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 Friday, August 28, 2015

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 NutrientHow the body uses itFood sources it is contained in CarbohydrateTo provide energyCereals; bread; pasta; potatoes (sugars and starch) ProteinFor growth, making new cells and repair of our bodies Fish; meat; eggs; dairy products FatTo provide energy, as a store of energy & for insulation Butter; oil; nuts MineralsNeeded in small amounts to maintain health Salt; milk (calcium); liver (iron) VitaminsNeeded in small amounts to maintain health Dairy foods; fruit; vegetables FibreTo provide roughage to help keep food passing through the gut Vegetables; bran; wholemeal bread WaterNeeded by cells and for body fluidsFruit 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

Experiment 1.Use the syringe to add 1cm 3 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 1cm 3 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?