3. Composition of Carbohydrates
Come from plant foods
Cheapest and most plentiful of
all nutrients
Foods which contain
carbohydrates, are called energy
foods
All of the energy obtained from
food starts with a single sugar unit
- glucose. Some plants store
energy for later use by combining
sugars to make starch.
7. Carbohydrates – Cellulose / Fibre
Cellulose or Dietary Fibre is found
in
whole cereals
wholemeal bread
outer skins of fruit and vegetables
brown rice
Oatmeal
In refined foods the dietary fibre is
removed during processing e.g.
wholemeal flour contains fibre but
white flour does not.
9. Functions of Carbohydrates
Carbohydrates provides the body with
heat and energy
Fibre helps the movement of food through
the intestine.
Fibre rich and starchy foods provide a "full
feeling“
Pectin helps jam to set
10. RDA
Nutritionists believe that the amount of
sugar eaten in the western countries
needs to be decreased and the amount of
fibre needs to be increased.
The Recommended Dietary Allowance
(RDA) of fibre is now 30g per day. We in
the western world eat about half the
recommended amount-15g per day.
11. Fats
Fat is an important
nutrient because it
gives us energy
The body stores
energy as a layer of
fat under the skin.
This is called adipose
tissue
12. Composition of Fats
Fats are made from
glycerol and fatty acids
Each glycerol is attached
to three fatty acids
Glycerol and fatty acids
contain the elements
carbon, hydrogen, and
oxygen
Fats contain a lot of
carbon. This is why they
give us so much energy.
1 gram of fat gives us 9
kilocalories
13. Classification of Fats
Fats are classified into two
groups:
Saturated Fats
come mainly from an animal
source such as meat, eggs,
milk and dairy produce e.g.
cream and butter. There is a
lot of saturated fat in butter
and lard
Unsaturated Fats
come mainly from plant and
fish sources such as peas,
beans and lentils, whole
cereals, nuts, cooking oil,
polyunsaturated margarine
and oily fish
14. Functions of Fats
Fat insulates the body. A layer of fat
under the skin prevents heat loss from the
body.
Fat protects the delicate organs such as
the kidneys and nerves. A layer of fat
surrounds them.
Fats provide the body with heat and
energy. This helps to keep the body at the
correct temperature (37o C).
Fat is a source of the fat-soluble vitamins
15. RDA of Fats
It is recommended that we eat 50%
saturated fat and 50% unsaturated fat in
our diet
People in the western world eat too much
saturated fat and it is recommended that
we cut down on our intake
We should also increase our intake of
unsaturated fats
16. To cut down on Saturated Fats
Grill rather than fry.
Use vegetable oil instead of hard fats for
frying.
Remove visible fat from meat.
Look for hidden fats in the diet e.g. pastries
and crisps.
Use low fat milk, cheese, yoghurt and
mayonnaise
17. Protein
Our bodies are made up of billions of cells,
which contain protein
Throughout our lives cells wear out and
are replaced
All the material for new cells comes from
food
The main nutrient involved in the building
of new cells and replacing of worn cells is
protein
18. Composition of Proteins
Proteins are made up of small units called
amino acids
The amino acids, which the body cannot
make, are known as essential amino acids
Adults need 8 and children need 10
essential amino acids.
19. Composition of Proteins
Proteins are broken down
into amino acids in the
digestive system
Amino acids are smallest
units of Protein. They can
then be used to build up
different proteins for the
formation of new cells in
the body
Amino acids are made up
of the elements carbon,
hydrogen, oxygen and
nitrogen
20. Classification of Proteins
Classified into two groups:
HBV and LBV
High Biological Value Proteins
come mainly from animal
foods such as meat, fish,
eggs, cheese and milk
Low Biological Value Proteins
come mainly from plant foods
such as peas, beans and
lentils, whole cereals and nuts.
These foods also contain fibre
and are low in fat
21. Functions of Proteins
The functions of proteins are:
Growth of new cells such as skin hair
and blood.
Repair of damaged cells.
Production of heat and energy.
Manufacture of important body chemicals
such as enzymes, hormones and
antibodies.
22. RDA of Proteins
The RDA of protein
depends on your
body weight
For every kilogram of
body weight one gram
of protein per day is
needed, e.g. if you
weigh 60 kg you need
60 g of protein per
day
23. Vitamins
The word "vitamin" comes from vita, the
Latin for "life“
Everybody must eat a certain amount of
vitamins to stay healthy
Vitamins are chemicals found in very small
amounts in many different foods. Tiny
quantities are enough for the needs of the
body
If people live on a very limited range of
foods they may not get their proper share
of vitamins
24. Classification of Vitamins
Vitamins, of which there
are 14, are classified
into two main groups:
Water soluble and Fat
soluble
Fat soluble – stored in
bodies fat tissue
A, D, E & K
Water soluble – not
stored in the body
B vitamins, folic acid &
vitamin C
25. Vitamins
Fat soluble:
Vitamin A - needed for healthy
vision, bone growth,
reproduction and the immune
system
found in dark green, orange and
yellow vegetables, such as
spinach, carrots, broccoli, mangos,
apricots, vegetable soup and
tomato juice.
It is also found in meat and dairy
products such as liver, beef,
chicken, whole milk and eggs.
26. Vitamins
Fat soluble:
Vitamin D - controls the absorption of
calcium and phosphorus, which are
essential for bone growth and
development
sardines and tuna, liver, egg yolks, some
breakfast cereals and vitamin D-fortified
milk. Vitamin D can also be made when
the skin is exposed to sunlight
27. Vitamins
Water soluble:
Vitamin C - helps to
maintain skin integrity,
absorb iron from the gut
and heal wounds, and is
important in immune
functions
Vitamin C is found in citrus
fruit and juices, tomatoes,
spinach, potatoes, berries,
green and red peppers,
and broccoli
28. Vitamins
Water soluble:
Folate (folic acid), also called vitamin B9 is
essential for the normal formation of the
red blood cells, protein metabolism,
growth and cell division
Food sources include liver, citrus juices
and fruits, beans, nuts, seeds, liver, dark
green leafy vegetables.
29. Minerals
The human body requires about 20 mineral
elements
Each has a specific function and is found in
certain foods
A good varied diet should supply all essential
minerals
Some minerals are described as trace
elements because the are required in smaller
amounts
Minerals are lost into the water during cooking
30. Macrominerals
Calcium - for muscle and digestive system health,
builds bone, neutralizes acidity, clears toxins, helps
blood stream
Found in milk, cheese, green leafy vegetables
Potassium – for growth of lean tissue
Found in bananas
Sodium – regulation of water balance in the blood
Found in table salt, bacon, snack foods
Sulfur
Magnesium
Phosphorus
31. Trace Minerals
Iodine – Needed for the formation of
thyroxine, a hormone in the thyroid gland which
controls metabolism
Found in vegetables and sea fish
Iron – Needed to make red blood cells
Found in red meat, liver & cabbage
Manganese – Processing of oxygen
Zinc
Cobalt
Copper
32. Water
Water is absolutely
essential to life. Over
70% of the human body
is made up of water. It is
found in:
Muscles
Saliva
Blood
Digestive Juices
Mucus
Sweat
33. Composition of Water
Water contains the elements hydrogen
and oxygen
They are present in the ratio 2:1, two parts
hydrogen to one part oxygen
Pure water freezes at 0C and boils at
100C
34. Sources of Water
The main sources of water
are drinking water and
beverages like tea, coffee
and alcoholic drinks
Water is also present in
many other foods like meat
and fish
Fruits and green vegetables
are high in water. Almost all
foods contain water, except
those with a high fat content
(butter), and dry foods
(sugar and flour)
35. Functions of Water
It is the chief component of all body fluids.
It helps dissolve foods and aids digestion.
It helps remove waste material from the body.
It regulates body temperature by perspiration.
It is a source of dissolved minerals such as
flourine and calcium.
It keeps the body fluids liquid so that they may
flow easily.
36. RDA of Water
As 2-2.5 litres of water
are lost daily by
excretion, and
perspiration, an equal
amount is required daily
by the body to avoid
dehydration
1.5 litres of water is
obtained from beverages
and 0.8 from food.
