Healthy Diet

D. Crowley, 2007

Healthy Diet

To understand what a healthy diet is, and how it can effect health if you are deficient in certain nutrients

Wednesday, April 19, 2023

Food Groups

What are the 7 food groups? Carbohydrates Fat Protein Vitamins Minerals Fibre Water

Essential?

Nutrients are found within different foods, and they all play important roles within the body

Nutrient How the body uses it Food sources it is contained in

Carbohydrate To provide energy Cereals; bread; pasta; potatoes (sugars and starch)

Protein For growth, making new cells and repair of our bodies

Fish; meat; eggs; dairy products

Fat To provide energy, as a store of energy & for insulation

Butter; oil; nuts

Minerals Needed in small amounts to maintain health

Salt; milk (calcium); liver (iron)

Vitamins Needed in small amounts to maintain health

Dairy foods; fruit; vegetables

Fibre To provide roughage to help keep food passing through the gut

Vegetables; bran; wholemeal bread

Water Needed by cells and for body fluids Fruit juice; milk; water(!)

Poor Diet

If you have too little of a particular nutrient, we say that you have a deficiency in that nutrient, e.g. fibre deficiency can lead to constipation

Mineral deficiencies - e.g. iron deficiency can lead to anaemia (too few red blood cells); iodine deficiency can lead to a swelling in the neck called a goitre

Vitamin deficiencies - e.g. vitamin A deficiency can cause blindness; vitamin C deficiency can cause scurvy (makes the gums bleed); and vitamin D deficiency can cause rickets (legs bow outwards in growing children)

Vitamins

Many deficiency diseases are caused by a lack of vitamins and minerals

In 1747 James Lind scientifically proved that eating fruits prevented scurvy: - He took 12 men suffering from scurvy He gave them different treatments He found those given fruits (such as lemons) were cured of

the disease

In 1795 the British Navy started giving lemons (or their juice) to sailors

Cooking Vitamin C

DCPIP is a blue chemical that turns colourless when added to vitamin C

How could you plan an experiment to find out if cooking vitamin C affects it?

You could add some drops of lemon juice to DCPIP and see if it changes colouring (recording how many drops you added)

You could then repeat this experiment, using cooked lemon juice. Again add and record the number of drops needed to turn the DCPIP colourless

Experiment1. Use the syringe to add 1cm3 of DCPIP to a test tube

2. Use the dropping pipette, add unheated lemon juice, one drop at a time until the blue colour disappears. Count and write down the number of drops you add

3. Fill a beaker ½ full with water and place on a tripod. Start heating (you need the water boiling)

4. Take a boiling tube and add lemon juice to about 2cm in depth. When the water in the beaker is boiling, place the boiling tube in it

5. Use the syringe to add 1cm3 of DCPIP to your second test tube

6. After 5 minutes, take the boiling tube out of the water and let it cool down for 10 minutes

7. Use the dropping pipette, remove some of the heated lemon juice. Add it one drop at a time until the blue colour disappears. Record the number of drops you have added

8. Place the boiling tube into the water again and boil for a further 5 minutes

9. Repeat steps 5 – 7 once more (if you have time)

Record your results, and explain your findings

You will need: -• 3 test tubes• 1 test tube rack• 1 beaker• 1 boiling tube• Stop clock

Findings

Hopefully you have found that orange juice contains vitamin C (turned the DCPIP colourless)

However, you may have noticed that cooking the vitamin C results in DCPIP either taking longer to become colourless, or not at all

What does this suggest to you?