Food & NutrientsFood & Nutrients

Why do we need food?Why do we need food?

Food eatenBurnt up in respiration

to produce energyStorage

Growth of new tissue

Repair of damaged

tissue

Movement (Kinetic energy)

Warmth

(heat energy)

The 5 Nutrient groups & 5 Food groups

►1. Carbohydrates►2. Lipids (fats and oils)►3. Proteins►4. Vitamins►5. Minerals

1. Carbohydrates

►Chemical compounds of carbon, hydrogen and oxygen (CH2O)

►Easiest source of fuel for the body to utilise

►Comes from plants in the form of sugars and starches

►Starch – from vegetables►Sugars (glucose)– mainly from fruits

1. Simple carbohydrates

►One or two units of sugar linked One or two units of sugar linked together to form a chaintogether to form a chain

► Includes sugars such as glucose and Includes sugars such as glucose and sucrosesucrose

► Tastes sweetTastes sweet

1. Complex carbohydrates

►Hundreds or thousands of sugar units linked to single molecules

►Two groups – high fibre and low fibre

►High fibre we can’t digest because cellulose is indigestible

►Cows have the necessary enzyme to break it down which is why they can eat grass

1. Carbohydrates•Complex carbohydrates can be broken down by the enzyme amylase to simple carbohydrates. Amylase is in our saliva.

Amylase

Long chain complex carbohydrate

Many short chain simples carbohydrates

2. Lipids – fats & oilsFats are solid at room

temperature &

come from animal tissue

•Lipids are vital to all animals

•Part of cell membranes

•Important in nerve tissue

•Provide a high amount of energy

Oils are liquid at

room temperature& come from

plants

2. Fat molecules

Lipase

Glycerol

Fatty Acids

•Fat molecules are made up of fatty acids and glycerol

•The enzyme used to break them down is called lipase

•We need to break them down so our bodies can use them

•Lipase is released in the small intestine

3. Protein►Most foods contain some protein,

especially food from animals►Main structural part of body cells

(needed for growth and repair)►Make up the main chemicals that control

the body

3. Proteins

► Made up of lots of amino acids► 20 different amino acids in total► Amino acids contain carbon,

hydrogen, oxygen and nitrogen► About half can be made by our

bodies alone► 8 Essential amino acids must

come from our diet

Pepsin

Pepsin

3. Protein deficiency

Kwashiorkor

4. Vitamins

►Only need in small amounts (compared to Carbohydrates, Proteins and fats)

►Some made by body (K & D)►Most need from diet►A lack of any one results in deficiencies► Vitamin A, B1, B2, B3, B6, B12, C, D, E, K► Most are water soluble so therefore our

body cannot store them► Some are fat soluble and are therefore

stored in our fat

4. Vitamin deficiencies

Scurvy – Lack of Vitamin C

4. Vitamin deficiencies

Rickets – Lack of Vitamin D

5. Minerals

►Needed for growth & general health►Calcium, fluorine, iron, iodine, phosphorus,

sodium, potassium, zinc►Many herbivores (eat vegetables only)

can’t get enough sodium and chloride from their diet so they will visit natural salt licks – and lick the ground to get enough!

The End !The End !