Food Allergies
A food allergy is defined as an adverse health effect arising from a specific immune response that occurs reproducibly on exposure to a given food.
The Big 8 account for 90 % of allergic reactions:
- Milk
- Egg
- Peanut
- Tree Nut
- Shellfish
- Fish
- Soy Wheat
Onset:
- Symptoms occur within minutes up to 2 hours.
- Reaction involves the immune system.
- Usually involves skin, gastrointestinal tract and respiratory tract. Symptoms may include hives, itching, diarrhea, coughing, runny nose and in extreme circumstances anaphylaxis.
Incidence:
- 3-4 % of teens and adults have food allergies
Self-Diagnosis
- Up to 34% of people think they have a food allergy
- 50-90% of people are wrong.
Proper Testing
- Testing with licensed medical provider. This may include a skin prick/puncture test, a specific IgE test or a supervised Oral Food Challenge.
Non Standard and/or unproven testing not recommended for diagnosis
- Basophil histamine release/activation
- Facial thermography
- Gastric juice analysis
- Endoscopic allergen provocation
- Hair analysis
- Applied kinesiology
- Provocation neutralization
- Allergen specific Ig G4
- Cytotoxicity assays
- Electrodermal test (Vega)
- Mediator release assay (LEAP diet)
What IS NOT a food allergy?
Food Sensitivity:
- Occurs when body creates an antibody to a specific substance.
- Does not necessarily manifest in a food allergy.
- May or may not result in unpleasant reactions.
- Is not life threatening
Food Intolerance:
- Occurs when the body lacks an enzyme to digest a certain food.
- Is not life threatening
- Does not involve an immune response
Celiac Disease
- Affects 1% of the US population.
- Is an autoimmune disorder and disease of malabsorption. Gluten, a component of wheat, barley and rye, cause an inflammatory response and damages the mucosal lining of the gastrointestinal tract.
- Proper diagnosis includes blood test followed by a biopsy of the intestinal tract.
- Celiac disease is not the same as wheat allergy. Celiac disease is triggered by gluten, a component in several grains. Wheat allergy involves one or more proteins in the wheat grain only.
Non Celiac Gluten Sensitivity (NCGS)
- Currently no diagnostic tests available.
- Must first, test negative for celiac disease and wheat allergy to determine sensitivity.
- Involves a trial of gluten free diet. If symptoms resolve with elimination of gluten, proceed with gluten challenge to confirm.
- It is not definitive if gluten is the sole responsible agent.
- Needs further study.
Source: Academy of Nutrition and Dietetics, The Journal for Nurse Practitioners Oct. 2014