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F OOD A LLERGIES. W HAT IS A FOOD ALLERGY ? An immune reaction that occurs after eating a certain food Also known as a food hypersensitivity Autoimmune.

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Presentation on theme: "F OOD A LLERGIES. W HAT IS A FOOD ALLERGY ? An immune reaction that occurs after eating a certain food Also known as a food hypersensitivity Autoimmune."— Presentation transcript:


2 W HAT 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 C LASSIFICATION OF A LLERGIES 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 S YMPTOMS Allergy symptoms can occur seconds to hours after ingestion of the allergen Most common symptoms: swelling, sneezing, nausea, GI distress Skin Swelling of lips, tongue & face Itchy eyes Hives Rash Respiratory Tract Itching or tightness of throat Shortness of breath Dry or raspy cough Runny nose wheezing Gastrointestinal Tract Abdominal pain Nausea Vomiting diarrhea


6 F REQUENTLY 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 F OOD A LLERGY VS F OOD I NTOLERANCE 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 V ARIABILITY IN P REVALENCE 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 I NCREASED E XPOSURE 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 F OOD A LLERGIES PEANUT Milk Egg Tree Nuts Fish Shellfish Wheat Soy

12 P EANUT A LLERGY 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 P EANUT A LLERGY H YGIENE H YPOTHESIS 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 P EANUT A LLERGY P ROCESSING 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 P EANUT A LLERGY A GE OF I NTRODUCTION 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 M ILK A LLERGY 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 E GG 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 T REE 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 F ISH 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 W HEAT 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 S OY 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 C AN 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


24 C URING F OOD A LLERGIES There is currently no cure for food allergies The current recommendation is to avoid the allergen Promising treatments on the way

25 I MMUNOTHERAPY 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 A NTI -I G E T HERAPY 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 E NGINEERED R ECOMBINANT P ROTEIN 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 C HINESE H ERBAL M EDICINE 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 S UMMARY C OMMENTS 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

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