food allergies: what are they and can we prevent them?

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Food Allergies What are they and can we prevent them? Heather Mileski, RD Pediatric Gastroenterology and Nutrition, MCH

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Page 1: Food Allergies: What are they and can we prevent them?

Food Allergies

What are they and can we prevent them?

Heather Mileski, RD Pediatric Gastroenterology and Nutrition, MCH

Page 2: Food Allergies: What are they and can we prevent them?

Outline

Define allergy Differentiate between types of allergies Discuss diagnostic tools available Treatment Consider preventative measures

Page 3: Food Allergies: What are they and can we prevent them?

What is the incidence of food allergy in young children?

a) <10%

b) 10-20%

c) 20-30%

d) >30%

Garcia-Careaga, 2005

Page 4: Food Allergies: What are they and can we prevent them?

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)

Page 5: Food Allergies: What are they and can we prevent them?

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

Page 6: Food Allergies: What are they and can we prevent them?
Page 7: Food Allergies: What are they and can we prevent them?

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

Page 8: Food Allergies: What are they and can we prevent them?

Oral Allergy Syndrome

Airborne Allergen Food Allergen

Birch Apples, pears, celery, hazelnuts, kiwi, potatoes, carrots

Ragweed Melons (includes cucumbers) and bananas

Grass pollen Tomatoes

Page 9: Food Allergies: What are they and can we prevent them?

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

Page 10: Food Allergies: What are they and can we prevent them?

Mixed IgE and Non-IgE

Eosinophilic Gastroenteritis– Eosinophilic infiltration of esophagus,

stomach and small bowel mucosa Eosinophilic Esophagitis Both conditions diagnosed by biopsy

Page 11: Food Allergies: What are they and can we prevent them?

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

Page 12: Food Allergies: What are they and can we prevent them?

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

Page 13: Food Allergies: What are they and can we prevent them?

Alternative Diagnostic Tools

Name of Test Testing Technique

IgG ELISA (variety of specific tests e.g. IgG4)

Serum sample

sIgA ELISA Saliva sample

Kinesiology Muscle strength testing

Vega Testing Measures electro-magnetic pulses through the body

Carroll Testing Measures enzyme defects or deficiencies via a blood sample placed in electric current

Herman and Drost, 2004

Page 14: Food Allergies: What are they and can we prevent them?

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

Page 15: Food Allergies: What are they and can we prevent them?

Which of the following is NOT a milk protein?

a) Casein

b) Lecithin

c) Whey

Page 16: Food Allergies: What are they and can we prevent them?

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)

Page 17: Food Allergies: What are they and can we prevent them?

Prevention Guidelines – AAPOnly 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

Page 18: Food Allergies: What are they and can we prevent them?

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

Page 19: Food Allergies: What are they and can we prevent them?

Prevention Guidelines – AAPOnly 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

Page 20: Food Allergies: What are they and can we prevent them?

Is Waiting Better?

Israeli population and peanuts Swedish population and fish German GINI study

Page 21: Food Allergies: What are they and can we prevent them?

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!

Page 22: Food Allergies: What are they and can we prevent them?

ReferencesGarcia-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.