FOOD ALLERGY

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FOOD ALLERGY
Lecture Material - Food SafetyInneke Hantoro
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What is food allergy?

• Food allergy is an abnormal response to a food
  triggered by the bodys immune system.
• The symptoms of an allergic reaction are caused
  by biologically active chemicals produced by the
  immune system in its attempt to protect the body
  from a foreign invader.
• Allergic reactions to food can cause serious
  illness or even death.
• Food allergy is different with food intolerance
  although both can show similar symptoms.

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Types of food allergy

• IgE-mediated food allergy (immediate
  hypersensitivity)
• e.g. peanut allergy, cows milk allergy
• Cell-mediated food allergy (delayed
  hypersensitivity)
• involving sensitized immune cells in the small
  intestine, usually lymphocytes, that are
  sensitized to the specific substance that
  triggers the reaction ? inflammation on certain
  sites, symptoms appearing 24 hours or more after
  ingestion
• e.g. celiac disease

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How do allergic reactions work?

• An immediate allergic reaction involves two
  actions of our immune system
• Our immune system produces immunoglobullin E
  (IgE) a type of protein that works against a
  specific food antibody.
• IgE attaches basophils (white blood cells) and to
  mast cells cells found in all body tissues. The
  typical sites of allergic reactions include nose,
  throat, lungs, skin and GI tract.

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How do allergic reactions work?

• Food allergens are proteins within the food that
  enter our bloodstream after the food is digested.
• Food allergen go to target organs such as skin,
  nose, etc and cause allergic reactions.
• An allergic reaction to food can take place
  within few minutes to an hour.

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How do allergic reactions work?

• The symptoms of cell-mediated allergic reactions
  do not begin to appear until 624 hrs after
  ingestion of the offending food. These reactions
  develop slowly, reaching a peak at approx. 48 hrs
  and subsiding after 7296 hrs.
• The mechanisms of cell-mediated food allergies
  are not nearly as well understood.
• They involve an interaction between specific food
  allergens and sensitized T lymphocytes - a major
  component of the gut-associated lymphoid tissue.
  Lymphocyte stimulation initiates the release of
  cytokines and lymphokines which produces a
  localized inflammatory response.
• Antibodies are not involved in these reactions.

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Celiac disease

• Celiac disease, or gluten-sensitive enteropathy,
  is a malabsorption syndrome occurring in
  sensitive individuals upon the consumption of
  wheat, rye, barley, triticale, spelt, and kamut.
• The consumption of wheat or other offending
  grains or products made from these grains elicits
  inflammatory damage to the absorptive epithelial
  cells in the small intestine.

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Celiac disease

• The loss of absorptive function along with the
  ongoing inflammatory process results in a severe
  malabsorption syndrome characterized by diarrhea,
  bloating, weight loss, anemia, bone pain, chronic
  fatigue, weakness, muscle cramps, and, in
  children, failure to gain weight and growth
  retardation.
• The inflammatory mechanism involved in celiac
  disease is mediated by intestinal T lymphocytes.

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The allergic symptoms

• Itching in mouth as we start to eat the food.
• GI symptoms such as vomiting, diarrhea or
  abdominal pain after the food is digested in
  stomach.
• When the food allergens enter and travel through
  the bloodstream, they may cause the blood
  pressure to drop.
• As the allergens reach the skin, they can cause
  hives or eczema.
• When the allergen reach the lungs, they may cause
  asthma.

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Cross - Reactivity

• If we have a life-threatening reaction to a
  certain food, our body will show how to avoid
  similar foods that might trigger this reaction.
• For example if someone has a history of allergy
  to shrimp, he/she will also show allergic
  reactions to crab, lobster and crayfish.

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Cross contact allergen

• Cross contact allergens occur when a residue or
  other trace amount of an allergenic substance is
  unintentionally added into a food not intended to
  contain that allergenic substance and where such
  occurrences are sporadic.

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Common Food Allergies

• In adults
• Shellfish, peanuts, tree nuts (walnuts), fish,
  eggs, wheat, soy.
• In children
• Eggs, milk, peanuts, soy.
• Tree nuts and peanuts can cause deadly food
  allergy reactions called anaphylaxis!

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• Anaphylactic reaction is a severe reaction of
  rapid onset that involves most organ systems
  (multiple organ failure) and that results in
  circulatory collapse and a drop in blood
  pressure.
• The 1st symptoms usually are burning, itching,
  irritation of the lips, the inside of the mouth
  and the throat.
• Followed by nausea, vomiting, abdominal pain, and
  diarrhea.

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Food Allergen

• The allergenic moiety of the food is usually a
  protein.
• Allergenic proteins are usually not denatured
  under food processing conditions and relatively
  resistant to digestion.
• Other foods can produce allergen as well, but not
  as often, e.g. strawberries.
• The foods to which adults or children usually
  react are those foods they eat often, e.g.
• Soy and rice allergy in Japan
• Codfish allergy in Scandinavia
• Peanuts allergy in US

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Types of Food Allergens

• Milk proteins caseins, whey proteins
  (beta-lactoglobulin), serum proteins (albumin).
• Egg proteins ovalbumin, conalbumin
  (ovotransferrin) and ovomucoid (heat stable).
• Grain proteins gliadins, glutenins, albumins and
  globulins.
• Peanuts ? the most frequently cited causes of
  life threatening anaphylactic reactions!
• Soy bean
• Seafood
• etc

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Food Allergy Tests

• Skin tests
• Identifying the type of IgE that is fixed to the
  skin mast cell. For example scratch test.
• Blood tests ? analyze blood or blood serum
• RAST (radioallergosorbent test) or ELIZA (
  enzyme-linked immunosorbent assay).
• These tests measure the presence of
• food-specific IgE in blood and
• the total IgE level in blood.

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Food Intolerance

• Food intolerance is more common than food
  allergy, but it doesnt relate to the immune
  system.
• Food intolerance is caused by the lack of our
  bodys ability to digest certain substances.
• Some people may have a food intolerance that has
  a psychological trigger.

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Types of Food Intolerance

• Food poisoning foods contaminated with microbes,
  such as bacteria and bacterial products (e.g.
  toxins).
• Histamine toxicity
• A reaction like an allergic reaction when people
  consume histamine containing foods, such as in
  cheese, some wines, tuna and mackerel.

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Types of Food Intolerance

• Lactose intolerance
• It caused by lactase deficiency.
• Lactase is an enzyme that is in the lining of the
  gut.
• Lactase breaks down lactose, a sugar found in
  milk and most milk products.
• Lactose is used by bacteria to form gas which
  causes bloating, abdominal pain and diarrhea.
• At least one out of ten people suffer lactose
  intolerance.

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Types of Food Intolerance

• Food additives, such as
• MSG, when it is taken in large amounts can cause
  some of the following signs flushing, sensation
  of warmth, headache, chest discomfort and feeling
  of detachment.
• Sulfites, in high concentrations can pose problem
  for people with severe asthma.

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How to treat food allergy?

• Avoiding to eat foods which can trigger allergic
  reaction.
• Exercised- induced food allergy
• The allergic symptoms may appear as exercise
  increases and body temperature rises. Therefore,
  it is required to avoid eating for a couple of
  hours before exercising.
• Taking medicine such as antihistamines to relieve
  GI symptoms, hives, sneezing and runny nose or
  taking bronchodilators to relieve asthma symptoms.

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Consumer Protections Labeling

• Food manufacturers are generally responsible
  about posting alerts concerning allergen
  contamination and recalling their products.
• Labeling of foods containing allergens have to be
  clear and consistent.
• The application of GMP in food manufacturing to
  avoid cross-contamination of food products by
  foreign allergens.
• The awareness of the consumers in checking the
  labels.

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Labeling

• The general labeling recommendations are
• all allergen information should be grouped
  together to be easily identified and not hidden
  amongst other labeling information
• product description and representation should
  provide an accurate expectation of the product
  and should not be misleading

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Labeling

• The print size should be big enough to be easily
  read, preferably at a minimum 1.5mm with sans
  serif font, and the font colour should contrast
  distinctly from the background. The use of lower
  or upper case will depend on the overall
  presentation of labeling information.
• (FSZAN)

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Labeling

• A consistent approach in the presentation of
  allergen information will help allergic consumers
  more quickly and easily identify foods of
  concern, helping to minimize accidental
  consumption of unsuitable foods.
• The recommended format consists of
• an ingredient list declaring in bold allergenic
  substances and their derivatives and
• an allergen summary statement and
• a precautionary statement.

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Labeling
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References

• Food Allergy An Overview. 2004. U.S. Department
  of Health and Human Services. Retrieved from
  www.niaid.nih.gov.
• Joneja, J. V.1998. Dietary Management of Food
  Allergens and Intolerances A Comprehensive Guide
  2nd Edition.J. A. Hall Publications LTD.
  Vancouver.