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Healthy Diet

Healthy Diet

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Healthy Diet

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  1. Healthy Diet D. Crowley, 2007

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

  3. Food Groups • What are the 7 food groups? • Carbohydrates • Fat • Protein • Vitamins • Minerals • Fibre • Water

  4. Essential? • Nutrients are found within different foods, and they all play important roles within the body

  5. 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)

  6. 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

  7. 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

  8. You will need: - • 3 test tubes • 1 test tube rack • 1 beaker • 1 boiling tube • Stop clock Experiment • Use the syringe to add 1cm3 of DCPIP to a test tube • 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 • Fill a beaker ½ full with water and place on a tripod. Start heating (you need the water boiling) • 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 • Use the syringe to add 1cm3 of DCPIP to your second test tube • After 5 minutes, take the boiling tube out of the water and let it cool down for 10 minutes • 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 • Place the boiling tube into the water again and boil for a further 5 minutes • Repeat steps 5 – 7 once more (if you have time) Record your results, and explain your findings

  9. 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?