficiency of sucrase

Sulphite intolerance:Possibly deficiency of sulphite oxidase

Examples of Food Intolerances

MSG sensitivity Mechanism unknown

Sensitivity to food additivesVarious mechanisms

Sensitivity to biogenic aminesTyramineHistamine

What is Celiac Disease?

A hypersensitivity to glutena protein found in wheat, barley, rye, and certain other grains.

Chronic inflammatory disorder of small intestine.Cell-mediated allergic response.May also include dermatitis herpetiformis

a chronic skin disorder caused by an IgA-mediated hypersensitivity to gluten.

Celiac Disease

Celiac is often confused with other ailmentsirritable bowel syndrome, Crohn’s disease, etc.

GI symptoms: gas, abdominal bloating and pain, diarrhea, steatorrhea, mouth sores.Skin symptoms: dermatitis herpetiformis.Potentially asymptomatic, increasing risk for malnutrition-related symptoms and complications.

The Immune System

Designed to protect the body from invasion by foreign materials.T cell lymphocytes detect foreign proteins (antigens) in any form.T cells then trigger a series of immunological reactions, mediated by cytokines.

The Immune System

All foods contain proteins – derived from plants and animals – all of which are foreign to the human body.In order for food to be absorbed, metabolized, and utilized by the body, the immune system needs to be “educated” that the foreign material is safe.This involves a complex series of immunological reactions.

The Immune System

Oral ToleranceIn most cases this results in “education” of the T cells to not respond to that food protein when it enters via the oral route called oral tolerance.

Contrasts with the active immune responses needed to protect the gut against continual bombardment by invading pathogens and their products (toxins, etc).

The Immune System

Food allergy occurs as a result of lack of tolerance. T cells respond as if the food were a threat to the body. Antibodies are produced specifically to reject the food – called sensitization.Inflammatory mediators are released to defend the body. Mediators act on body tissues to cause the symptoms of allergy.

Inflammatory Chemicals in the Allergic Reaction

Preformed:Histamine EEnzymesChemo-attractants

Newly formedProstaglandinsLeukotrienes

Each chemical has a different effect on tissues: the allergic response is the combined effect of them all.

Symptoms of Food Allergy

http://www.cfsan.fda.gov/~dms/wh-alrg1.html

Symptoms: GI Tract

Swelling or itching of the lips, mouth and/or throat.Nausea, vomiting, cramping and/or diarrhea.Eosinophilic esophagitis/gastroenteritis may be associated with food allergic responses

Critical nutrition management role for dietitian.

Symptoms: Skin

Itching, swelling, hives, eczema and/or redness.Up to 20% of acute hives are caused by food allergy; hives lasting more than six weeks are rarely caused by food allergy.37% of children with moderate to severe atopicdermatitis also have food allergy.

Symptoms: Respiratory Tract

Congested, runny, and/or itchy nose, sneezing, raspy cough, and/or wheezing.Nasal symptoms occur in 25-80% of food allergic patients; in isolation, usually not food-related.Asthma is food-related in only 5.7% of asthmatic children.Heiner Syndrome

Rare adverse pulmonary response to cow’s milk.Can occur in a very small percentage of infants.

Symptoms: Anaphylaxis

Serious allergic reaction, and can be life-threatening.Affects multiple body systems: skin, respiratory, GI tract and cardiovascular.Anaphylactic shock: “an explosive overreaction of the body's immune system to an allergen”.Symptoms include swelling, difficulty breathing, abdominal cramps, vomiting, diarrhea, circulatory collapse, coma and death.

Symptoms: Anaphylaxis

Food is the most common cause of anaphylaxis.Other causes could be from insect stings, medicine, latex, or exercise.1-2% of Canadians live with the risk of an anaphylactic reaction.Treatment: Epinephrine (adrenaline) shot.

Symptoms: Anaphylaxis

Anaphylaxis is a growing public health issue. Fatalities are rare and usually avoidable.Measures must be in place to reduce the risk of accidental exposure and to respond appropriately in an emergency

Improved patient self management.Comprehensive school board policies.Standardized school anaphylaxis plans.Greater community support and involvement.

Diagnosis of a Food Allergy

Managed by primary care physician or board-certified allergist.Includes complete medical history and physical exam.May include food diary, completed by patient.Screening Tools

Skin Prick TestBlood Tests

Diagnosis of a Food Allergy

Elimination dietFood challengeDiagnosis involves both science and clinical judgment!Periodic re-evaluation

Dietitian’s Role

Refer a patient to their primary care physician or a board-certified allergist.Support physician/allergist during diagnosis by assisting with:

Food DiaryFood ChallengeElimination Diet

Managing Food Allergy

Avoid the allergen-containing food(s)!Develop a Food Allergy Action Plan

Inform and involve family, friends, and caretakers.Early symptom recognitionEmergency therapy: Epinephrine (adrenaline).Medical identification necklaces/bracelets.

Managing Food Allergy

InfantsFormula feeding

Hypoallergenic milk or soy based formula may be indicated.

BreastfeedingMaternal dietary restrictions may be needed.

CommunicationSharing information with others who provide and prepare food.

Managing Food Allergy

Education:Be able to identify the allergenic food and alternative names for the allergen.Avoid foods likely to contain, or be contaminated by the allergenBe aware of all terms on food labels that would indicate the possible presence of the food.Carry injectable adrenalin, and be familiar with its use in case of accidental exposure reaction. Wear a MedicAlert tag or bracelet in case of loss of consciousness in an allergic reaction.

Managing Food Allergy

EducationHigh-risk situationsCross-contactNutritional adequacy

Preventing/Delaying Allergic Disease

High-risk: Infants with family history.Breastfeeding

Verdict is still out.Some evidence of correlations between breastfeeding and reduced incidence of food allergy and asthma.CPS strongly recommends exclusive breastfeeding for the first 6 months of life for healthy, term infants.

Preventing/Delaying Allergic Disease

New AAP Clinical Report (2008)Current evidence does not support:

dietary restrictions during pregnancy or lactation.delaying introduction of allergen foods after 4-6 months of age to prevent atopic disease.

High risk infants may still benefit from nutritional intervention and delayed introduction of allergen foods.Breastfeeding is still recommended exclusively for the first 6 months.

High risk infants may be fed hydrolyzed formula versus cow’s milk formula to prevent/delay onset of food allergy.

Positive effects on eczema from delayed introduction of solids; evidence is conflicting.

Allergen Labelling in Canada

Health Canada is in the process of updating allergen labeling regulations:

To include ingredients such as flavours, flour, seasoning and margarine.Currently, not required to list these components

Food allergens that must be included in labels:peanuts, tree nuts (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachio nuts and walnuts), sesame seeds, milk, eggs, fish, crustaceans, shellfish, soy and wheat.mustard will be added to this list.Onion and garlic not included on food labels.

Allergen Labelling in Canada

Other amendments include:Gluten sources declared when food contains gluten protein or modified gluten protein from barley, oats, rye, triticale or wheat, including kamut or spelt.Sulphites declared when added directly to a food or when the total amount contained in the food is greater than 10 ppm.

Comments from the regional consultation workshops for the proposed amendments were submitted in February 2010. Final regulations will be published in the near future.

Professional & Parent Resources

Allergy & Asthma Information Association: www.aaia.caAnaphylaxis Canada: www.anaphylaxis.caCanadian Celiac Association: www.celiac.caCanadian Food Inspection Association: www.inspection.gc.caCanadian Paediatric Society: www.cps.caCanadian Society of Allergy and Clinical Immunology: www.csaci.medical.orgDealing with Food Allergies in Babies and Children. J. M. Vickerstaff Joneja, PhD, RDN. Publisher: Bull Publishing Company; 2007. ISBN: 978-1933503-05-9.Dietitians of Canada Paediatric Nutrition Network (DCPNN), Vol 8 (#2): www.dietitians.ca/networks/pediatric.asp

Professional & Parent Resources

Dietitians of Canada Practice-based Evidence in Nutrition (PEN): www.dieteticsatwork.comEat Right Ontario: www.eatrightontario.caFood Allergy & Anaphylaxis Network: www.foodallergy.orgFood Allergy News: www.foodallergynews.comMedic-Alert: www.medicalert.comSpecialty Food Shop: www.specialtyfoodshop.caWinnipeg Regional Health Authority Child Health PediatricEnteral and Parenteral Nutrition Handbook (2nd ed, Dec 2008). Author/Editor: Pat Ozechowsky (RD, CNSD). Department of Nutrition and Food Services. Contact Information: (204) 787-1447 or cginter@hsc.mb.ca

Acknowledgements

This presentation was adapted from: Understanding Food Allergy – A Primer for Dietitians (International Food Information Council), October 2007 http://www.ific.org/adacpe/foodallergycpe.cfmand Food Allergies in Canada: Dietetic and Nutritional Management (Janice Joneja), December 2007.Content revisions and updates by Jane Lac, RD Consultant Janelac.work@gmail.com