FOOD INTOLERANCE AND ALLERGY Flashcards
WHAT PERCENTAGE OF UK POPULATION SELF REPORT FOOD ALLERGY VS WHAT PERCENTAGE HAS BEEN REALLY DIAGNOSED?
20-30% vs 2%
FOOD INTOLERANCE MAINLY AFFECTS WHICH SYSTEM IN THE BODY?
GI
ROLE OF IMMUNE SYSTEM IN FOOD INTOLERANCE?
NONE
SYMPTOMS OF FOOD INTOLERANCE AND HOW DO THEY GO AWAY?
GAS, BLOATING, FLATULENCE, CRAMPING, DIARRHOEA..
SYMPTOMS USUALLY CORRELATED WITH THE INGESTED AMOUNT OF THE OFFENDING FOOD SO THEY GO AWAY ONCE THE FOOD LEAVES THE GI TRACT
WHAT IS THE MOST COMMON/FAMOUS CAUSE OF FOOD INTOLERANCES?
ENZYME DEFICIENCIES
APART FROM GI SYMPTOMS SIMILAR TO THOSE OF FOOD INTOLERANCE, WHICH OTHER SYMPTOMS ARE SPECIFIC FOR FOOD ALLERGIES?
- HIVES, ITCHINESS, SWELLING OF THE SKIN
- RESPIRATORY SYMPTOMS
DO ALL FOOD ALLERGIES INCLUDE ANAPHYLAXIS?
NO
WHAT DOES THE IMMUNE SYSTEM DO IN FOOD ALLERGIES?
MISTAKENLY IDENTIFIES A FOOD COMPONENT AS AN INVASIVE THREAT
2 SUB TYPES OF ADVERSE FOOD REACTIONS?
IMMUNE MEDIATED AND NON-IMMUNE MEDIATED
4 CATEGORIES OF NON-IMMUNE MEDIATED ADVERSE FOOD REACTIONS + EXPLANATIONS + EXAMPLES?
METABOLIC; ENZYME DEFICIENCIES, MALABSORPTION ( LACTOSE INTOLERANCE..)
PHARMACOLOGIC; CHEMICAL SENSITIVITY (CAFFEINE, MONOSODIUM GLUTAMATE..)
TOXIC; (FISH TOXIN, BACTERIA ETC.)
OTHER/IDIOPATHIC/UNIDENTIFIED; ADVERSE REACTIONS TO ARTIFICIAL PRESERVATIVES (E.G. SULPHITES, BENZOATES..)
WHICH OF THE 4 CATEGORIES OF NON IMMUNE MEDIATED ADVERSE REACTIONS TO FOOD IS NOT RECOGNISED BY THE BRITISH NUTRITION FOUNDATION?
TOXIC CAUSES
WHICH FOODS CONTAIN MONOSODIUM GLUTAMATE (MSG)?
SOY SAUCE, MUSHROOMS, SOME CHEESE AND TOMATOES
WHICH TRANSPORTER MOVES MONOMERS GOTTEN FROM LACTOSE BREAKDOWN (GLUCOSE AND GALACTOSE) INTO THE ENTEROCYTES FROM THE INTESTINAL LUMEN?
SGLT1
OSMOTIC DIARRHOEA IS ASSOCIATED WITH WHICH CONDITION?
LACTOSE INTOLERANCE
WHAT ARE POSSIBLE CAUSES OF LACTOSE INTOLERANCE?
LACTASE DEFICIENCY
LACTASE NON-PERSITENCE
HYPOLACTASIA
WHAT HAPPENS IN THE GI TRACT IN LACTOSE INTOLERANCE AFTER INGESTING LACTOSE?
- LACTOSE TRANSITS UNDIGESTED INTO THE LARGE INTESTINE
- GUT BACTERIA METABOLISE LACTOSE AND THE RESULTING FERMENTATION PRODUCES GAS (CO2, HYDROGEN AND METHANE)
- THE GAS PRODUCED LEADS TO FLATULENCE, BLOATING AND PAIN
- THE UNABSORBED LACTOSE AND FERMENTATION PRODUCTS (E.G. SHORT CHAIN FATTY ACIDS) RAISE THE OSMOTIC PRESSURE IN THE COLON
- THIS INCREASES FLOW OF WATER INTO THE COLON CAUSING OSMOTIC DIARRHOEA
PERCENTAGE OF WORLD POPULATION EXPERIENCING A DECREASE IN LACTATE ACTIVITY AFTER INFANCY?
65-70%
IN WHICH POPULATIONS ARE THERE THE HIGHEST LACTATE ACTIVITY LEVELS POST INFANCY?
NORTHERN EUROPEAN
PERCENTAGE OF PEOPLE IN THE UK SUFFERING FROM LACTOSE MALDIGESTION?
5%
PEOPLE OF WHICH DESCENT HAVE AMONG THE HIGHEST LACTOSE DEFICIENCY RATES?
ASIAN, AFRICAN, JEWISH, HISPANIC AND CARIBBEAN
WHICH GENE IS LACTASE ENCODED BY AND MUTATIONS IN WHICH GENE (AND THEN SUBSEQUENTLY ITS PROTEIN) HELP REGULATE THAT GENE (KEEP IT TURNED ON)
GENE ENCODING LACTASE: LCT
PROTEIN: MCM6
WHICH GENE IS LACTASE ENCODED BY AND MUTATIONS IN WHICH GENE (AND THEN SUBSEQUENTLY ITS PROTEIN) HELP REGULATE THAT GENE (KEEP IT TURNED ON)
GENE ENCODING LACTASE: LCT
PROTEIN: MCM6
OTHER NAME FOR CONGENITAL LACTASE DEFICIENCY?
ALACTASIA
PREVALENCE, CAUSE AND MANAGEMENT OF CONGENITAL ALACTASIA?
- EXTREMELY RARE
- AUTOSOMAL RECESSIVE MUTATION ON LCT GENE CAUSING COMPLETE LACK OF LACTASE FROM BIRTH
- INFANTS CANNOT BE BREASTFED OR GIVEN MILK AND THEY ARE FED WITH SOYBEAN-DERIVED FORMULAS
MOST COMMON CAUSE/TYPE OF LACTOSE INTOLERANCE?
PRIMARY
WHAT IS PRIMARY LACTOSE INT.?
PRIMARY LACTASE DEFICIENCY AKA LACTASE NON-PERSISTENCE; GENETICALLY INHERITED, ABSENCE OF LACTASE PERSISTANCE ALLELE LEADING TO AGE RELATED DECREASE IN LACTASE ACTIVITY
PRIMARY LACTOSE INTOLERANCE USUALLY PRESENTS ITSELF IN WHICH STAGE OF LIFE?
ADULTHOOD (POSSIBLE IN CHILDHOOD BUT NOT USUAL)
SECONDARY LACTASE DEFICIENCY CAUSE?
DAMAGE OF THE LINING OF THE INTESTINE WHERE LACTASE IS FORMED, CAN BE CAUSED BY VARIOUS CONDITIONS LIKE GASTROENTERITIS, COELIAC, IBS, PARASITES, MEDS…
SECONDARY LACTOSE INTOLERANCE AFFECTS CHILDREN OR ADULTS MORE?
ADULTS
CAN SECONDARY LACTOSE INTOLERANCE BE REVERSED?
YES, BY THE RECOVERY OF THE INTESTINAL WALL
ARE LACTOSE INTOLERANCE TESTS ROUTINELY PERFORMED AND WHY?
NO BECAUSE AROUND 65% OF POPULATION IS AFFECTED
WHAT IS DONE IF SOMEONE HAS SYMPTOMS OF LACTOSE INTOLERANCE?
THEY ARE FIRST ENCOURAGED TO REMOVE LACTOSE FROM DIET FOR 2 WEEKS
TESTS MAY BE PERFORMED TO DISTINGUISH BETWEEN PRIMARY AND SECONDARY
EXAMPLE OF LACTOSE INTOLERANCE TESTS AND EXPLANATION?
HYDROGEN BREATH TEST; PATIENT GIVEN 25-50g OF LIQUID GLUCOSE AFTER AN OVERNIGHT FAST, BREATH SAMPLES TAKEN EVERY 15-30 MINS FOR UP TO 3 HRS; A RISE IN BREAST HYDROGEN SUGGESTS LACTOSE WASN’T DIGESTED
LACTOSE TOLERANCE TEST; MEASURES PRODUCTION OF GLUCOSE THAT WOULD NEED TO OCCUR IF LACTOSE WAS FULLY DIGESTED AFTER AN IVERNIGHT FAST
STOOL SAMPLE FOR INFANTS AND CHILDREN BECAUSE THE PREVIOUS 2 TESTS INDUCE DIARRHEA, SEE IF STOOL HAS HIGH LEVELS OF ACIDITY AND SHORT CHAIN FATTY ACIDS
SMALL BOWEL BIOPSY IF UNDERLYING CONDITION IS SUSPECTED
HYDROGEN BREATH TEST GIVES A FALSE NEGATIVE IN WHAT PERCENTAGE OF PATIENTS?
25% (VERY SPECIFIC)
PATIENTS WITH LACTOSE INTOLERANCE USUALLY TOLERATE UP TO HOW MANY GRAMS OF LACTOSE?
12g (250mL OF MILK)
MANAGEMENT OF LACTOSE INTOLERANCE?
LOW LACTOSE AND FODMAP DIET (FERMENTABLE CARBS), PREBIOTICS, LACTASE SUPPLEMENTATION..
LACTOSE INTOLERANCE; IMPACT ON QUALITY OF LIFE:
- LOWER QOL
- ANXIETY OF INTOLERANCE GENERALIZED TO OTHER FOODS WHICH MAY LEAD TO VERY RESTRICTIVE DIETS
- CAN LEAD TO AVOIDANT/RESTRICTIVE FOOD INTAKE DISORDER
WHICH EATING DISORDER IS SOMETIMES ASSOCIATED WITH LACTOSE INTOLERANCE?
AVOIDANT/RESTRICTIVE FOOD INTAKE DISORDER
CATEGORIES OF IMMUNE MEDIATED ADVERSE FOOD REACTIONS: (I.E. THE 4 TYPES OF ALLERGIC REACTIONS/HYPERSENSITIVITIES)
IgE MEDIATED
NON IgE MEDIATED
MIXED IgE AND NON IgE
CELL MEDIATED
WHICH ANTIBODIES ARE INVOLVED IN NON IgE MEDIATED AKA TYPE II HYPERSENSITIVITY:
IgG AND IgM
WHAT ARE THE MEDIATORS IN TYPE IV HYPERSENSITIVITY?
CYTOTOXIC T CELLS AND MACROPHAGES
WHAT IS AN ALLERGEN?
AN ANTIGEN THAT PRODUCES AN ABNORMAL IMMUNE RESPONSE RESULTING IN ANTIBODY PRODUCTION
WHAT ARE THE USUAL ALLERGENS IN FOOD ON A CHEMICAL LEVEL?
PROTEINS, LIPOPROTEINS AND GLYCOPROTEINS
IMMUNOGLOBINS ARE A TYPE OF:
ANTIBODIES
HOW MANY TYPE OF IMMUNOGLOBINS ARE THERE?
5
WHAT IS THE MOST ABUNDANT AND WHAT IS THE LEAST ABUNDANT Ig?
MOST: IgG
LEAST: IgE
WHAT IS THE FRAGMENT CRYSTALLIZABLE (Fc) REGION OF ANTIBODIES?
FORMED BY 2 HEAVY CHAINS COMING TOGETHER USUALLY LINKED BY DISULFIDE BONDS
MANY IMMUNE CELLS HAVE RECEPTORS FOR IT
TYPE OF BONDS IN Fc REGION OF ANTIBODIES?
DISULFIDE BONDS
ANTIBODY BASIC STRUCTURE:
GLYCOPROTEIN CONSISTING OF 2 TYPES OF POLYPEPTIDE CHAINS (HEAVY AND LIGHT) WHICH ALSO CONTAIN CARBOHYDRATES
IgE ASSOCIATED (TYPE I) HYPER SENSITIVITIES AFFECT WHAT PERCENTAGE OF ADULTS AND WHAT PERCENTAGE OF CHILDREN?
3-8% OF CHILDREN
1-3% OF ADULTS
COMMON INDUCERS OF IgE ALLERGIES:
MILK, EGGS, WHEAT, PEANUTS, SESAME, FISH, FRUIT AND VEG
ALLERGIES TO WHICH PRODUCTS ARE OFTEN OUTGROWN AND WHICH PERSIST:
OUTGROWN: MILK, EGG, WHEAT
PERSIST: FISH, PEANUTS, TREE NUTS
HOW IS THE PREVALENCE OF TYPE I ALLERGIES CHANGING AND WHY?
IT IS INCREASING
ACCORDING TO THE HYGIENE HYPOTHESIS THE REASON IS DECREASED FAMILY SIZE AND IMPROVED FAMILY HYGIENE, EATING LESS ORGANIC FOOD AND USING MORE ANTIBIOTICS AND VACCINES
EXPLAIN ALLERGIC SENSITIZATION AND SECONDARY IMMUNE RESPONSE IN TYPE I HYPERSENSITIVITY:
REGARDLESS OF THE ALLERGEN, FIRST EXPOSURE TO THE ALLERGEN ACTIVATES A PRIMARY IgE ANTIBODY RESPONSE (SO THERE ARE IgE ANTIBODIES PRODUCED BUT THERE IS NO ALLERGIC SYMPTOMS, THE INDIVIDUAL IS JUST SENZITIZED TO AN ALLERGIC REACTION UPON SUBSEQUENT EXPOSURE
UPON SUBSEQUENT EXPOSURE, THE PRIMED IMMUNE SYSTEM REACTS WITHIN MINUTES (SECONDARY IMMUNE RESPONSE) LEADING TO A SYMPTOMATIC ALLERGIC REACTION
2 ROUTES OF ALLERGIC SENSITIZATION:
CLASS I FOOD ALLERGENS (MILK, EGG, PEANUT); ORAL ALLERGENS CAUSING SENSITIZATION THROUGH THE GI TRACT
CLASS II FOOD ALLERGENS (E.G. BIRCH POLLEN); AEROALLERGENS THAT CAUSE SENSITIZATION VIA THE RESPIRATORY TRACT
HOW MANY IgE MOLECULES CAN AN INDIVIDUAL MAST CELL BIND?
500 000
HOW MANY ALLERGEN-SPECIFIC BINDING SITES DOES EACH IgE MOLECULE CONTAIN?
2
WHAT ARE MAST CELLS?
A mast cell is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte that is a part of the immune and neuroimmune systems.
HOW ARE MAST CELLS ACTIVATED IN SECONDARY IMMUNE RESPONSE?
ALLERGENS BIND TO MULTIPLE IgE MOLECULES ON MAST CELLS AND CROSS LINK THEM WHICH ACTIVATES THE MAST CELLS AND TRIGGERS DEGRANUALTION AND THE RELEASE OF THE CONTENT OF THE GRANULES IN THE EXTRACELLULAR ENVIRONMENT
WHICH COMPONENTS ARE RELEASED FROM GRANULES OF THE MAST CELLS UPON ALLERGEN BINDING TO IgE ON THE MAST CELLS AND WHAT DO THEY DO?
HISTAMINE, SEROTONIN, BRADYKININ, LIPID MEDIATORS, CYTOKINES; ALL COLLECTIVELY CAUSE INFLAMMATION ON SYMPTOMS OF TYPE I HYPERSENSITIVITY
WHAT ARE SOME OF EXTERNAL FACTORS THAT CAN FACILITATE SENSITIZATION IN TYPE I HYPERSENSITIVITY?
ALCOHOL, STRESS, ANTI-INFLAMMATORY DRUGS, PATHOGENS..
WHEN IN LIFE DOES PRIMARY ALLERGIC SENSITIZATION OCCUR AND WHAT IS THE RESULT OF IT?
EARLY IN LIFE (CHILDHOOD)
LEADS TO T-CELL AND IgE MEMORY WHICH CAN BE BOOSTED UPON FURTHER ALLERGEN CONTACT
WHICH ANTIBOIDES ARE PRODUCED BY NON ALLERGIC INDIVIDUALS IN RESPONSE TO PRIMARY FOOD ALLERGENS?
IgG AND IgA
WHAT AFCTORS CONTRIBUTE TO THE TYPE AND SEVERITY OF ALLERGIC REACTION?
- AMOUNT OF INGESTED ALLERGEN
- THE STABILITY OF ALLERGEN AGAINST DIGESTION
- THE PERMEABILITY OF THE EPITHELIAL LAYER
EFFECTS OF HISTAMINE RELEASED FROM GRANULES OF MAST CELLS UPON SECOND EXPOSURE TO AN ALLERGEN IN TYPE I HYPERSENSITIVITIES?
- STIMULATES MUCUS SECRETION IN NASAL PASSAGES
- STIMULATES TEAR FORMATION
- WHEN IT INTERACTS WITH NERVE ENDINGS CAUSES ITCHING AND SNEEZING
- TOGETHER WITH SEROTONIN IT CAN STIMULATE VOMITING CENTERS IN THE CEREBELLUM
- RELAXATION IF INTESTINAL SMOOTH MUSCLES AND DIARRHEA
WHAT IS ANGIOEDEMA?
SWELLING AFFECTING LIPS, THROAT AND TONGUE
WHAT IS CYANOSIS?
BLUISH COLOR TO THE SKIN DUE TO LACK OF OXYGEN
WHAT IS DYSPNEA?
DIFFICULTY BREATHING
WHEN DO LATE-PHASE ALLERGIC REACTIONS DEVELOP?
4-12HRS AFTER THE EARLY/IMMEDIATE PHASE
IMMEDIATE ALLERGY REACTION IN TYPE I HYPERSENSITIVITY IS MEDIATED BY IgE AND THE LATE PHASE RESPONSE BY?
EOSINOPHILS, NEUTROPHILS AND LYMPHOCYTES
WHAT ARE MARKER ALLERGENS?
FOOD CONSTITUENTS THAT CAN BE USED TO CONFIRM SENSITIZATION TO A TYPE OF FOOD
ALLERGENIC FOODS USUALLY CONTAIN INDIVIDUAL OR MULTIPLE ALLERGENIC PROTEINS?
MULTIPLE
EGG ALLERGY PREVALENCE THROUGHOUT LIFE?
- ONE OF THE MOST PREVALENT IN CHILDHOOD (1.6-2.3% OF CHILDREN)
- AFFECTS ONLY 0.2% OF ADULT POPULATION ( OUTGROWING RATE RELATIVELY HIGH)
CROSS REACTIVITY IN ALLERGIES?
OCCURS WHEN PROTEINS IN ONE FOOD SHARE PROPERTIES WITH THOSE IN ANOTHER FOOD AND CAN CAUSE AN ALLERGIC REACTION EVEN IF THEY THEMSELVES AREN’T THE ACTUAL ALLERGEN
COELIAC DISEASE IS AN EXAMPLE OF WHAT TYPE OF ALLERGY?
NON IgE MEDIATED
