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