Nutrition and Health (3) Flashcards
The seven main nutrients in food are:
- fat
- carbohydrates
- fibre
- protein
- water
- vitamins (C&D)
- minerals
The elements present in the main food groups are:
Carbs, fibre & fat = carbon, hydrogen, and oxygen
Protein = carbon, hydrogen, oxygen and nitrogen
What is a balanced diet?
All of the essential food groups in the correct proportion
What is an unbalanced diet?
This is a diet which contains too much of some of the essential nutrients and/or too little of others. This type of diet can lead to the body being damaged
What is a food test?
Food tests are carried out to identify what substances are present in foods. The food has to be put in a solution I.e. Dissolved in water, and then it can be tested for different food groups
Equipment needed for food tests
Safety goggles, wire gauze, heat proof mat, Bunsen burner, Tripod, Spatula, Pipette, Test tube rack, Boiling tubes, Beaker, Spotting tile, Pestle, Mortar And food samples
Describe the test for starch
Name of test - starch test
Method - add iodine solution (yellow-brown) to the food.
Positive result- it will turn from yellow/brown to blue/black
Describe the test for sugar
Name of test- Benedict’s test
Method - add Benedict’s solution (blue) to the food and heat in a water bath
Positive result - from blue to purple (lilac)
Describe the test for protein/amino acid
Name of test - Biuret test
Method - add sodium hydroxide to the food and then copper sulphate and shake
Positive result - it will turn from blue to green then orange then to a brick red precipitate depending on how much sugar is present
Describe the test for fat
Name of test - ethanol test
Method - mix the food with ethanol
Positive result - from clear to form a white emulsion
Describe the test for vitamin C
Name of test - DCPIP test
Method - add DCPIP (blue) to the food
Positive result - from blue to pink and then colourless
Explain the DCPIP test
Vitamin C or ascorbic acid, is a powerful reducing agent and a dye called DCPIP can be used to detect it. The vitamin C causes the dark blue colour to be decolourised to pink and eventually going colourless
Apparatus for the DCPIP test
Beaker, Syringe, DCPIP solution, Standard solution of ascorbic acid, Test tubes, Test tube rack, And fruit juice samples.
Examples of how are body uses energy and where it’s from
Your body uses energy all the time. We need energy for our heat to pump blood around the body, our brain to think and learn and our muscles to move. We get energy from the food we eat.
What are kilojoules and examples of them
Kilojoules are a measurement of energy. 1000 joules = 1 kilojoule (KJ) -1g of protein provides us with 17KJ - 1g of fat provides us with 38KJ - 1g of carbs provides us with 17KJ
How much energy do we need?
Approximately 70% of the energy you use up everyday keeps the body working. The other 30% is used for extra work and activities. The amount of energy that you need will vary at different times of your life.
Energy requirements of our body depend on three main factors:
Age - a teenager who is growing will require more energy than an elderly person
Gender - (male or female) generally men require more energy as they usually have more muscles and a larger body mass
Activity levels - an active person who does a lot of exercise will require more energy than someone sitting watching tv
What does BMI stand for
Body mass index
What is BMI & what is it used for
BMI is often used by health professionals to check if a patient is the right weight for their height
BMI = weight in kgs - divided by - (height in m)squared
What does BMR stand for & what is it?
Basal metabolic rate.
BMR is a measure of minimum- energy expenditure - how much energy is required to keep your body functioning when you are resting and relaxing in a (also known as your metabolism). It must be carried out long enough after a meal for digestion to be complete.
What will increase your BMR?
Anything that results in an increase to your metabolic rate. This includes exercise, stress, fear and illness
What is your BMR relative to?
Your body mass, age, weight and height. It is also affected by your gender; as it is widely regarded that men need more energy than women.
State three body functions that we need energy for as part of our BMR
- Breathing
- beating of the heart
- metabolism of cells
Suggest why our BMR tends to decrease as we get older
Less growth ie less metabolic activity
