Learning objective
This presentation is the property of its rightful owner.
Sponsored Links
1 / 53

Learning Objective PowerPoint PPT Presentation


  • 92 Views
  • Uploaded on
  • Presentation posted in: General

Learning Objective. To understand the functions of Vitamins in the body. Starter – Fats and oils. Name two dairy products that are available in reduced fat versions . (2 ) Margarine/butter, milk, cheese. Describe visible and invisible fats, and give examples of each. (4)

Download Presentation

Learning Objective

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Learning objective

Learning Objective

To understand the functions of Vitamins in the body


Starter fats and oils

Starter – Fats and oils

Name two dairy products that are available in reduced fat

versions. (2)

Margarine/butter, milk, cheese.

Describe visible and invisible fats, and give examples of each. (4)

Visible fat is when the fat is visible to the eye (easy to detect)

e.g. fat on meat, cooking fats such as lard, oil, butter etc.

Invisible fats are part of food or when mixed with other

ingredients and difficult to detect. This includes products like

cakes, pastry and biscuits, also eggs yolks, nuts, seeds etc.


Starter fats and oils1

Starter – Fats and oils

What is the difference between fats and oils? (2)

Fats are solid at room temperature and oils are liquid at room

temperature.

Should we be eating more saturated or unsaturated fats in our

diet? Why? (2)

We should be eating more unsaturated fats. Saturated fats

come from animals sources and if eaten in excess can cause

many illnesses. Unsaturated fats come from plant sources.


Starter fats and oils2

Starter – Fats and oils

In detail, explain two dangers of eating a diet high in fats & oils(6)

Dangers of eating a diet high in fats and oils are people can

become overweight (obese), high levels of cholesterol, coronary

artery disease, heart disease etc.

In detail, explain two dangers of eating a diet low in fats & oils(6)

Dangers of eating too little fats and oils in the diet are low body

weight (anorexia/bulimia) dry, scaly skin, hair loss, cold

intolerance etc.


Vitamins

Vitamins

Vitamins are a group of different chemical

substances. Vitamins are identified by a letter

and also a name. The body requires only small

amounts of each vitamin. In general vitamins are

needed to regulate maintenance and growth of

the body.


Vitamins1

Vitamins

Vitamins can be classified according to the substances

in which they dissolve. There are two groups.

Fat-soluble vitamins

Vitamins A, D, E and K

Water-soluble vitamins

Vitamins C and the vitamin-B complex


Fat soluble vitamins vitamin a retinol

Fat soluble VitaminsVitamin A (Retinol)

Functions of vitamin A (Retinol)

  • To make a substance called visual purple, which is formed in the retina of the eye to enable it to see in dim light

  • Keep the mucous membranes in the throat and the digestive, bronchial, and excretory systems moist and free from infection

  • Maintenance and health of skin

  • Normal growth of children, particularly the bones and teeth.


Fat soluble vitamins vitamin a retinol1

Fat soluble VitaminsVitamin A (Retinol)

Functions of vitamin A (Retinol)

Animal sources

RETINOL

Plant sources

CAROTENE

Converted

Digestive system

RETINOL

absorbed

Stored in liver


Fat soluble vitamins vitamin a retinol2

Fat soluble VitaminsVitamin A (Retinol)

Sources of vitamin A (Retinol)

Vitamin A is found as retinol in animal foods:

  • Milk, cheese, egg (yolk), butter

  • Oily fish e.g. Herring, pilchard, sardine

  • Liver, kidney, cod & halibut-liver oil


Fat soluble vitamins vitamin a retinol3

Fat soluble VitaminsVitamin A (Retinol)

Sources of vitamin A (Retinol)

Vitamin A is found as carotene in plant foods:

  • Carrots, spinach, watercress, parsley, cabbage, prunes, apricots, tomatoes.


Fat soluble vitamins vitamin a retinol4

Fat soluble VitaminsVitamin A (Retinol)

Sources of vitamin A (Retinol)

Vitamin A is found as carotene in plant foods:

  • Carrots, spinach, watercress, parsley, cabbage, prunes, apricots, tomatoes.

    During digestion, carotene is converted into retinol. Two

    parts carotene are required to form one part of retinol.

    Vitamin A is added by law to margarine to ensure people

    obtain enough.


Fat soluble vitamins vitamin a retinol5

Fat soluble Vitamins Vitamin A (Retinol)

Special requirements

  • Children need plenty of Vitamin A for growth and development

  • Expectant and nursing mothers need extra vitamin A for development of the baby and the maintenance of the mother

  • People who cannot digest and absorb fat well may need to have a vitamin A injection to overcome this.


Fat soluble vitamins vitamin a retinol6

Fat soluble VitaminsVitamin A (Retinol)

Effects of Vitamin A (Retinol) deficiency

  • The retina does not make the substance visual purple and vision in dim light is impaired=night blindness

  • In severe cases the structure of the eye deteriorates and can lead to total blindness

  • The skin becomes dry and infected

  • Growth of children is effected

  • Pregnant women can develop a deficiency as the growing baby is provided with any vitamin A that is available in the diet


Fat soluble vitamins vitamin a retinol7

Fat soluble VitaminsVitamin A (Retinol)

Effects of Vitamin A (Retinol) excess

Too much vitamin A in the diet is poisonous to

the body as it is stored. This can affect the skin

and joints, especially in children.


Fat soluble vitamins vitamin a retinol8

Fat soluble VitaminsVitamin A (Retinol)

Effects of heat/cooking/destruction

Retinol and carotene are both insoluble in water,

and are unaffected by normal temperatures and

methods of food preparation.


Fat soluble vitamins vitamin d cholecalciferol

Fat soluble VitaminsVitamin D (Cholecalciferol)

Functions

  • Formation of bones and teeth

  • Helps the body absorb the minerals calcium and phosphorus


Fat soluble vitamins vitamin d cholecalciferol1

Fat soluble VitaminsVitamin D (Cholecalciferol)

Sources

Vitamin D is found in good supplies in the following foods:

  • Liver

  • Fish-live oils

  • Oily fish e.g. Herring, pilchard, sardine

    It is also found in smaller amounts in the following foods:

  • Egg yolk

  • Margarine (added by law)

  • Milk and dairy products

  • Sunlight is also an important source of vitamin D.

The amount of vitamin D in dairy food products are higher in the summer due to more exposure to the sun.

When the body is exposed to UV rays, a substance under the skin (dehydrocholesterol) is converted to cholecalciferol, which is sent for storage in the liver, to be used as required.


Fat soluble vitamins vitamin d cholecalciferol2

Fat soluble VitaminsVitamin D (Cholecalciferol)

Ultra Violet light

Animal sources

(Cholecalciferol)

Skin

Dehydrocholesterol

coverted to

Cholecalciferol

Digestive system

Cholecalciferol

Absorbed

Calcium

Phosphorus

Bones

Teeth


Fat soluble vitamins vitamin d cholecalciferol3

Fat soluble VitaminsVitamin D (Cholecalciferol)

Effects of deficiency

  • Absorption of calcium and phosphorus is reduced –reduces strength of teeth and bones

  • Rickets – legs become weak and bend (this mainly affects children)

  • Osteoporosis – weak and brittle bones

  • Growth of children can be affected


Fat soluble vitamins vitamin d cholecalciferol4

Fat soluble VitaminsVitamin D (Cholecalciferol)

Effects of excess

Too much vitamin D in the diet can be

dangerous as it results in an excess absorption

of calcium into the blood. The extra calcium is

deposited in the lungs and kidneys and can

cause death.


Fat soluble vitamins vitamin d cholecalciferol5

Fat soluble VitaminsVitamin D (Cholecalciferol)

Effects of heat/cooking/food preparation

Vitamin D is unaffected by normal cooking

temperatures and processes and does not

dissolve in water.


Questions

Questions

  • List the functions if vitamins A & D.

  • List the sources of retinol.

  • List the sources of carotene.

  • Why is milk produced in the summer richer in vitamins A & D than winter milk?

  • Why is margarine a good source of vitamins A & D?

  • How does ultra violet light help the body to make vitamin D?

  • Why is too much vitamin D dangerous?


Water soluble vitamins vitamin b complex

Water soluble vitaminsVitamin B complex

  • It is called vitamin-B complex due to at least 13 substances exist in this group of vitamins.

  • The main vitamins in the complex that we will be looking at are:

    • Thiamin (Vitamin B1)

    • Riboflavin (Vitamin B2)

    • Nicotinic acid

    • Cobalamin (Vitamin B12)


Water soluble vitamins vitamin b complex1

Water soluble vitaminsVitamin B complex

The main sources of vitamin-B complex are:

  • Cereals – especially wholegrain cereal products

  • Bread, flour, yeast and yeast extracts, beer, wheat germ

  • All meat – especially pork, ham, bacon, liver, kidney, heart

  • Eggs

  • Fish roe

  • Milk


Water soluble vitamins vitamin b complex2

Water soluble vitaminsVitamin B complex

Thiamin (Vitamin B1)

Functions

  • Involved in the metabolic reactions which release energy from carbohydrate

  • Required for the normal growth of children and the maintenance of general health

  • Required for the function and maintenance of the nerves


Water soluble vitamins vitamin b complex3

Water soluble vitaminsVitamin B complex

Thiamin (Vitamin B1)

Requirements

  • Thiamin cannot be stored in the body, so a daily supply is necessary for all age groups.

  • Requirements are increased during pregnancy and lactation, and also people who live a very active lifestyle.


Water soluble vitamins vitamin b complex4

Water soluble vitaminsVitamin B complex

Thiamin (Vitamin B1)

Deficiency

A deficiency of thiamin may occur for several reasons, including

alcoholism, some digestive disorders and pregnancy (loss of appetite,

vomiting)

A deficiency may result in the following symptoms:

  • Depression, irritability, difficulty in concentration, anxiety

  • Growth issues in children

  • Nerves become inflamed and painful

  • Severe deficiency leads to the disease beri-beri-this is when someone becomes so exhausted and loses weight, muscles become weak especially in the legs, ankles and wrists drop.


Water soluble vitamins vitamin b complex5

Water soluble vitaminsVitamin B complex

Thiamin (Vitamin B1)

Stability in food preparation

Thiamin is very soluble in water, and some is destroyed

by high temperatures used in cooking.


Water soluble vitamins vitamin b complex6

Water soluble vitaminsVitamin B complex

Riboflavin (Vitamin B2)

Functions

  • Essential for normal growth

  • Required for the release of energy from food, especially amino acids and fat.


Water soluble vitamins vitamin b complex7

Water soluble vitaminsVitamin B complex

Riboflavin (Vitamin B2)

Requirements

Riboflavin can be stored in small amounts in the liver,

spleen and kidneys, but a daily supply is required by all

ages.

Bacteria normally present in the intestine can produce

some riboflavin, but not enough to meet all the body’s

needs.


Water soluble vitamins vitamin b complex8

Water soluble vitaminsVitamin B complex

Riboflavin (Vitamin B2)

Deficiency

  • Failure to grow

  • Skin condition – dermatitis, and conjunctivitis (disorder of the outer membrane of the eye)

  • Tongue may swell, mouth and lips becomes sore.


Water soluble vitamins vitamin b complex9

Water soluble vitaminsVitamin B complex

Riboflavin (Vitamin B2)

Stability

Riboflavin is soluble in water, and is destroyed if heated

in the presence of an alkali e.g. Bicarbonate of soda.

Exposure to light also destroys the vitamin. This is why

foods such as milk should be stored in the dark.


Water soluble vitamins vitamin b complex10

Water soluble vitaminsVitamin B complex

Nicotinic acid (Vitamin B3)

Functions

Release of energy from food, especially carbohydrate

Requirements

A supply of nicotinic acid is required every day and

more is needed during pregnancy and lactation.


Water soluble vitamins vitamin b complex11

Water soluble vitaminsVitamin B complex

Nicotinic acid (Vitamin B3)

Deficiency

A deficiency can result in the disease pellagra, which is

characterised by the following symptoms:

  • Dermatitis

  • Dementia

  • Diarrhoea


Water soluble vitamins vitamin b complex12

Water soluble vitaminsVitamin B complex

Nicotinic acid (Vitamin B3)

Stability in food preparation

Nicotinic acid is readily soluble in water, but resistant to

heat, oxidation and alkali.

It is the most stable vitamin in the B complex, in normal

cooking processes.


Water soluble vitamins vitamin b complex13

Water soluble vitaminsVitamin B complex

Cobalamin (Vitamin B12)

Functions

It is required for the metabolism of amino-acids as well

as other enzyme systems throughout the body.


Water soluble vitamins vitamin b complex14

Water soluble vitaminsVitamin B complex

Cobalamin (Vitamin B12)

Requirements

  • Vitamin B12 is produced in the intestines by bacteria, and is only found in useful amounts in animal foods.

  • Vegans may have an insufficient intake.

  • More is needed when pregnant and during lactation.


Water soluble vitamins vitamin b complex15

Water soluble vitaminsVitamin B complex

Cobalamin (Vitamin B12)

Deficiency

It can lead to anaemia, in which the red blood cells

become enlarged.


Questions1

Questions

  • How many vitamins are there in the B complex?

  • Why do people who live a very active lifestyle require plenty of thiamin?

  • What are the symptoms of beri-beri and how is it caused?

  • What effects do cooking processes have on the B vitamins?


Water soluble vitamins vitamin c ascorbic acid

Water soluble vitaminsVitamin C (Ascorbic acid)

Functions

  • Required to make connective tissue which binds the body cells together

  • Assists the absorption of the mineral iron from the small intestine during digestion.

  • Assists in building of strong teeth and bones

  • Required for the production of blood and the walls of blood vessels

  • Required for the building and maintenance of the skin and linings of the digestive system.


Water soluble vitamins vitamin c ascorbic acid1

Water soluble vitaminsVitamin C (Ascorbic acid)

Sources

Vitamin C is found mainly in fresh fruits and vegetables.

Rich sources

Blackcurrants and green peppers

Good sources

Citrus fruits – oranges, grapefruits, lemons

Strawberries

Cabbage, spinach

Brussels sprouts, broccoli

Reasonable sources

Bean sprouts, peas

Potatoes

The amount of vitamin C present in food varies according to the time if year, stage and place of growth, variety of plant and degree of ripeness.


Water soluble vitamins vitamin c ascorbic acid2

Water soluble vitaminsVitamin C (Ascorbic acid)

Requirements

A daily amount of vitamin C is required to keep the

bodies store ‘topped up’ but it is not a vital

requirement every day. Ascorbic acid is stored in the

body, mainly in the liver and adrenal glands.

As a nation we eat potatoes in large quantities. These make a real contribution to our supplies of vitamin C.


Water soluble vitamins vitamin c ascorbic acid3

Water soluble vitaminsVitamin C (Ascorbic acid)

Deficiency

Prolonged deficiency may lead to:

  • Connective tissue not made or maintenance correctly

  • Walls of blood vessels weaken and break in places. Blood escapes and appears as small red spots (haemorrhages) under the skin.

  • General weakness, irritability, pain in muscles and joints.

  • Gums bleed, teeth loosen.


Water soluble vitamins vitamin c ascorbic acid4

Water soluble vitaminsVitamin C (Ascorbic acid)

Deficiency

A severe deficiency leads to a disease called scurvy.

Other deficiency symptoms include:

  • Cuts and wounds fail to heal properly

  • Scar tissue may weaken and break open

  • Anaemia because iron is not absorbed properly without vitamin c.

It is rare to see cases of scurvy in the UK but some elderly people on low income can show some symptoms –swollen gums and loose teeth.


Water soluble vitamins vitamin c ascorbic acid5

Water soluble vitaminsVitamin C (Ascorbic acid)

Stability in food preparation

Heat

50% of vitamin C is lost during cooking of green vegetables.

  • Avoid peeling vegetables such as potatoes before cooking

  • Cook as quickly as possible, with the lid on to reduce oxidation

  • Serve quickly

  • Over-cooking, reheating and keeping meals warm are all inadvisable


Water soluble vitamins vitamin c ascorbic acid6

Water soluble vitaminsVitamin C (Ascorbic acid)

Stability in food preparation

Oxidation

Once vegetables and fruit are harvested, the vitamin C content is

reduced through oxidation.

  • Fruits and vegetables should be stored in a cool, dark, dry, ventilated place as warmth speeds up oxidation.

  • Bad storage results in a 90% loss of vitamin C.


Water soluble vitamins vitamin c ascorbic acid7

Water soluble vitaminsVitamin C (Ascorbic acid)

Stability in food preparation

Water

Ascorbic acid is highly water-soluble.

  • Vegetables should not be soaked in water

  • Cook vegetables in very little water

  • Use up the cooking water for sauces/soups


Water soluble vitamins vitamin c ascorbic acid8

Water soluble vitaminsVitamin C (Ascorbic acid)

Stability in food preparation

Chopping

An oxidising enzyme (oxidase) which is present in the cell walls

of plants destroys vitamin C. If fruits and vegetables are

chopped, grated or bruised, the oxidase is activated.

  • Chopped foods such as coleslaw should be eaten soon after preparation

  • Oxidase is destroyed at 85oc, blanching vegetables before freezing them will conserve the ascorbic acid.


Questions2

Questions

  • What are the functions of vitamin C?

  • What is the connection between vitamin C and iron?

  • How is the amount of vitamin C present in food affected?

  • What is the effect of cooking processes on vitamin C?


Water soluble vitamins vitamin c ascorbic acid9

Water soluble vitaminsVitamin C (Ascorbic acid)

The effect of heat on Vitamin C experiment.

We will all use 50g white cabbage and look at how much vitamin C is lost through

a variety of cooking methods.

We will investigate:

  • Uncooked cabbage

  • Cabbage cooked for 2 minutes in 300ml water

  • Cabbage cooked for 4 minutes in 300ml water

  • Cabbage cooked for 6 minutes in 300ml water

  • Cabbage cooked for 8 minutes in 300ml water

  • Cabbage steamed for 2 minutes over 300ml water

  • Cabbage steamed for 4 minutes over 300ml water

  • Cabbage steamed for 6 minutes over 300ml water

  • Cabbage steamed for 8 minutes over 300ml water


Water soluble vitamins vitamin c ascorbic acid10

Water soluble vitaminsVitamin C (Ascorbic acid)

The effect of heat on Vitamin C experiment.

  • After each experiment drain the cabbage (YOU MUST KEEP THE WATER)

  • Put 5ml of indicator solution in a 15ml test tube

  • Then add 10 drops of the cabbage water

  • Hold up the test tubes against a white background. Line up the test tubes (make sure you know which experiment each is) from lightest to darkest purple

  • The lighter shade of purple solution, the higher the vitamin C content

  • The darker the shade of purple – the cabbage will have lost the least amount of vitamin C during the cooking process.


Homework

Date set – Wednesday 29th September

Due date – Wednesday 6th October

Homework

Produce an article and discuss the best methods

for cooking vegetables and explain why (e.g.

what method keeps the most vitamins)

This should be an informative, factual article to

ensure people are getting the most out of their

vegetables.


Food weekly

Food Weekly

This weeks hot topic is on:

How do you get the best of your greens?


  • Login