Food Allergies

1. Food Allergies

2. What is a food allergy? • An immune reaction that occurs after eating a certain food • Also known as a food hypersensitivity • Autoimmune disease • Elicits an abnormal immune response to a harmless food substance • Antibodies are released to fight the allergen • Allergen is usually a protein

3. Classification of Allergies • Allergic reactions are classified into non-IgE-mediated, IgE-mediated or mixed response • Non-IgE • Slower in onset, primarily gastrointestinal reactions • IgE mediated • Causes histamine and other chemicals to be released which trigger allergy symptoms • Rapid in onset, symptoms include anaphylaxis & urticaria

4. Symptoms • Allergy symptoms can occur seconds to hours after ingestion of the allergen • Most common symptoms: • swelling, sneezing, nausea, GI distress

5. Foods most commonly associated with allergic reactions

6. Frequently allergenic foods • Most common food allergies in young children: • Milk (casein, whey) • Eggs • Wheat (gluten) • Soy • Peanuts • Tree nuts • Shellfish • Most common food allergies in older children & adults • Fish • Shellfish • Peanuts • Tree nuts

7. Food Allergy vs Food Intolerance • Reactions to food consist of a variety of reactions to food or food additive ingestion • Usually not allergenic and caused by food intolerance • Symptom-inducing food properties • Metabolic disorders • Bacterial food contamination

8. Variability in Prevalence • Determination of the exact prevalence is difficult • Considerable variation in data collection • Self-reporting, physician assessment, skin tests, IgE levels • However, self-reports indicate that food allergy incidences are on the rise • Food allergy in infants are most common

10. Increased Exposure • Development of an allergy depends on the structure of the protein, dose of the antigen and the genetic susceptibility of the host • Non-oral exposure may be a primary risk factor • Damaged skin may allow increased exposure before tolerance has been developed through oral ingestion

11. Food Allergies • PEANUT • Milk • Egg • Tree Nuts • Fish • Shellfish • Wheat • Soy

12. Peanut Allergy • Peanut sensitization does not conclude an allergy • About 95% of sensitized individuals are not clinically allergic • Attracted the most attention because it is relatively common, typically permanent and often severe • Significantly increased globally in the past decade • 2-3x as common

13. Peanut AllergyHygiene Hypothesis • Antibiotic treatment increased ease of peanut sensitization • Studies from many countries show that early exposure of viral infection may produce a proactive effect • Children born into families with several siblings tend to have a reduced frequency of allergic sensitization

14. Peanut AllergyProcessing • Allergenic protein content depends on processing and varies by brand • Higher allergenic protein content: • More mature, larger kernels • Drying or curing at higher temperatures • Roasting • Whipped or emulsified peanut butter • Less allergenic protein content: • Small kernels • Raw peanuts • Highly processed oils had no detectable protein • It is generally advised that peanut-allergic patients avoid all peanut oils

15. Peanut AllergyAge of Introduction • Sensitization to peanuts typically occurs at an early age, therefore such patients are more likely to react at first exposure • No conclusive evidence has been found to support the theory that the allergy is developed in utero • Food allergy manifests most commonly in infancy, peaking at 1 year of age and declining by age 3 • Recommendations only in place for at-risk infants

16. Milk Allergy • 2.5% of children younger than 3 • Develops in first year of life • Most children will outgrow it • Baby Formula • Hidden Sources: deli meats, non dairy items, canned tuna fish, restaurant foods and sauces

17. Egg allergy • Affect approximately 1.5% of young children • Likely to be outgrown • Most allergic reactions associated with egg involve the skin • Hidden sources: coffee drinks with foam topping, soft or hard pretzels, cooked pasta, egg substitutes. • Vaccines

18. Tree nut allergy • 1.8 million Americans • Allergic are among the leading causes of fatal and near-fatal reactions to foods • Tree nuts = walnuts, almond, hazelnuts, coconuts, cashews, pistachios, and Brazil nuts • Tend to have a lifelong allergy • Hidden sources: Salads and salad dressing, barbecue sauce, breading for chicken, pancakes, meat-free burgers, pasta, honey, fish dishes, pie crust, mandelonas (peanuts soaked in almond flavoring), mortadella (may contain pistachios)

19. Fish and shellfish allergy • 2.3% of Americans • Salmon, tuna, and halibut • Avoid all varieties • Lifelong • Avoid seafood restaurants • Asian restaurants-fish sauce • Read ingredient lists • Avoid areas where fish is being handled or cooked • Hidden Sources: Salad dressing, Worcestershire sauce, bouillabaisse, imitation fish or shellfish, meatloaf, barbecue sauce (some are made from Worcestershire)

20. Wheat allergy • Common in children • Often confused with celiac disease • IgE-mediated response to wheat protein • May tolerate other grains • Symptoms range from mild to severe • Sources: baked goods (wheat flour), pasta, sauces thickened with flour, cereals, crackers • Substitute with amaranth, barley, corn, oat, quinoa, rice, rye, tapioca

21. Soy allergy • More common food allergies in babies and children • Major ingredient in food products • Hard to avoid • Dietitian should be consulted • Symptoms typically mild • Hidden sources: baked goods, canned tuna, cereals, crackers, infant formulas, peanut butter, sauces, and soups. • Typically can tolerate soybean oil

22. Can some individuals be allergy-prone? • Patients reacting to greater numbers of allergenic epitopes experienced more severe allergic reactions & to smaller doses • Children with egg &/or milk allergies more susceptible • Peanut-allergic patients do not usually react to other legumes such as green beans, lima beans, navy beans • 95% of peanut-allergic patients can tolerate soy

23. treatment options

24. Curing Food Allergies • There is currently no cure for food allergies • The current recommendation is to avoid the allergen • Promising treatments on the way

25. Immunotherapy • Sublingual immunotherapy (SLIT) • Oral Immunotherapy (OIT) • Contact of an antigen induces tolerance • Patient is given increasing amounts of the allergen • Conclusion: may be effective during therapy (for egg, milk and hazelnut) but there is no evidence for long-term tolerance

26. Anti-IgE Therapy • TNX-901 was given in varying doses • 450 mg dose significantly increased threshold of reactivity to peanuts from 178 mg (about ½ a peanut) to 2.8 g (about 9 peanuts) • Enough to protect against accidental ingestions • Results were inconsistent • Would require bimonthly or monthly injections for rest of patients’ life • Conclusion: May be of use in severe cases

27. Engineered Recombinant Protein • The three major allergenic proteins in peanut • Ara h 1, 2 & 3 were isolated • Necessary for binding with IgE • The recombinant proteins were significantly more effective at blocking symptoms • The modified Ara h 1, 2 & 3 proteins have been manufactured and are undergoing testing before application for FDA approval

28. Chinese Herbal Medicine • A 9-Herb preparation termed Food Allergy Herbal Formula (FAHF)-2 blocks anaphylactic symptoms • Provided full protection against symptoms in a clinical study performed on mice • The FDA has recently approved a botanical Investigational New Drug application • A phase-I clinical trial will soon be underway

29. Summary Comments • Food allergy is an autoimmune response often mistaken for food intolerance • Peanut allergy appears to be increasing • Genetic, environmental and immunological influences • Recent studies have led to improved diagnoses, management and patient education • Numerous approaches to treatment are underway