Transcript PowerPoint Slides

Trends in Allergies and
Intolerances in Nutrition and
Food Service
Janice M. Joneja, Ph.D., RD
10th Annual Regional Nutrition and Food Service Conference
Edmonton 2006
Progress in the Past 5 Years
Nearly 4% of North Americans have food allergies, many
more than recorded in the past
– Incidence of food allergy much higher in children than adults
(>8% compared to <2%)
Prevalence of peanut allergy doubled in American
children younger than 5 years of age in the past 5 years
Incidence of food intolerances estimated to be up to 50%
of the population, but accurate figures are not available
because of the lack of appropriate tests
– Incidence of food intolerances much higher in adults than in
children
Many food allergens have been characterized at the
molecular level, leading to increased understanding of the
causes of many allergic disorders
2
Management of Food Allergies and Intolerances
Management of food sensitivities consists of:
– Accurate identification of the food causing the
problem
– Educating clients on how to avoid relevant
allergens and intolerance triggers in foods
– Formulating appropriate diets to avoid the culprit
foods and replacing them with foods of equivalent
nutritional value
– Educating parents in measures to avoid
sensitization of their at-risk babies
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The Allergic Diathesis
Atopic dermatitis
(Eczema)
.
Sleep deprivation
Gastrointestinal
symptoms
Irritability
Mental fogginess
Fatigue
Food Allergy
Asthma
(cough;
wheeze)
Anaphylaxis
Allergic
rhinoconjunctivitis
(hay fever)
4
Food Allergy
Response of the
Immune System
Priority Food Allergens In Canada
Peanuts
Tree nuts (almonds, Brazil nuts, cashews, hazelnuts
(filberts), macadamia nuts, pecans, pinenuts, pistachios,
walnuts)
Sesame seeds
Milk
Eggs
Fish
Shellfish (e.g. clams, mussels, oysters, scallops and
crustaceans (e.g. crab, crayfish, lobster, shrimp) )
Soy
Wheat
Sulphites
These Priority Allergens account for more than 95% of
severe adverse reactions related to food allergens
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Additional Factors Involved in Symptoms
of Food Sensitivity
Increased permeability of the digestive tract
(leaky gut)
– Inflammation:
Infection
Allergy
Autoimmune disease
Other diseases
– Immaturity (in infants)
– Alcohol consumption
Physical exertion:
Exercise-induced anaphylaxis
7
Additional Factors Involved in
Symptoms of Food Sensitivity
Stress
Eating several different allergenic foods at the
same time
Other allergies occurring at the same time
(e.g. hay fever, asthma)
8
Classification of Food Allergens
[Sampson 2003]:
Class 1:
– Direct sensitization via the gastrointestinal tract
after ingestion
– Water-soluble proteins or glycoproteins
– Stable to heat, proteases, and acid
– Many are lipid transfer proteins
Class 2:
– Sensitization by inhalation of air-borne allergen
– Cross-reaction to foods containing structurally
identical proteins
– Heat labile
– Many are pathogenesis-related proteins
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Oral Allergy Syndrome
(OAS)
OAS refers to clinical symptoms in the
mucosa of the mouth and throat that:
Result from direct contact with a food allergen
In an individual who also exhibits allergy to
inhaled allergens.
Usually pollens (pollinosis) are the primary
allergens
Pollens usually trigger rhinitis or asthma
Occurs most frequently in adults
10
Oral Allergy Syndrome
Characteristics
Inhaled pollen allergens sensitize tissues of the
upper respiratory tract
Tissues of the respiratory tract are adjacent to oral
tissues, and the mucosa is continuous
Sensitization of one leads to sensitization of the
other
OAS symptoms are mild in contrast to primary
food allergens and occur only in and around the
mouth and in the throat
11
Oral Allergy Syndrome
The foods cause symptoms in the oral cavity
and local tissues immediately on contact:
–
–
–
–
–
Swelling
Throat tightening
Tingling
Itching
“Blistering”
Foods most frequently associated with OAS
are mainly fruits, a few vegetables, and nuts
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Oral Allergy Syndrome
Allergens
Pollens and foods that cause OAS are usually
botanically unrelated
Occurs most frequently in persons allergic to birch
and alder pollens
Also occurs with allergy to:
– Ragweed pollen
– Mugwort pollen
– Grass pollens
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Oral Allergy Syndrome
Cross-reacting allergens
Birch pollens with:
–
–
–
–
–
–
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–
–
–
–
–
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Apple
Stone Fruits (Apricot, Peach, Nectarine, Plum, Cherry)
Kiwi Fruit
Orange
- Peanut
- Almond
Melon
- Hazelnut
- Walnut
Watermelon
- Carrot
- Anise
Potato
- Celery
- Caraway seed
Tomato
- Parsnip
Green pepper
- Parsley
Cumin
- Beans
Coriander
- Peas
Dill
- Lentils
Sunflower seed
- Soy
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Oral Allergy Syndrome
Cross-reacting allergens
Ragweed pollen with:
– Banana
– Cantaloupe
– Honeydew
– Watermelon
– Other Melons
– Zucchini (Courgette)
– Cucumber
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Expression of OAS Symptoms
Oral reactivity to the food significantly
decreases when food is cooked
Reactivity of the antigen depends on
ripeness
– Antigen becomes more potent as the plant
material ages
People differ in the foods which trigger
OAS, even when they are allergic to the
cross-reacting pollens
– Foods contain an antigen that is structurally
similar to the allergenic pollen, but not all
people will develop OAS to all foods having that
antigen
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Identification of Foods Responsible
for OAS Symptoms
Skin tests will identify the allergenic plant pollen
Skin testing has not been successful in
identifying persons who react to cross-reacting
food antigens
– Plant antigens are unstable and do not survive the
process of antigen preparation
– Crushing plant material leads to release of phenols
and degradative enzymes
Prick + prick technique are more reliable than
standard skin tests
– Lancet is inserted in raw fruit or vegetable, withdrawn
and then used to prick the person’s skin
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Latex-Fruit Syndrome
Allergy to latex often starts as:
Contact allergy to a latex protein, usually
through:
– Abraded (non-intact) skin
– Mucous membrane
– Exposed tissue (e.g. during surgery)
Inhalant allergy:
– Inhaled powder from latex gloves
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Latex Allergy
Cross-reacting allergens
As antigen comes into contact with
immune cells, repeated exposure leads to
IgE mediated allergy
Proteins in foods with the same structure
as proteins in latex trigger the same IgE
response when they are eaten
In extreme cases can cause anaphylactic
reaction
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Latex Allergy
Related foods
Examples of foods that have been shown to
contain proteins similar in structure to latex:
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Banana
Citrus Fruits
Kiwi Fruit
Fig
Passion Fruit
Grapes
- Mango
- Melon
- Pineapple
- Papaya
- Peach
- Potato
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Tomato
Celery
Avocado
Tree Nuts
Chestnut
Peanut
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Common allergens in unrelated plant
materials: Summary
OAS and latex allergy are examples of
conditions in which common antigens,
expressed in botanically unrelated plants,
are capable of eliciting a hypersensitivity
reaction
In practice, when a specific plant food
elicits an allergic response, foods in the
same botanic family rarely elicit allergy
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Food Intolerances
Biochemical and Physiological
Responses
Symptoms of Carbohydrate Intolerance
Watery loose stool (diarrhea)
Abdominal bloating and pressure
Cramping pain in abdomen
Flatulence
Vomiting
Poor weight gain
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Cause of Carbohydrate
Intolerance
Lack of the enzyme that digests the
carbohydrate
Lactose intolerance is due to the lack of
lactase:
– Milk sugar (lactose) is not digested
Sucrose intolerance is lack of the enzyme
sucrase
– Sucrose (table sugar; syrup of all types; some
fruits) is not digested
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Symptoms of Carbohydrate Intolerance
Reddening and soreness of skin around the
anus and on the buttocks due to acid (pH less
than 6) stool in children.
– Adults rarely develop high acid stool
Abdominal fullness, bloating, and cramping
within 5-30 minutes after eating
Diarrhea
Lactose intolerance is the most common
condition
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Management of Lactose Intolerance
Only the milk sugar, lactose, needs to be avoided
This is not a milk allergy:
– Milk proteins are tolerated
Lactose occurs in the whey (liquid) fraction of milk
Milk products free from lactose and free from whey are safe
These foods include:
– Milk treated with lactase (Lactaid; Lacteeze)
– Hard cheeses (whey is removed; casein remains and is
fermented to form cheese)
– Many people tolerate yogurt, where lactose is broken down
by bacterial enzymes
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Reactive Chemicals in Foods
 May act on the body in two ways:
– chemical acts directly on body tissues rather
like a drug
– chemical reacts with a system (stops or
enhances the process) that acts on the body
tissue
Symptoms occur when the body is unable
to get rid of the chemical quickly enough
– The level in the body rises and the symptoms
that develop are due to the excess
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Histamine
 Histamine reactions can be clinically
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indistinguishable from food allergy
Hives, facial swelling, and headaches are examples
of histamine excess
Tests for food allergy are usually negative
Histamine sensitivity is becoming recognized as a
disease entity quite distinct from allergy
Sensitivity may be deficiency in the enzymes that
break down excess histamine
Histamine intolerance can exacerbate allergy to the
extent of eliciting an anaphylactic reaction when
the two conditions occur together
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Sources of Histamine in Foods
Fermented foods:
– Microbial activity on proteins produces histamine
Examples:
Cheese
Processed meats and sausages:
Salami
Bologna
Pepperoni
Vinegar and foods containing vinegar:
Pickles
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Sources of Histamine in Foods
Fermented beverages:
– Wine
– Beer, ale, lager
Fish and shellfish:
– Incorrectly stored
– Bacteria in the intestine of the fish start to break
down fish protein
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Sources of Histamine in Foods

Some foods contain high levels of histamine
naturally, especially:
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Spinach
Eggplant
Berries (strawberries and raspberries)
Tomato
Citrus fruits (orange; lemon; lime; grapefruit)
Some foods may release histamine by a
mechanism which is only partially understood
example: egg white
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Other Sources of Histamine
Micro-organisms in the body:
– Certain types of bacteria in the large bowel
use undigested food material for their
reproduction and growth
– People with these micro-organisms absorb
histamine from their own intestine
– It is possible that probiotic bacteria could be
used to displace these strains
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Tyramine sensitivity
Symptoms when tyramine-rich foods are eaten:
– Sharp rise in blood pressure
– Headache
Caused by:
 Deficiency in the enzymes that break down
excess tyramine
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Tyramine in Foods
Formed by microbial action in food
preparation:
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–
cheese
wine
yeast extract
vinegar
Small amounts occur naturally in some
foods:
– chicken liver
– avocado
– banana
- eggplant
- tomato
- plum
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Sensitivity to Food Additives
Characteristics common to persons
sensitive to food additives:
– History of asthma and hay fever
– Occasionally hives and facial swelling
– Aspirin sensitive
35
Additives Most Frequently Causing
Intolerances
Tartrazine (and other artificial food colours)
Preservatives:
– Sulphites
– Benzoates
– Sorbates
Monosodium glutamate (MSG)
Nitrates and nitrites
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Symptoms of Tartrazine Sensitivity
Asthma in asthmatics
Urticaria
Angioedema
Nausea
Migraine headaches
Evidence of hyperactivity in children
Excess tartrazine may increase levels of
inflammatory mediators in allergy, such as:
– leukotrienes – important mediators in asthma
– histamine
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Foods Frequently Containing Tartrazine
Soft drinks
Liqueurs and cordials
Candy and confectionery
Ready-to-eat cereals
Jams and jellies
Ice cream, sherbet, milk shakes
Commercial gravies and soup mixes
Flavor packets
Pickles, relish, salad dressings
Prepared baked goods
Smoked fish and fish products
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Foods Frequently Containing
Tartrazine
Snack foods
Meal replacements
Any food containing “artificial color” may
contain tartrazine unless it is labeled
“tartrazine free”
Non-food items:
Medications (prescription and OTC)
Vitamin and mineral supplements
Toiletries and cosmetics
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Sulphite Sensitivity
Most common in asthmatics
Steroid-dependent asthmatics are most at risk
Adverse reactions to sulphites is estimated to be as
high as 1% of the U.S. population
Sulphite sensitivity in non-asthmatics is considered to
be quite rare
Symptoms occur in most organ systems:
– Lungs
– Gastrointestinal tract
– Skin and mucous membranes
– Life-threatening anaphylactic reactions in
asthmatics have been recorded, but occur very
rarely.
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Symptoms Reported in Sulphite
Sensitivity
Urticaria (hives)
Angioedema (swelling, especially of the
mouth and face)
Contact dermatitis
Anaphylaxis (in asthmatics)
Anaphylactoid reaction (non-asthmatics)
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Forms of Sulphites Permitted in
Foods
Sulphites are permitted in the form of:
– Sodium metabisulphite
– Potassium metabisulphite
– Sodium bisulphite
– Potassium bisulphite
– Sodium sulphite
– Sodium dithionite
– Sulphurous acid
– Sulphur dioxide
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Forms of Sulphites Permitted in
Foods
Use of sulphites on fresh fruits and vegetables not
allowed except on sliced raw potatoes and raw grapes
Sulphites are not allowed on raw foods in salad bars
or for sale in markets, with the above exceptions
U.S. government regulations require sulphites in
excess of 10 ppm in manufactured foods and
beverages, including alcoholic beverages, to be listed
on labels
Sulphites are permitted in a wide rage of dried,
frozen, and processed foods, sweeteners, and snack
foods
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Sulphite Sensitivity
There is no evidence that avoiding all sources of
dietary sulphites improves asthma
Exposure to sulphiting agents poses very little risk for
individuals who are not sensitive to sulphites
Sulphites in foods are not denatured by cooking
Sulphites avidly bind to several substances in foods,
such as protein, starch, and sugars. They are not
removed by washing
Sulphates do not cause the same adverse reactions
as sulphites. They are inert in the body and need not
be avoided by people who are sensitive to sulphites
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Benzoate Intolerance
Symptoms
Reported to induce:
– Urticaria
– Angioedema
– Asthma
– Rhinitis
– Purpura (allergic vasculitis)
– Hyperactivity in children
May lead to increase in histamine
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Benzoates and Parabens:
Use in Foods
One of the most commonly used food
additives worldwide
Benzoic acid and sodium benzoate
(benzoates) are used as antibacterial and
antimycotic agents in foods and beverages
Benzoates are most effective as preserving
agents at an acidic pH
Benzoyl peroxide is used as a bleaching
agent, especially in white flour, white bread,
and some white Italian cheeses
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Benzoates
Naturally occurring
Benzoates occur widely in nature as simple
salts (sodium, potassium), esters, and amides
Natural benzoates are present at the highest
levels in:
– Cinnamon, Clove, Anise, Nutmeg
– Prunes
– Black Tea
– Berries
Especially Raspberry and Cranberry
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Monosodium Glutamate (MSG)
Flavouring common in Chinese cooking
and increasingly used to flavour
Western foods
Sensitive individuals report a variety of
symptoms that are usually classified as
“Chinese Restaurant Syndrome” (also
known as Kwok’s syndrome)
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Most Frequently Reported Symptoms of
Sensitivity to Monosodium Glutamate
– Headache, back of head and neck
– Numbness of face
– Tingling/burning of face and chest
– Tightness in chest
– Rapid heartbeat
– Nausea, diarrhea, stomach ache
– Weakness, balance problems
– Confusion
– Blurred vision
– Chills, shakes, perspiration
– Difficulty breathing
– Asthma in asthmatics
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MSG Sensitivity
Experts are widely divided on the
subject of MSG sensitivity
One review “led to the conclusion that
‘Chinese Restaurant Syndrome’ is an
anecdote applied to a variety of
postprandial illnesses”
Some clinicians have estimated that the
prevalence of “Chinese Restaurant
Syndrome” may be as high 1.8% of the
adult population
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Characteristics of MSG Sensitivity
Alcohol may increase the rate of absorption
of MSG and increase the severity and rate of
onset of symptoms
Symptoms usually occur about 30 minutes
after eating a meal high in MSG
Asthma occurs 1 to 2 hours after MSG
ingestion, and even as long as 12 hours later
Vitamin B6 (pyridoxine) deficiency may be a
factor in some MSG sensitive people
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Sources of MSG
Present in many flavouring mixtures:
Accent
Zest
Gourmet powder
Glutavene
Glutacyl
Chinese seasoning
Subu
Vetsin
Ajinomoto
Kombu extract
Mei-jing
Wei-jing
RL-50
Hydrolysed vegetable protein (HVP)
Hydrolysed plant protein (HPP)
“Natural flavour” (may be HVP)
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Sources of MSG
Used as a flavouring in foods, especially in
Chinese cooking, in canned foods (e.g.
soups), and restaurant meals
Some sensitive individuals will also react to
monopotassium glutamate
Several foods, such as tomato, mushrooms,
and cheese contain natural glutamates
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Nitrate and Nitrite Sensitivity
Nitrates and nitrites are used in foods as
preservatives
Particularly protective against Clostridium
botulinum
Impart flavour and preserve colour in
manufactured foods, especially meats
Symptoms
Reports of headache in sensitive individuals
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Nitrates and Nitrites in Foods
Labels list sodium nitrate, potassium nitrate,
sodium nitrite, and potassium nitrite in
manufactured foods
Present at high levels in processed meats:
• Pepperoni
• Frankfurters
• Hot Dog Wieners
• Salami
• Bologna
• Other Luncheon Meats
• Bacon
• Ham
• Smoked Fish
• Some Imported Cheeses
55
Nitrates in Plant Foods
Nitrates occur naturally in plants: the major
source is nitrate-containing fertilizers
Some species of plants tend to accumulate
nitrates more than others:
• Spinach
• Celery
• Beets
• Lettuce
• Radishes
• Collards
• Turnip Greens
• Eggplant
56
Summary
Food allergy is most prevalent in babies and children
Food intolerances predominate in adults
Infant onset food allergy is mostly due to Class 1
allergens
– Sensitization is by ingestion of allergen
Adult onset food allergy mostly due to Class 2 allergens
– Sensitization by allergen inhalation or contact
Food allergy: must avoid all sources of the allergen
Food intolerance: dose related
Several additional factors sometimes required to elicit
symptoms
Food intolerance can exacerbate food allergy
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