Food + Nutrition

Nutrition- one of the characteristics of all living things, cells in body are made of biomolocules that provide the necessary building blocks for growth, repair and energy. Humans get biomolocules from their diet.

A balanced diet provides people with biomolcules, minerals and water

Food types

Carbohydrates

• Starch- slow supply of energy - found in potatoes, bread, pasta and rice

• sugar- fast supply of energy - found in fruit and sweets

• Fibre- prevents constipation - found in whole weat bread, fruit, vegtables and cereals

Protein

• Growth and repair of cells and makes muscle, hair and enzymes - found in lean meat, fish pulses and dairy

Fats

• provide a store of energy and insulate and protect internal organs - found in meat, dairy and chocolate

vitamins

• Vitamin c - healthy teeth, gums, joints and immune system - found in fresh fruit and vegtables

• vitamin d - strong bones - found in dairy

minerals

• iron - builds biomolocules, eg. haemoglobin in red blood cells - found in meat and fresh fruit and vegtables

• Calcium- assists chemical reaction in cells - found in dairy

Water

• acts as a solvent, transports materials in blood, removes waste, regulates tempature- found in water, liquids, fruit and vegtables

food pyramid

1. Vitamins and minerals (fruit and veg)- 5-7 portions per day

2. Carbohydrates (bread, potatoes, pasta rice) - 3-5 portions per day

3. Calcium (dairy) - 3 portions per day

4. Protein (meat, fish, pulses) - 2 portionsper day

5. Fats (oils and butter) - small amounts daily

6. High in sugar and salt - not every day

Factors that affect diet

• Age - young people are still growing need to eat more

• Sex- males need more than females

• Genetics - physically larger and taller people need more

• Health- when people are ill they may loose their apetite

• Physical activity- people who are more physically active need to eat more than those that are less active

Energy from food

The unit for energy is joules (J). Food is measured in thousands of joules, kilojoules (KJ).

If a person consumes more energy than needed it is stored as fat. Excess fat can leed to high blood pressure which can lead to a higher chance of a stroke or heart disease.

Experiments to test if certain substances are present

To test for starch

chemical used: Iodine

Colour if present: black/blue

How to test: place a food sample in tray, pour on a drop of iodine

To test for protein

chemical used - biuret reagent

colour if present: purple

how to test: place food sample in tray, pour on a drop of biuret reagent

to test for fat

material used to sample: brown paper

state if present: translucent

how to test: place a sample of each food on paper, hold up to window