Chapter Three - Nutrition and Health Flashcards
How are energy requirements calculated?
To determine how much energy a person needs, the Harris Benedict model calculates the Basal metsbolic rate (BMR) - the amount of energy required to maintain a constant body mass at rest. This takes into account your activity levels, size age and gender.
Why do we control our energy intake?
If a persons diet provides more energy than they use during normal day-to-day activities then they will store any excess as fat. Over time this can lead to obesity.
What is BMI? What is it used for?
Health professionals often use a persons body mass index (BMI) along with blood pressure readings to assess their general health. To calculate BMI divide the persons weight (kg) by the square of their height (m).
What is recommended to maintain a healthy body?
All diets should contain plenty of fresh fruit and veg and keep the amounts of salty, sugary and fatty foods to a minimum. This is reflected by government health initiatives such as the ‘5 a day’ campaign. Consuming a healthy diet individuals stand a better chance of avoiding conditions such as obesity, stroke, heart disease, diabetes, arthritis and high blood pressure.
Explain the need for the government to take action over current high levels of obesity
Higher levels of diet-related illnesses need more treatment and this is putting more pressure on the NHS and is costing the country more. May result in increased taxation
Give equation & How to calculate energy content in food
Energy released / Joules = mass of water / g X rise in temperature/degrees Celsius X 4.2
To obtain this data to use in equation, foods can be burned under a known mass of water. Temperature of the water can be recorded before and after to calculate temperature change.
Label diagram of measuring the energy content in food
- thermometer
- water
- mounted needle or forceps
- burning
Food test for sugar
Benedict’s test
Method - add equal volume of benedicts solution; heat carefully in a water bath
Positive result - colour change from blue to brick red ( green or orange indicates small amount of sugar)
Food test for starch
Starch test
Method - add iodine
Positive result - yellow/brown to blue/black
Food test for protein
Biuret test
Method - add sodium hydroxide followed by a few drops of copper sulphate; shake
Positive result - light blue to purple/lilac
Food test for fat
Ethanol test
Method - extract oil/fats in ethanol; add to an equal volume of cold water
Positive result - clear to forms white emulsion
Food test for vitamin C
DCPIP test
Method - add drops of the food juice to DCPIP
Positive result - blue to pink to colourless
What is a balanced diet
One that contributes the correct levels of each food group; carbs, proteins, fats, vitamins, minerals, water and fibre. If a diet contains too much or little of any the person will become malnourished.
Food groups, why each aspect is needed, good sources and deficiencies or problems;
Carbohydrates
Carbohydrates
- all are composed of carbon, hydrogen and oxygen
Glucose - provides energy rapidly, sweets & chocolate
Lactose - /\, milk (incl Breast)
Cellulose - indigestible a bulk of fibre comp of cellulose, all plant material (cell walls)
Starch - slow release energy, bread&rice&pasta&potato, comp of Chains of glucose
Glycogen - energy storage in animal cells, all animal material esp red meat, most animals store lots in muscles and liver
The amount of energy you need depends on;
- age
- gender
- level of activity
- in addition pregnant woman require more energy for development of their foetus
Food groups, why each aspect is needed, good sources and deficiencies or problems;
Proteins, fats and vitamins
Proteins - growth and repair, meat&fish&egg, comp of carbon, hydrogen and oxygen
Fats - energy&insulation, butter&fried food, comp of carbon, hydrogen and oxygen
Vitamin C - maintains cell health (esp in walls of blood vessels), citrus fruits, scurvy or gum deterioration and teeth lost
Vitamin D - strong bones&teeth, fish oils&eggs&milk&made by pigments in skin when exposed to sun, rickets - bones soften& can bow under weight
Food groups, why each aspect is needed, good sources and deficiencies or problems;
Minerals, water & fibre
Iron - part of haemoglobin molecule in red blood cells needed to transport blood, red meat&green veg, anemia
Calcium - strong bones&teeth, muscle contraction and clotting, milk, cheese & veg, osteoporosis (brittle bones) in later life
Water - all reaction take place in solution - transport, fluid in joints &cytoplasm, all drinks, fresh fruit&veg, dehydration, leads to loss of cell function
Fibre - prevents constipation&maintain healthy digestive system, whole meal bread, fresh fruit&veg,cereals, most fibre is cellulose in plant cell walls
