2. Introduction
• Food-hypersensitivity reactions can either
involve:
• The immune system in which case it’s called a
‘food allergy’ or
• It does not involve the immune system and is
called ‘food intolerance’.
• A food intolerance is sometimes confused with or
mislabeled as a food allergy.
3.
4. Food Allergy
• A food allergy is an abnormal
reaction of the body's immune
system to a particular food.
• Food allergy, reactions caused
by the immune system, either
IgE antibody mediated or
delayed non-IgE mediated
allergy.
• Affects multiple body systems:
GI
Respiratory
Skin
Cardiovascular
• Exposure can cause serious
problems or death.
Common food allergies
• About 90% of food allergies
are caused by seven foods:
o cow’s milk
o hen’s eggs
o soybeans
o peanuts
o tree nuts – almond, brazil,
cashew and so on
o wheat
o fish and shellfish.
• The remaining 10% of
allergies are caused by a wide
variety of other foods.
5. Intolerance vs. Allergy
• Food Intolerance
– Reaction to the chemicals in food
– No immune system response
– No serious (life-threatening) side-effects
• Bloating, gas, abdominal discomfort.
6. What is food intolerance?
• Food intolerance, also known as non-IgE
mediated food hypersensitivity or non-allergic
food hypersensitivity,
• refers to difficulty in digesting certain foods.
• It is important to note that food intolerance is
different from food allergy.
• Food intolerances involve the digestive system.
• Food allergies involve the immune system.
7. • When ingestion of a particular food or food
additive causes unpleasant symptoms, a
person is said to be intolerant to that food.
• Symptoms occur as a result of either:
poor absorption from the intestine into the
bloodstream or
less commonly by the release of chemicals
within the body occurring as a result of
contact of the food with the body.
What is food intolerance?
8. Symptoms of food intolerance
• It can be difficult to determine whether the patient has a
food intolerance or an allergy because the signs and
symptoms often overlap.
• when it is an allergy, even small amounts result in
symptoms, as may be the case with peanuts. Whereas, with
food intolerance, tiny amounts will usually have no effect.
• The symptoms of food intolerance generally take longer to
emerge, compared to food allergies.
• onset typically occurs several hours after ingesting the
offending food or compound and may persist for several
hours or days.
9. • According to the Australian NSW Food Authority, the
following are the most common symptoms of food
intolerance:
• Bloating
• Migraines
• Headache
• Cough
• Runny nose
• Stomach ache
• Irritable bowel
• fatigue.
10. Causes of food intolerance
• There are many different types of food intolerances,
including:
Enzymatic - lactose intolerance.
Intolerance to a protein. Gluten (Celiac)
Pharmacologic reactions.
• Pharmacological intolerances involve reactions to certain
chemical naturally occurring foods such as:
Histamine containing foods such as cheese
food additives, especially the benzoate and sulphite
preservatives and monosodium gluatamate.
caffeine – in coffee, tea, and chocolates.
salicylate and glutamate
Toxin
11. Absence of an enzyme
• Nearly all foods require an enzyme for proper
digestion.
• According to the British Allergy Foundation, enzyme
deficiencies are a common cause of food intolerance.
• The most common type of enzymatic food intolerance
is lactose intolerance, which occurs because these
individuals have either too little or no lactase
• lactose intolerant: it can cause spasm, stomachache,
bloating, diarrhea, and gas.
• Researchers from Mary Bridge Children's Hospital and
Health Center USA , found that fructose intolerance is
common in children with recurrent or functional
abdominal pain.
12. Pharmacologic reactions.
Food chemical Dietary sources
Proposed mechanism of gastrointestinal
symptom provocation
Salicylates
Coffee, tea, green apples, banana,
lemon, plums, grapes, grapefruit,
tomato, carrots, cucumber, peas,
herbs and spices
Stimulates mast cells to overproduce leukotriene
metabolites which in turn may lead to pro-
inflammatory reactions and smooth muscle
contraction
Amines (e.g.
histamine)
cheese, cured and processed meat
products, tinned fish
Low amine oxidase activity in some individuals
limits detoxification of dietary histamine and
increased levels of histamine can increase smooth
muscle contractions
Glutamates
Tomato, cheese, stock cubes, yeast
extract
Unknown but exclusion of dietary additive
excitotoxins (including MSG) in IBS resolved >30%
of symptoms in 84% of patients
Caffeine
Coffee, tea, chocolate, cola drinks,
caffeine drinks
Stimulates central nervous system and increases
gastric juice secretion and colonic motor activity
possibly via gastrointestinal neuroendocrine
hormones (e.g. cholecystokinin, exorphin, gastrin
or motilin) but this is unknown
13. Diagnosing food intolerance
• Investigations may include blood and faecal tests,
endoscopy and/or radiological imaging to rule out any
organic disease.
• It is not easy to determine whether somebody has a
food intolerance or allergy because the signs and
symptoms often overlap.
• The doctor may recommend a skin test and/or a blood
test to rule out food allergy.
• Apart from lactose intolerance and celiac disease,
there is no accurate, reliable, and validated test to
identify food intolerance.
14. Food Exclusion, Symptom
Improvement and Dietary Challenge
• The best diagnostic tool is an exclusion diet, also
known as an elimination or diagnostic diet.
• Patients are advised to keep a diary and write
down which foods are eaten, what the symptoms
were like, and when they appeared.
• The data in the diary can help a dietician or
doctor identify which foods are causing adverse
reactions, and what steps to take.
• Exclusion diets are extremely useful in isolating
the culprit foods.
15. • In a typical exclusion diet, the suspected food is
removed from the diet for a set period, usually
between 2 weeks and 2 months.
• If during this period the adverse reactions resolve, it
becomes more likely that the culprit has been found.
• This can be further confirmed if it is then reintroduced
and symptoms return.
• It is important to emphasise that elimination diets
must only be undertaken for a short term, under strict
medical supervision.
• Prolonged restricted diets can lead to problems with
adequate nutrition, particularly in children.
16. Testing for Food
Intolerance ????
By taking a small, finger-
prick blood sample, it is
possible to measure food-
specific IgG antibodies in
your blood.
Your IgG antibody
readings are shown in your
personal Food Intolerance
Test results.
17. Treatment
• The best current treatment for food
intolerance is to either:
• avoid certain foods or
• eat them less often and in smaller amounts,
as well as
• taking supplements that may help digestion.
18. Tolerance can improve
• Some people find that if they stay off the
specific food for a while, they have no reaction
when eating it again - this is known as
tolerance.
• Maintaining tolerance is often a question of
knowing how long to abstain, and how much
of it to eat when it is being reintroduced.