Essential Food Elements
By
Dr Hamda Qotba, B.Med.Sc, M.D, ABCM
2004
Dr. Hamda Qotba
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Objectives
1) Introduction of important
terminology
2) To know the function, source,
structure of carbohydrates,
proteins, and fat
3) Side effects of excess and
insufficient intake of EFE
2004
Dr. Hamda Qotba
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Terminology you have to know
Nutrition:
Process by which living organism
receives material and uses them to
promote it’s vital activities
Nutrient:
Any substance which is digested and
absorbed to promote body function
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Dr. Hamda Qotba
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Diet:
Selection of food which is normally
eaten by person or population
Food:
Substance when eaten , digested,
absorbed provide at least one
nutrient
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Dr. Hamda Qotba
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Balanced diet :
Diet that provide adequate amount of all
nutrients
Malnutrition:
Caused by incorrect amount of nutrient
intake
Nutritional status:
Health status that produced by balanced
between requirements and intake
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Dr. Hamda Qotba
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Nutritional assessment:
Measurement of nutritional status by
anthropometrics , biochemical
data, dietary history
Dietitian:
Persons who applies science of
nutrition to people in health and
disease
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Dr. Hamda Qotba
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Metabolism :
Changes taking place in the body as
result of body activity
Anabolism:
Complex molecules are synthesized
from simpler ones
Catabolism:
Complex molecules are broken to
simpler ones
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Dr. Hamda Qotba
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Carbohydrates
• Starch , sugar
• Broken in the body to produce heat
and energy
• Oxidation of carbohydrate in the
body produce CO2 and H2O
• 1g ---- 16 kj (4kcal)
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Dr. Hamda Qotba
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Structure
• Monosaccharides:
Glucose , fructose and galactose
• Disaccharides:
Sucrose , lactose and maltose
• Polysaccharides:
Amylose: straight chain of 70-350
glucose
Amylopectin: branched chain of
100000 glucose
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Dr. Hamda Qotba
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Sources of carbohydrates
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Glucose ------ fruits
fructose ------ honey
sucrose ------ beet, cane
lactose ------- milk
Galactose ---- digestion of lactose
maltose ------ sprouting grains
starch ------ grains, unripe ft+veg.
Glycogen---- liver, muscles
Cellulose ------ cereals, veg.,
cell wall as fiber
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Properties & uses
• Sweetness differs fructose  lactose
• Glucose --- added for food when
high energy required
• Fructose --- sweetener in diabetes
• Sucrose -- sweetener & preservative
• Glucose syrup ---- jam
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Dr. Hamda Qotba
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Digestion & Absorption
• Starch pancreatic amylase maltotriose
• Disaccharidases sucrose, maltose, lactose
monosaccharide
carbohydrate are absorbed in the single form
• Absorbed by intestinal villi then travel by
blood stream to the liver through the
portal vein
2004
Dr. Hamda Qotba
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Utilization
1. Used as fuel to produce energy for
cell activity
2. Glycogen (glucose, galactose, fructose)
is synthesized in liver and muscle
and it’s used for muscular work
3. Converted into fat when liver and
muscle are full with glycogen
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Dr. Hamda Qotba
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Blood sugar level & Hormonal
control
• 65-180 mg/dl
• Insulin β pancreatic cell assessing
passage of glucose to cell
• Adrenaline adrenal medulla glucose
from the break down of glycogen
in liver
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• Glucagon  pancreatic cell glucose
from the break down of glycogen
in liver
• Growth hormone pituitary gland
antagonize insulin
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Intake
• Traditional food consists mainly of
carbohydrate like rice, wheat, corn, honey,
jam, fruits and veg.
• Excess intake
obesity
• lack intake
ketosis
• lack intake
depletion of body tissue
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Dr. Hamda Qotba
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Fat
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Carbon, Hydrogen, and Oxygen
Glycerol + 3 fatty acid triglyceride
Fatty acid e.g stearic, palmitic, oleic
Saturated = single bond, stable
Unsaturated = double bond, less stable
Bond converted from double
Unsaturated to single
Saturated=hydrogenation
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Hydrogenation
• Change chemical and physical ->harder,
raise melting point
• Saturated= single bond (palmitic,
stearic[lard] )
• Monosaturated= 1double bond
(oleic[olive])
• Polyunsaturated= > 1double bond
(linoleic[corn])
More hydrogen is introduced chemically
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Dr. Hamda Qotba
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Rancidity & Solubility
• In dairy product is due to liberation
of free fatty acid as a result of
hydrolysis of triglyceride by bacteria.
• Non dairy product exposure to O2
cause oxidation
• Emulsion: suspension of minute
particle
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Sources
• Animal
high in cholesterol
(fat, butter, egg, milk)
• Vegetable
plant sterols that are poorly
absorbed by man, not cholesterol
(olive , cotton, corn)
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Dr. Hamda Qotba
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Digestion
• In the duodenum
fat pancreatic lipase
f.f.acid+monoglyceride
• Enter mucosal cell to form
triglycerides, combine with protein
and cholesterol to form lipoprotein
• The remainder are absorbed into
portal circulation as fatty acid and
glycerol
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Dr. Hamda Qotba
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Function
• Provide energy 37kj -> 9kcal/g
• Incorporation into body structure
brain and nervous system
• Protection cover vital organs
• Insulation prevent heat loss from the
body
• Satiety
• Fat soluble vitamins ADEK
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Stores & intake
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Under skin, around abdominal
organs
There’s no definite amount of fat
is known to maintain health
Food as fat source:
1. High fat sources= >10%
2. Moderate fat sources= 3-10%
3. Poor fat sources = <2%
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Dr. Hamda Qotba
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Essential fatty acid
• They are polyunsaturated fatty
acid needed for the body (linoliec,
linolenic, arachinodic)
• Deficiency due to malabsorption or
prolonged IV intake
• Vit. E important in preserving there
chemical structure
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• Cholesterol
synthesized in the liver, attach it
self to lipoprotein to be able to
transfer in the body
LDL bad cholesterol (<160mg/ml)
HDL good cholesterol (>40mg/ml)
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• Phospholipid
Fatty material, integral part of the
body (brain, nervous system)
Present in blood plasma
• Lipoprotein
Plasma protein in which fat combine
with them to be in the soluble form
in the plasma
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Proteins
• Principle constituent of the cell
• Composed of amino acid
• Animal synthesis protein from A.A
but not vice versa
• Plant synthesis A.A from CO2, H2O,
Nitrogen
• Protein is the only source of
nitrogen in the body
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• By shape fibrous, globular
• Protein in food like:
myosin meat
Albumin, vitellin egg
Casein milk
gluten wheat
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Essential Amino Acid
• A.A that the body are unable to
make or make in insufficient amount
Histidine lysine
methionine
Valine leucine
isoleucine
Tryptophan phenylalanine threonine
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• Biological value Protein food that
contain all A.A in the proportion needed
for man is said to be high biological
value (egg, human milk)
• Limiting A.A essential A.A that food lack
wheat
soya beans
maize
lysine
methionine
trypyophan
• This problem can be overcome by eating
food that contains needed A.A
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Dr. Hamda Qotba
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Function
• Replace protein loss (wear & tear )
• Produce new tissue (growth,
pregnancy)
• Manufacture o new protein (enzyme)
• Source of energy
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Nitrogen balance
• 6g protein 1g nitrogen
• To be in nitrogen balance
intake=output
• Normal lose 14g
• +ve nitrogen balance intake >loss
(growth)
• -ve nitrogen balance intake < loss
(burns)
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Digestion, absorption & excretion
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Stomach proteolytic enzyme large
polypeptides
Duodenum pancreatic enzyme
peptides+A.A
peptides+A.A enter the intestinal cell:
1. Build structural proteins
2. Converted to other A.A
3. Produce energy
Excreted by kidney in the form of urea
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Intake
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If Insufficient impair healing&
increase infection
Deficiency may arise as a result
of:
1.
2.
3.
4.
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If energy requirement increase
Burn , fracture, injuries
Failure to utilize protein
Excessive loss
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Protein Energy Malnutrition (PEM)
• Kwashiorkor
lack of protein, other energy
sources
• Result in growth retardation,
infection, slow recovery,
• Signs
edema, muscle wasting ,liver
enlargement, change in pigmentation
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Protein Energy Malnutrition (PEM)
• Marasmus
lack of energy and protein
• Sings
muscle wasting, loss of S.C fat, growth
retardation
Overcome by breast feeding, nutritional
supplement, nutrition education
and improve sanitation
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Dr. Hamda Qotba
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