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Food Intolerances

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Food Intolerances. Biochemical and Physiological Reactions. Characteristics of Food Intolerances. Non-immunologically-mediated reactions May be a result of: Enzyme deficiencies Malabsorption Many mechanisms imperfectly understood. Characteristics of Food Intolerances. Dose-related: - PowerPoint PPT Presentation
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Page 1: Food Intolerances

Food IntolerancesFood Intolerances

Biochemical and Biochemical and Physiological ReactionsPhysiological Reactions

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Characteristics of Food IntolerancesCharacteristics of Food Intolerances

Non-immunologically-mediated reactionsNon-immunologically-mediated reactions May be a result of:May be a result of:

Enzyme deficienciesEnzyme deficiencies MalabsorptionMalabsorption Many mechanisms imperfectly Many mechanisms imperfectly

understoodunderstood

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Characteristics of Food IntolerancesCharacteristics of Food Intolerances

Dose-related:Dose-related: Individual limit of toleranceIndividual limit of tolerance As quantity exceeds this, symptoms As quantity exceeds this, symptoms

increase in incidence and severityincrease in incidence and severity

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Carbohydrate IntoleranceCarbohydrate Intolerance

Patients complain of abdominal fullness, bloating, Patients complain of abdominal fullness, bloating, and cramping within 5-30 minutes after ingesting and cramping within 5-30 minutes after ingesting carbohydratecarbohydrate

Watery diarrhoea occurs from 5 minutes to 5 Watery diarrhoea occurs from 5 minutes to 5 hours after ingestionhours after ingestion

Occasionally vomitingOccasionally vomiting Excoriation of perianal skin and buttocks due to Excoriation of perianal skin and buttocks due to

acid (pH less than 6) stool in babies and childrenacid (pH less than 6) stool in babies and children Adults do not usually experience such a low stool Adults do not usually experience such a low stool

pHpH

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Carbohydrate Intolerance:Carbohydrate Intolerance: Causes of Intestinal Symptoms Causes of Intestinal Symptoms

Non-hydrolysed carbohydrates (polysaccharides, Non-hydrolysed carbohydrates (polysaccharides, oligosaccharides and disaccharides) pass into the large oligosaccharides and disaccharides) pass into the large intestine causing:intestine causing: Osmotic imbalance: induces a net fluid secretion into the Osmotic imbalance: induces a net fluid secretion into the

gut lumen resulting in loose stoolgut lumen resulting in loose stool Increased bacterial fermentation resulting in production of:Increased bacterial fermentation resulting in production of:

Organic acids (acetic, lactic, butyric, propionic) Organic acids (acetic, lactic, butyric, propionic) increase osmotic imbalanceincrease osmotic imbalance

Gases such as carbon dioxide and hydrogen Gases such as carbon dioxide and hydrogen cause bloating and flatulencecause bloating and flatulence

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Carbohydrate Intolerance:Carbohydrate Intolerance: Causes of Intestinal Symptoms Causes of Intestinal Symptoms

Increased bulk results in increased stool Increased bulk results in increased stool volumevolume

Increased fluid and acid environment stimulate Increased fluid and acid environment stimulate intestinal motility and accelerate intestinal intestinal motility and accelerate intestinal transit time. transit time.

Increased speed of intestinal transit results in:Increased speed of intestinal transit results in: loose stool since fluid is not absorbed from loose stool since fluid is not absorbed from

foodfood secondary malabsorption of fatsecondary malabsorption of fat

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Disaccharidase DeficiencyDisaccharidase Deficiency Carbohydrates are broken down by digestive enzymes Carbohydrates are broken down by digestive enzymes

to oligosaccharides and finally disaccharidesto oligosaccharides and finally disaccharides Disaccharides are broken down by disaccharidases Disaccharides are broken down by disaccharidases

produced by brush border cells in the small intestine produced by brush border cells in the small intestine to monosaccharidesto monosaccharides

Monosaccharides are absorbed by active transport or Monosaccharides are absorbed by active transport or facilitated diffusionfacilitated diffusion

Deficiency in disaccharidases results in Deficiency in disaccharidases results in malabsorption of disaccharide which passes into large malabsorption of disaccharide which passes into large bowelbowel

Symptoms result from:Symptoms result from: Changes in osmotic pressureChanges in osmotic pressure Fermentation by micro-organismsFermentation by micro-organisms

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Lactose IntoleranceLactose Intolerance Due to lactase deficiency Due to lactase deficiency Lactase splits lactose into monosaccharides:Lactase splits lactose into monosaccharides:

GlucoseGlucose GalactoseGalactose

Monosaccharides absorbed by active transportMonosaccharides absorbed by active transport Undigested lactose moves into colon:Undigested lactose moves into colon:

Change in osmotic pressure Change in osmotic pressure Provides substrate for microbial fermentationProvides substrate for microbial fermentation

Results in Results in Excess fluidExcess fluid Organic acidsOrganic acids Gases including hydrogenGases including hydrogen

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Types of Lactose IntoleranceTypes of Lactose Intolerance

Three types of lactose intolerance:Three types of lactose intolerance:1.1. Congenital alactasiaCongenital alactasia

Present from birthPresent from birth2.2. Idiopathic lactase deficiencyIdiopathic lactase deficiency

Natural attrition after infancyNatural attrition after infancy Affects about 80% of the world’s adult populationAffects about 80% of the world’s adult population

3.3. Secondary lactase deficiencySecondary lactase deficiency Results from damage to the lactase-producing Results from damage to the lactase-producing

brush border cells, often as a result of intestinal brush border cells, often as a result of intestinal infectioninfection

Usually temporary condition that resolves once the Usually temporary condition that resolves once the infection of intestinal damage resolvesinfection of intestinal damage resolves

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Tests for Lactose IntoleranceTests for Lactose Intolerance

Tests require ingestion of lactose: usually 50 gm Tests require ingestion of lactose: usually 50 gm lactose powderlactose powder

Hydrogen breath test: positive >20 ppmHydrogen breath test: positive >20 ppm Blood glucose or galactose levels: increase indicates Blood glucose or galactose levels: increase indicates

negative testnegative test Reducing substance in stool: presence indicates Reducing substance in stool: presence indicates

positive test (Fehlings solution changes colour from positive test (Fehlings solution changes colour from blue to red)blue to red)

Fecal pH: low pH indicates lactose fermentation and Fecal pH: low pH indicates lactose fermentation and hence positive testhence positive test

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Management of Lactose Management of Lactose IntoleranceIntolerance

Only the milk sugar, lactose, needs to be avoidedOnly the milk sugar, lactose, needs to be avoided Milk proteins are toleratedMilk proteins are tolerated Lactose occurs in the whey (liquid) fraction of milkLactose occurs in the whey (liquid) fraction of milk Milk products free from lactose and free from Milk products free from lactose and free from

whey are safewhey are safe These foods include:These foods include:

Milk treated with lactase (LactaidMilk treated with lactase (Lactaid; Lacteeze; Lacteeze)) Hard cheeses (whey is removed; casein remains and is Hard cheeses (whey is removed; casein remains and is

fermented to form cheese)fermented to form cheese) Many people tolerate yogurt, where lactose is broken Many people tolerate yogurt, where lactose is broken

down by bacterial enzymesdown by bacterial enzymes

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Sucrase-Isomaltase DeficiencySucrase-Isomaltase Deficiency

Primary deficiency is rare: it is inherited as Primary deficiency is rare: it is inherited as an autosomal recessive genean autosomal recessive gene

Greenland and Canadian Inuit have an Greenland and Canadian Inuit have an unusual incidence of 10% of the populationunusual incidence of 10% of the population

Appears when sucrose enters the child’s Appears when sucrose enters the child’s diet, usually when fruit juice is introduceddiet, usually when fruit juice is introduced

Severity of symptoms depends on the Severity of symptoms depends on the quantity of sucrose in the dietquantity of sucrose in the diet

Management: Avoidance of all sources of Management: Avoidance of all sources of sucrosesucrose

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Fructose Fructose IntoleranceIntolerance

Fructose intolerance is an inability to absorb free Fructose intolerance is an inability to absorb free fructose fructose

Intestinal fructose absorption depends on a low-Intestinal fructose absorption depends on a low-affinity transporter molecule, GLUT2 that will carry affinity transporter molecule, GLUT2 that will carry the monosaccharides glucose, fructose and galactose the monosaccharides glucose, fructose and galactose across the small intestine epithelium. across the small intestine epithelium.

This carrier mechanism is facilitated by glucose, This carrier mechanism is facilitated by glucose, which permits lower concentrations of glucose to be which permits lower concentrations of glucose to be taken up by the cell by an active processtaken up by the cell by an active process

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Fructose IntoleranceFructose Intolerance

Glucose is preferentially absorbedGlucose is preferentially absorbed An excess of fructose will result in inefficient An excess of fructose will result in inefficient

absorption of the fructoseabsorption of the fructose The unabsorbed fructose moves into the large bowel The unabsorbed fructose moves into the large bowel

where it causes:where it causes: An increase in osmotic pressureAn increase in osmotic pressure Net influx or reduced outflow of waterNet influx or reduced outflow of water Acts as a substrate for microbial fermentation with Acts as a substrate for microbial fermentation with

production of gas (especially hydrogen) and organic acidsproduction of gas (especially hydrogen) and organic acids Resulting in loose stool or frank diarrhoeaResulting in loose stool or frank diarrhoea

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Fructose Intolerance:Fructose Intolerance:The Problem FoodsThe Problem Foods

It is usually only necessary to avoid the foods It is usually only necessary to avoid the foods that contain considerably more fructose than that contain considerably more fructose than glucose These foods include:glucose These foods include: AppleApple PearPear CherryCherry BlackcurrantBlackcurrant WatermelonWatermelon HoneyHoney High fructose corn syrupHigh fructose corn syrup Agave syrupAgave syrup

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Pharmacologic Agents in FoodsPharmacologic Agents in Foods

Vasoactive amines:Vasoactive amines: HistamineHistamine TyramineTyramine PhenylethylaminePhenylethylamine OctopamineOctopamine SerotoninSerotonin

MethylxanthinesMethylxanthines CaffeineCaffeine TheobromineTheobromine TheophyllineTheophylline

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Pharmacologic Agents in FoodsPharmacologic Agents in Foods

Pharmacologic properties may be expressed in Pharmacologic properties may be expressed in two ways:two ways: Chemical reacts directly with body tissue in Chemical reacts directly with body tissue in

a dose-dependent fashiona dose-dependent fashion Chemical reacts with a mediator system that Chemical reacts with a mediator system that

acts on the body tissueacts on the body tissue

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HistamineHistamine

Histamine-mediated reactions may be Histamine-mediated reactions may be clinically indistinguishable from food clinically indistinguishable from food allergyallergy

Histamine sensitivity is becoming Histamine sensitivity is becoming recognized as a disease entity quite distinct recognized as a disease entity quite distinct from allergyfrom allergy

““Idiopathic” urticaria and angioedema is an Idiopathic” urticaria and angioedema is an example of histamine sensitivityexample of histamine sensitivity

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Symptoms of Histamine ExcessSymptoms of Histamine Excess

Vasodilatation Vasodilatation FlushingFlushing ReddeningReddening

Hypotension:Hypotension: Tachycardia (Increased heart rate)Tachycardia (Increased heart rate)

Increased vascular permeabilityIncreased vascular permeability urticaria (hives)urticaria (hives) angioedema (swelling)angioedema (swelling) rhinitis (stuffy nose)rhinitis (stuffy nose) rhinorrhea (runny nose)rhinorrhea (runny nose) otitis media (earache)otitis media (earache)

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Symptoms of Histamine ExcessSymptoms of Histamine Excesscontinuedcontinued

Pruritus (itching)Pruritus (itching) Increase in gastric secretionsIncrease in gastric secretions

HeartburnHeartburn RefluxReflux

Headache; usually not migraineHeadache; usually not migraine Symptoms of anxiety; panic attackSymptoms of anxiety; panic attack Rarely momentary loss of consciousnessRarely momentary loss of consciousness Fatigue; listlessnessFatigue; listlessness ConfusionConfusion

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Other Effects of Histamine ExcessOther Effects of Histamine Excess

Increase in incidence and severity of Increase in incidence and severity of anaphylactic reactionsanaphylactic reactions

Increase in incidence and severity of Increase in incidence and severity of eczemaeczema

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Mechanism of Histamine SensitivityMechanism of Histamine Sensitivity

Excess histamine is controlled by two Excess histamine is controlled by two enzyme systems: enzyme systems: Histamine N-methyltransferase (HMT)Histamine N-methyltransferase (HMT) Diamine oxidase (DAO)Diamine oxidase (DAO)

Normally DAO rapidly degrades histamine Normally DAO rapidly degrades histamine to its inactive metabolites (imidazole to its inactive metabolites (imidazole compounds) which are excreted in urinecompounds) which are excreted in urine

HMT prevents prolonged binding of HMT prevents prolonged binding of histamine to its receptorshistamine to its receptors

Prevents histamine-induced symptomsPrevents histamine-induced symptoms

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Mechanism of Histamine SensitivityMechanism of Histamine Sensitivity

Symptoms develop when:Symptoms develop when: Excessive amounts of histamine exceed Excessive amounts of histamine exceed

the enzymes’ capacity to break it downthe enzymes’ capacity to break it down There is a lowered enzyme capacity for There is a lowered enzyme capacity for

histamine breakdownhistamine breakdown Drugs inhibit enzyme action (e.g. Drugs inhibit enzyme action (e.g.

isoniazid)isoniazid)

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Sites of Diamine Oxidase ProductionSites of Diamine Oxidase Production

DAO produced in various tissues, especially:DAO produced in various tissues, especially: JejunumJejunum IleumIleum KidneyKidney ThymusThymus PlacentaPlacenta

Many women experience relief of symptoms Many women experience relief of symptoms of allergy and histamine sensitivity during of allergy and histamine sensitivity during pregnancypregnancy

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Sources of Histamine in FoodsSources of Histamine in Foods

Histidine can be decarboxylated to histamine Histidine can be decarboxylated to histamine by intestinal bacteriaby intestinal bacteria

May develop in fish that have been May develop in fish that have been improperly processed and refrigerated, improperly processed and refrigerated, especially:especially:

TunaTuna MackerelMackerel BonitoBonito BluefishBluefish Mahi mahi]Mahi mahi]

In shellfish, where intestine is not removedIn shellfish, where intestine is not removed

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Sources of Histamine in FoodsSources of Histamine in Foods

Histamine is produced by microbial action in Histamine is produced by microbial action in manufacture of foods such as:manufacture of foods such as: CheeseCheese Fermented meats and sausagesFermented meats and sausages WineWine BeersBeers VinegarVinegar Yeast extractYeast extract SauerkrautSauerkraut

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Sources of Histamine in FoodsSources of Histamine in Foods

Some foods contain high levels of histamine Some foods contain high levels of histamine naturally, especially:naturally, especially:

SpinachSpinach AubergineAubergine

Plant foods may produce histamine during the Plant foods may produce histamine during the ripening process, for exampleripening process, for example

TomatoTomato CherriesCherries

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Sources of Histamine in FoodsSources of Histamine in Foods

Some foods may release histamine by a Some foods may release histamine by a non-immunologically mediated mechanism non-immunologically mediated mechanism which is presently unknown. Such foods which is presently unknown. Such foods include:include:

Egg white Egg white StrawberryStrawberry Alcohol (ethanol)Alcohol (ethanol) Citrus fruitsCitrus fruits

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Other Sources of HistamineOther Sources of Histamine

Compounds that release histamineCompounds that release histamine:: Food additives, especially:Food additives, especially:

BenzoatesBenzoates Tartrazine and other azo dyesTartrazine and other azo dyes SulphitesSulphites

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Other Extrinsic Sources of HistamineOther Extrinsic Sources of Histamine

Microbial flora of the large bowel includes Microbial flora of the large bowel includes species that synthesise histidine species that synthesise histidine decarboxylasedecarboxylase

Microbial enzymes act on food residue Microbial enzymes act on food residue forming histamineforming histamine

If diamine oxidase (DAO) in the gut is If diamine oxidase (DAO) in the gut is deficient, histamine is absorbed into deficient, histamine is absorbed into circulationcirculation

When there is normal DAO activity only When there is normal DAO activity only 1% of extrinsic histamine enters circulation1% of extrinsic histamine enters circulation

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Tyramine sensitivityTyramine sensitivity Symptoms:Symptoms:

UrticariaUrticaria Migraine headachesMigraine headaches Sharp rise in blood pressureSharp rise in blood pressure

Due toDue to:: Vasoconstriction induced by dietary tyramineVasoconstriction induced by dietary tyramine

Directly because of lack of tyramine breakdown in Directly because of lack of tyramine breakdown in the intestine, liver, or arterial walls the intestine, liver, or arterial walls

Indirectly via secretion of epinephrine or Indirectly via secretion of epinephrine or norepinephrine, which is normally kept at norepinephrine, which is normally kept at unreactive levels by MAO-Aunreactive levels by MAO-A

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Tyramine Sensitivity:Tyramine Sensitivity: Characteristics Characteristics

Mechanism of actionMechanism of action:: Low levels of monoamine oxidase Low levels of monoamine oxidase

(MAO-A and MOA-B) enzymes(MAO-A and MOA-B) enzymes Causes of low MAOsCauses of low MAOs::

Genetic predispositionGenetic predisposition Monoamine oxidase inhibiting drugs (e.g. Monoamine oxidase inhibiting drugs (e.g.

antidepressants such as Parnate; Nardil)antidepressants such as Parnate; Nardil)

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Tyramine in FoodsTyramine in Foods

Formed by microbial action in food Formed by microbial action in food preparation, especiallypreparation, especially:: CheeseCheese WineWine YeastYeast VinegarVinegar

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Tyramine in FoodsTyramine in Foods

Small amounts occur naturally in Small amounts occur naturally in some foodssome foods:: Chicken liverChicken liver AvocadoAvocado BananaBanana PlumPlum TomatoTomato AubergineAubergine

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Sensitivity to Food AdditivesSensitivity to Food Additives

Characteristics common to persons sensitive to Characteristics common to persons sensitive to food additives:food additives:

History of asthma and rhinitis - sometimes with History of asthma and rhinitis - sometimes with urticaria and angioedemaurticaria and angioedema

Aspirin sensitiveAspirin sensitive

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Additives Most Frequently Causing Additives Most Frequently Causing IntolerancesIntolerances

Tartrazine (and other artificial colors)Tartrazine (and other artificial colors)

SulphitesSulphites

Preservatives:Preservatives:

BenzoatesBenzoates

SorbatesSorbates

Monosodium glutamate (MSG)Monosodium glutamate (MSG)

Nitrates and nitritesNitrates and nitrites

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Symptoms of Tartrazine SensitivitySymptoms of Tartrazine Sensitivity

AsthmaAsthma UrticariaUrticaria AngioedemaAngioedema NauseaNausea Migraine headachesMigraine headaches Some evidence of neurological Some evidence of neurological

and behavioural reactionsand behavioural reactions

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Postulated mechanisms to explainPostulated mechanisms to explain Tartrazine Sensitivity Tartrazine Sensitivity

Inhibition of the cyclo-oxygenase Inhibition of the cyclo-oxygenase pathway of arachidonic acid pathway of arachidonic acid breakdown. breakdown.

Histamine release from mast cellsHistamine release from mast cells

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Allergic Response:Allergic Response:Secondary Mediator ReleaseSecondary Mediator Release

Arachidonic acidArachidonic acid

Lipoxygenase

LEUKOTRIENES

LTA4

LTB4LTC4

LTD4

LTE4

Cyclo-oxygenase

PROSTAGLANDINS (PG2)

PROSTACYCLIN (PGI2)

THROMBOXANE (TX)

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Foods Frequently Containing TartrazineFoods Frequently Containing Tartrazine

Soft drinksSoft drinks Liqueurs and cordialsLiqueurs and cordials Sweets and confectionerySweets and confectionery Ready-to-eat cerealsReady-to-eat cereals Jams and jelliesJams and jellies Ice cream, sherbet, milk shakesIce cream, sherbet, milk shakes Commercial gravies and soup mixesCommercial gravies and soup mixes Flavor packetsFlavor packets Pickles, relish, salad dressingsPickles, relish, salad dressings Prepared baked goodsPrepared baked goods Smoked fish and fish productsSmoked fish and fish products

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Foods Frequently Containing Foods Frequently Containing TartrazineTartrazine

Snack foodsSnack foods Meal replacementsMeal replacements Any food containing “artificial color” may contain Any food containing “artificial color” may contain

tartrazine unless it is labeled “tartrazine free”tartrazine unless it is labeled “tartrazine free”

Non-food items:Non-food items: Medications (prescription and OTC)Medications (prescription and OTC) Vitamin and mineral supplementsVitamin and mineral supplements Toiletries and cosmeticsToiletries and cosmetics

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Sulphite SensitivitySulphite Sensitivity

Most common in asthmaticsMost common in asthmatics Steroid-dependent asthmatics are most at riskSteroid-dependent asthmatics are most at risk Adverse reactions to sulphites is estimated to be as high as Adverse reactions to sulphites is estimated to be as high as

1% of the U.S. population1% of the U.S. population Sulphite sensitivity in non-asthmatics is considered to be Sulphite sensitivity in non-asthmatics is considered to be

quite rarequite rare Symptoms occur in most organ systems:Symptoms occur in most organ systems:

LungsLungs Gastrointestinal tractGastrointestinal tract Skin and mucous membranesSkin and mucous membranes Life-threatening anaphylactic reactions in asthmatics Life-threatening anaphylactic reactions in asthmatics

have been recorded, but occur very rarely.have been recorded, but occur very rarely.

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Symptoms Reported in Sulphite SensitivitySymptoms Reported in Sulphite Sensitivity

Severe respiratory reactions: bronchospasm; Severe respiratory reactions: bronchospasm; wheezing; “chest tightness”wheezing; “chest tightness”

Asthma in asthmaticsAsthma in asthmatics

Flushing; “change in body temperature”Flushing; “change in body temperature”

Hypotension (drop in blood pressure)Hypotension (drop in blood pressure)

Gastrointestinal symptoms (abdominal pain, Gastrointestinal symptoms (abdominal pain, diarrhea, nausea, vomiting)diarrhea, nausea, vomiting)

Swallowing difficultySwallowing difficulty

Dizziness; loss of consciousnessDizziness; loss of consciousness

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Symptoms Reported in Sulphite SensitivitySymptoms Reported in Sulphite Sensitivity

Urticaria (hives)Urticaria (hives)

Angioedema (swelling, especially of the Angioedema (swelling, especially of the mouth and face)mouth and face)

Contact dermatitisContact dermatitis

Anaphylaxis (in asthmatics)Anaphylaxis (in asthmatics)

Anaphylactoid reaction (non-asthmatics)Anaphylactoid reaction (non-asthmatics)

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Postulated Mechanisms to Explain Sulphite Postulated Mechanisms to Explain Sulphite SensitivitySensitivity

1.1. Sulphur dioxide is formed from sulphuric acid when the Sulphur dioxide is formed from sulphuric acid when the sulphite dissolvessulphite dissolves

Acts as a direct irritant on hypersensitive airwaysActs as a direct irritant on hypersensitive airways

2.2. Sulphite acts as a hapten, combines with a body protein Sulphite acts as a hapten, combines with a body protein to form a neoantigen that elicits antigen-specific IgEto form a neoantigen that elicits antigen-specific IgE

Results in Type I hypersensitivity reactionResults in Type I hypersensitivity reaction

3. Enzyme deficiency3. Enzyme deficiency::

Deficiency of sulphite oxidase system which Deficiency of sulphite oxidase system which converts sulphite to the inert sulfateconverts sulphite to the inert sulfate

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Forms of Sulphites Permitted in Foods in Forms of Sulphites Permitted in Foods in the UKthe UK

E220 E220 Sulphur dioxideSulphur dioxide E221 E221 Sodium sulphiteSodium sulphite E222 E222 Sodium hydrogen sulphiteSodium hydrogen sulphite E223 E223 Sodium metabisulphiteSodium metabisulphite E224 E224 Potassium metabisulphitePotassium metabisulphite E226 E226 Calcium sulphiteCalcium sulphite E227 E227 Calcium hydrogen sulphiteCalcium hydrogen sulphite E228 E228 Potassium hydrogen sulphitePotassium hydrogen sulphite E150b E150b Caustic sulphite caramelCaustic sulphite caramel E150d E150d Sulphite ammonia caramelSulphite ammonia caramel

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Sulphites Permitted in FoodsSulphites Permitted in Foods EU food labelling rules require pre-packed EU food labelling rules require pre-packed

food sold in the UK to show clearly on the food sold in the UK to show clearly on the label if it contains sulphur dioxide or label if it contains sulphur dioxide or sulphites at levels above 10mg per kg or sulphites at levels above 10mg per kg or 10mg per litre (or if one of its ingredients 10mg per litre (or if one of its ingredients contains it)contains it)

Non-pre-packaged foods (e.g. 'loose' foods Non-pre-packaged foods (e.g. 'loose' foods or foods prepared on the premises, or foods prepared on the premises, including take-aways and restaurant food) including take-aways and restaurant food) are not covered by this labelling are not covered by this labelling requirement requirement

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Sulphite SensitivitySulphite Sensitivity Exposure to sulphiting agents poses very Exposure to sulphiting agents poses very

little risk for individuals who are not little risk for individuals who are not sensitive to sulphitessensitive to sulphites

There is no evidence that avoiding all There is no evidence that avoiding all sources of dietary sulphites improves sources of dietary sulphites improves asthmaasthma

Sulphates do not cause the same adverse Sulphates do not cause the same adverse reactions as sulphites. They are inert in the reactions as sulphites. They are inert in the body and need not be avoided by people body and need not be avoided by people who are sensitive to sulphiteswho are sensitive to sulphites

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Sulphite SensitivitySulphite Sensitivity

Sulphites in foods are not denatured by Sulphites in foods are not denatured by cooking cooking

Sulphites avidly bind to several Sulphites avidly bind to several substances in foods, such as protein, substances in foods, such as protein, starch, and sugars. starch, and sugars.

Sulphites cannot be removed by washingSulphites cannot be removed by washing

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Benzoate Intolerance Benzoate Intolerance SymptomsSymptoms

Reported to induce:Reported to induce: UrticariaUrticaria AngioedemaAngioedema AsthmaAsthma RhinitisRhinitis Purpura (allergic vasculitis)Purpura (allergic vasculitis)

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Benzoates and Parabens:Benzoates and Parabens:Use in FoodsUse in Foods

One of the most commonly used food additives One of the most commonly used food additives worldwideworldwide

Benzoic acid and sodium benzoate (benzoates) are Benzoic acid and sodium benzoate (benzoates) are used as antibacterial and antimycotic agents in used as antibacterial and antimycotic agents in foods and beveragesfoods and beverages

Benzoates are most effective as preserving agents Benzoates are most effective as preserving agents at an acidic pHat an acidic pH

Benzoyl peroxide is used as a bleaching agent, Benzoyl peroxide is used as a bleaching agent, especially in white flour, white bread, and some especially in white flour, white bread, and some white Italian cheeseswhite Italian cheeses

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Benzoates Benzoates Naturally occurringNaturally occurring

Benzoates occur widely in nature as simple salts Benzoates occur widely in nature as simple salts (sodium, potassium), esters, and amides(sodium, potassium), esters, and amides

Natural benzoates are present at the highest levels Natural benzoates are present at the highest levels in:in:

Cinnamon, Clove, Thyme, NutmegCinnamon, Clove, Thyme, Nutmeg

PrunesPrunes

Black TeaBlack Tea

BerriesBerries Especially Raspberry and CranberryEspecially Raspberry and Cranberry

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Benzoates: Benzoates: Mechanism of IntoleranceMechanism of Intolerance

Mechanism of intolerance is unknownMechanism of intolerance is unknown

Has been suggested to involve inhibition of the Has been suggested to involve inhibition of the cyclo-oxygenase pathway since a significant cyclo-oxygenase pathway since a significant number of benzoate sensitive people are also number of benzoate sensitive people are also sensitive to aspirinsensitive to aspirin

There may be a similarity in sensitivity to:There may be a similarity in sensitivity to:

Tartrazine and other azo dyesTartrazine and other azo dyes

SorbatesSorbates

SalicylatesSalicylates

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Monosodium Glutamate (MSG)Monosodium Glutamate (MSG)

Flavouring common in Chinese cooking Flavouring common in Chinese cooking and increasingly used to flavour Western and increasingly used to flavour Western foodsfoods

Sensitive individuals report a variety of Sensitive individuals report a variety of symptoms that are usually classified as symptoms that are usually classified as “Chinese Restaurant Syndrome” (also “Chinese Restaurant Syndrome” (also known as Kwok’s syndrome)known as Kwok’s syndrome)

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Most Frequently Reported Symptoms of Most Frequently Reported Symptoms of Sensitivity to Monosodium GlutamateSensitivity to Monosodium Glutamate

Headache, back of head and neckHeadache, back of head and neck

Numbness of faceNumbness of face

Tingling/burning of face and chestTingling/burning of face and chest

Tightness in chestTightness in chest

Rapid heartbeatRapid heartbeat

Nausea, diarrhea, stomach acheNausea, diarrhea, stomach ache

Weakness, balance problemsWeakness, balance problems

ConfusionConfusion

Blurred visionBlurred vision

Chills, shakes, perspirationChills, shakes, perspiration

Difficulty breathingDifficulty breathing

Asthma in asthmaticsAsthma in asthmatics

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MSG SensitivityMSG Sensitivity

Experts are widely divided on the subject of Experts are widely divided on the subject of MSG sensitivityMSG sensitivity

One review “led to the conclusion that One review “led to the conclusion that ‘Chinese Restaurant Syndrome’ is an ‘Chinese Restaurant Syndrome’ is an anecdote applied to a variety of anecdote applied to a variety of postprandial illnesses”postprandial illnesses”

Some clinicians have estimated that the Some clinicians have estimated that the prevalence of “Chinese Restaurant prevalence of “Chinese Restaurant Syndrome” may be as high 1.8% of the Syndrome” may be as high 1.8% of the adult populationadult population

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Proposed Mechanism of Action of Proposed Mechanism of Action of MSGMSG

MSG is the sodium salt of glutamic acidMSG is the sodium salt of glutamic acid

Glutamic ions are the active ingredients in MSGGlutamic ions are the active ingredients in MSG

Human plasma glutamate levels after a dose of Human plasma glutamate levels after a dose of MSG (0.1 g/kg body weight) can increase to levels MSG (0.1 g/kg body weight) can increase to levels greater than 15 times the basal concentration rate greater than 15 times the basal concentration rate in one hourin one hour

Glutamate acts as a precursor for the Glutamate acts as a precursor for the neurotransmitter acetylcholine (as well as a neurotransmitter acetylcholine (as well as a number of other physiological chemicals in the number of other physiological chemicals in the body)body)

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Proposed Mechanism of Action of MSG: Proposed Mechanism of Action of MSG: Acetylcholine toxicityAcetylcholine toxicity

Acetylcholine reaches toxic levels in a very short Acetylcholine reaches toxic levels in a very short period of timeperiod of time

Acts on the brain and central nervous systemActs on the brain and central nervous system

Symptoms ascribed to MSG sensitivity may be Symptoms ascribed to MSG sensitivity may be caused by excessive levels of neurotransmitters caused by excessive levels of neurotransmitters such as acetylcholinesuch as acetylcholine

However, correlation between plasma levels and However, correlation between plasma levels and symptoms has not been shownsymptoms has not been shown

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Characteristics of MSG SensitivityCharacteristics of MSG Sensitivity

Vitamin B6 (pyridoxine) deficiency may occur in Vitamin B6 (pyridoxine) deficiency may occur in some MSG sensitive peoplesome MSG sensitive people

Alcohol may increase the rate of absorption of Alcohol may increase the rate of absorption of MSG and increase the MSG and increase the severityseverity and and rate of onsetrate of onset of of symptomssymptoms

Symptoms usually occur about 30 minutes after Symptoms usually occur about 30 minutes after eating a meal high in MSGeating a meal high in MSG

Asthma occurs 1 to 2 hours after MSG ingestion, Asthma occurs 1 to 2 hours after MSG ingestion, and even as long as 12 hours laterand even as long as 12 hours later

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Sources of MSGSources of MSG

Present in many flavouring mixtures:Present in many flavouring mixtures:

AccentAccent ZestZest

Gourmet powderGourmet powder GlutaveneGlutavene

GlutacylGlutacyl Chinese seasoningChinese seasoning

SubuSubu VetsinVetsin

AjinomotoAjinomoto Kombu extractKombu extract

Mei-jingMei-jing Wei-jingWei-jing

RL-50RL-50

Hydrolysed vegetable protein (HVP)Hydrolysed vegetable protein (HVP)

Hydrolysed plant protein (HPP)Hydrolysed plant protein (HPP)

““Natural flavour” (may be HVP)Natural flavour” (may be HVP)

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Sources of MSGSources of MSG

Used as a flavouring in foods, especially in Used as a flavouring in foods, especially in Chinese cooking, in canned foods (e.g. soups), and Chinese cooking, in canned foods (e.g. soups), and restaurant mealsrestaurant meals

Some sensitive individuals will also react to Some sensitive individuals will also react to monopotassium glutamatemonopotassium glutamate

Several foods, such as tomato, mushrooms, and Several foods, such as tomato, mushrooms, and cheese contain natural glutamatescheese contain natural glutamates

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Nitrate and Nitrite SensitivityNitrate and Nitrite Sensitivity Nitrates and nitrites are used in foods as Nitrates and nitrites are used in foods as

preservativespreservatives

Particularly protective against Particularly protective against Clostridium Clostridium botulinumbotulinum

Impart flavour and color to manufactured foods, Impart flavour and color to manufactured foods, especially meatespecially meat

SymptomsSymptoms

Reports of headache in sensitive individualsReports of headache in sensitive individuals

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Nitrates and Nitrites in FoodsNitrates and Nitrites in Foods

Labels list sodium nitrate, potassium nitrate, Labels list sodium nitrate, potassium nitrate, sodium nitrite, and potassium nitrite in sodium nitrite, and potassium nitrite in manufactured foodsmanufactured foods

Present at high levels in processed meats:Present at high levels in processed meats:

• • PepperoniPepperoni • • FrankfurtersFrankfurters

• • Hot Dog WienersHot Dog Wieners • • SalamiSalami

• • BolognaBologna • • Other Luncheon MeatsOther Luncheon Meats

• • BaconBacon • • HamHam

• • Smoked FishSmoked Fish • • Some Imported CheesesSome Imported Cheeses

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Nitrates in Plant FoodsNitrates in Plant Foods

Nitrates occur naturally in plants: the major source Nitrates occur naturally in plants: the major source is nitrate-containing fertilizersis nitrate-containing fertilizers

Some species of plants tend to accumulate nitrates Some species of plants tend to accumulate nitrates more than others:more than others:

• • SpinachSpinach • • CeleryCelery

• • BeetsBeets • • LettuceLettuce

• • RadishesRadishes • • CollardsCollards

• • Turnip GreensTurnip Greens • Aubergine• Aubergine


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