Download In all animal and plants, food is used as follows

1
Minerals are inorganic substances which we need in very small amounts in our diet.
Some minerals needed for humans are:
Mineral
Why you need it
Iron
To make
haemoglobin, the
red pigment in
blood cells which
carries oxygen
For bone and teeth
formation
For making the
hormone thyroxin
Calcium
Iodine
Deficiency
symptoms
Anaemia caused by
a lack of
haemoglobin to
carry oxygen
Foods rich in it
Poor growth of
bones and teeth
Goitre
Milk, cheese and
egg
Sea food, table salt
Liver, lentils and
red meet
Iron: Part of the haemoglobin molecule, present in the red blood cells contains iron.
This mineral plays an important part in carrying out oxygen around the body. As red
blood cells break down, their iron is stored in the liver and used to make more
haemoglobin. However some iron is lost, and adults, need to take in some iron in the
diet (about 15 mg of iron each day). Iron is also needed in the muscles and for enzyme
systems in all the body cells. Red meat, especially liver and kidney, is the richest source
of iron in the diet, but eggs, groundnuts (nueces), bread, spinach, lentils and most green
vegetables are also important sources. If the diet is deficiency in iron, you may suffer
anaemia, in this case, insufficient haemoglobin is made and the oxygen carrying
capacity of the blood is reduced, you therefore feel more tired and weak.
Calcium: calcium in the form of calcium phosphate is deposited in the bones and teeth
to make them hard. It is present in blood plasma and plays an essential in normal blood
clotting. Calcium is also needed to for the chemical changes that make muscles contract
and for transmission of nerve impulses. The richest sources of calcium are milk, and
cheese, but calcium is also present in most foods in small quantities, and also in hard
water. Many calcium salts not soluble in water may pass through the alimentary canal
without being absorbed. Simply increasing the calcium in the diet may not have much
effect unless calcium is in the right form, diet is balanced and the intestine is healthy
Vitamin D and bile salts are needed for efficient absorption. .
Iodine: this is needed only in small amounts, but it forms an essential part of the
molecule of thyroxin. Thyroxin is a hormone produced by the thyroid gland in the neck.
Special rich sources of iodine are sea fish, shell-fish and most vegetable ( if the soil
where they grow in not deficient in this mineral). In some parts of the world where soil
has little iodine, potassium iodine may be added to table salt to bring the iodine in the
diet to a satisfactory level.
Phosphorus: is needed for the calcium phosphate of bone and also for DNA. It is
present in nearly all food, but is particularly abundant in cheese, meat and fish.
Sodium: is consumed by the human body in form of sodium
chloride.(common salt). Sodium is a highly reactive, metallic and alkaline element. It is
very essential for life, as it is present in the extra-cellular fluids in the body. This essential
mineral is also found in bones and fluids around the cell. It is commonly found in saliva
2
and enzymes. It works along with potassium, which is another important cation present in
the intracellular fluids.
Sodium helps maintain the body water distribution and blood pressure. It also helps
maintain the acid-base balance. Sodium is also needed to stimulate muscle contraction as
it is the major component of nerves. Calcium and other minerals are kept in soluble form
due to sodium. It also stimulates adrenal glands and helps prevent heat strokes. Sodium
along with chloride and bicarbonate maintains the balance of electrically charged particles
in the fluids and tissues.
Sources of Sodium:
Sodium is found in the foods that we consume. The major source is the common table salt
that we use to season. . The other sources of food are soy sauce, pickles, olives and
sauerkraut. You even get salt from salty meats, fish, processed cheese, instant soups. In the
natural food groups, vegetables like dry lotus stems, leafy vegetables, pulses and legumes
are foods high in sodium. It is also present in shellfish, carrots, kidney and bacon.
Uses of Sodium




A low sodium diet that is combined with healthy weight loss diet helps reduce high
blood pressure.
It is used in the treatment of diarrhea, muscle cramps, dehydration and fever due
to its property of holding water in the body tissues.
Sodium helps in nerve transmission and muscle contraction that includes beating
of the heart.
It maintains a balance of positive and negative ions in the body fluid and tissues.
Hyponatremia is a medical term used for sodium deficiency. When the body's balance of
electrolytes becomes unstable, it means the person is suffering from sodium deficiency.
This situation arises if there is too much fluid in the body that leads to dilution of the
sodium or if the sodium levels are too low in the body. Excessive diarrhea or vomiting also
lead to sodium deficiency in the body.
Symptoms of Sodium Deficiency:
The symptoms of sodium deficiency include feelings of weakness, apathy, nausea and
cramps in the muscles of the extremities. Sodium deficiency, in very rare cases, may lead
to shock due to extremely low blood pressure. The other symptoms of sodium deficiency
are neurological, such as confusion, loss of reflexive movement, convulsions or even coma.
Treatment of Sodium Deficiency:
Sodium deficiency treatment includes intravenous saline, water restriction and
administration of diuretics. The person suffering from sodium deficiency is monitored, as
rapid stabilization may lead to heart failure. Sodium deficiency is commonly seen in
marathon runners or distance athletes. As they keep drinking water while running, their
body level of fluids increase leading to dilution of sodium. This condition is also called as
water intoxication. Thus, they are advised to drink sports drinks, sports gels or other
electrolyte replacement supplements.
Vitamins: vitamins are organic substances needed in very small amounts. They do not
have energy value at all. But without any of them several illnesses are caused. Examples
of vitamins are: Vitamin A, B, C, D, and K.
The features shared by all vitamins are:
 They are not digested or broken down for energy.
 Mostly they are not built into the body structure.
3
 They are essential in small quantities for health.
 They are needed in chemical reactions in the cells, working in association with
enzymes.
Plants can make vitamins in their leaves, but animals, have to obtain them from the diet.
If any of the vitamins is missing or deficient in the diet, a vitamin deficiency disease
may develop. Such diseases can be cured, at least in the early stages, simply by adding
the vitamin to the diet. Vitamins can be grouped as soluble in water or fat soluble.
These ones are mostly found in animal fats, or vegetable oils. Water soluble vitamins
are found in green leaves, fruits, and cereal grains. ((See table 10.1 on page 89))
Vitamins can be fat soluble as Vitamins A, D and K; or soluble in water as Vitamins
B,C and carotene, the precursor of vitamin A.
Vitamin
Why you need it
β Carotene
(precursor of
Vitamin A )
D
K
C
B (B1, B2,B3,B5,
B6,B7, B9,B12)
B12 (Folic Acid) is
recommended to
pregnant women, to
reduce the
incidence of birth
defects).
Disease related to
its lack
GOOD VISON
Night Blindness
It helps to make the
Keratomalacia
substance needed to
(cornea gets dry)
see in them light
Immune function
Low resistance to
deseases.
FOR BONES AND
RICKETS
TEETH
OSTEOPENIA
FORMATION
OSTEOPOROSIS
Blood clotting
PROBLEMS
process
WITH BLOOD
CLOTTING
To prevent flu and
colds; bleeding
gums, poor healing
of wounds.
Easily destroys
with cooking, so
it`s important to eat
fresh uncooked
food.
Provide cells with
energy
Foods rich in it
Liver, Fish, carrots
apple, and fresh
green leaves.
Milk, cheese,
yoghurt, liver and
cheese.
Green vegetables
(is also synthesized
by some bacteria of
the colon)
SCURVY
Citrus fruits.
Tomatoes
Beri beri (people
have little energy
and weak muscles)
Whole cereals
brown flour and
rice.
4
Dietary fibre: when we eat vegetables and other fresh plant material, we take in a large
quantity of plant cells. Cell wall of plant cells consist mostly of cellulose. Since we do
not have enzymes for digesting cellulose, plant cell walls reach the large intestine
without being digested. This undigested part of the diet is called fibre or roughage. The
colon contains many bacteria which can digest some of the substances in the plant cell
walls to form fatty acids. Fibre helps to prevent constipation and keep the colon healthy.
Most vegetable and whole (integral) cereal grains contain fibre, but white flour and
white bread do not contain much. Good sources of dietary fibre are vegetables, fruits
and wholemeal bread. (integral)
Water: is needed in much larger quantities (around 2-3 litres per day). Water is need for
several reasons:
 The cytoplasm in our cells is a solution of proteins and other substances in
water. All the metabolic reactions happening in our cells will only happen in
solution. Otherwise metabolism will stop and cells die.
 Water is used to transport substances around the body. Blood is mostly water, so
of a person becomes severely dehydrated, their blood gets thicker, and it travels
more slowly around the body.
 Water also helps in digestion; digested food, salts, and vitamins are carried
round the body as a watery solution in the blood.
 Excretory products such as excess salts and urea are removed from the body in
solution by the kidneys. Water dissolves waste products so that they can be
removed by urine.
 It evaporates from the skin when you are hot cooling you done.
 Water plays an essential part as a reactant and solvent.
 Since we lose water by evaporation, sweating, urinating and breathing we have
to take in water with the diet.
Different people need different diets: not everybody need the same amount of energy
in their diet. The more energy a person uses up each day, the more they need in their
diet. Different people also need different proportions of the different types of food. A
growing child will need plenty of protein for making new cells, an athlete needs proteins
for building muscles and plenty of carbohydrate for energy. A pregnant woman needs
extra iron, calcium and folic acid for the baby.
A good diet is called a Balanced Diet, and contains the right amount of energy to meet
a person’s needs. It also contains some of the seven types of food (carbohydrates, fats,
proteins, roughage, water, vitamins and minerals) it contains enough of each of them
but not excess of any of them. The right diet for a person may not be the right diet for
another person, even of your same gender or age (depends also on the lifestyle).
Fresh fruit and vegetables are a very important part of a balanced diet. They contain
many vitamins and minerals but they also contain roughage, or fibre. Fibre helps to
prevent constipation, helping to keep food moving quickly through the digestive system.
This reduces the risk of several different illnesses including bowel cancer. Brown rice
and whole wheat contain vitamins and roughage; so brown bread is much better for you
than white.
5
Practical Work Number
: To be done for ................................................
Answer the following questions:
1. Answer questions 2-5 from page 89
Read page 89 and answer:
2.Why is fibre important? Where can be mostly found?
3. State 5 reasons why water is necessary in the diet.
4.State which vitamin/s:
a) is responsible of blood clotting process. Which mineral also plays a role in it?
b) it`s lack can lead to blindness.
c) are soluble in water
d) is recommended to pregnant women.
5. Complete the following chart:
Vitamin
Why you need it
Carotene ( )
D
Blood clotting
process
Disease related to
its lack
Blindness
Foods rich in it
Milk, cheese,
yoghurt, liver and
cheese.
Green vegetables
To prevent flu and
colds; bleeding
gums, poor healing
of wounds.
6. What do you understand by balanced diet?
7. Caroline and Patricia are 23 years old. Patricia is pregnant and works in a
greenhouse. Caroline is a little overweight and works as a secretary in an important
cosmetic company.
Which advice would you give to both of them? What should each of them do and include
in their diet.
8. Find out the consequences of high cholesterol and make a short list with food rich in
it.
6
Homework : To be done for ............................................................
1. True or false: Justify ALL your answers.
(2 points)
1. Energy from the food is used to build complex molecules.
2. Our diet must contain proteins, carbohydrates and fats.
3. Fats, carbohydrates and fibre provide energy.
2. Select the correct option:
(1 point)
1. Lack of vitamin A:
a) Can lead to blindness
b) Can cause rickets
c) Can cause scurvy
2. The excess of carbohydrate is converted to:
a) Glycogen
b) Starch and glycogen
c) Fat or glycogen
d) Fat depots
3. State the main differences and similarities between carbohydrates and fats. (2 points)
4. Answer questions 1-5 of page 87.
(5 points)