1. 3.1 Nutrients – Functions and sources

2. Nutrition for youth health
One of the key behavioural determinants that affects the health and development of Australia’s youth is food intake
Nutrition is the process of eating to nourish our bodies. It is also the scientific study of why we eat

3. Nutrients
To understand how food affects health and development of youth, it is important to look at nutrients, how they work (function) and the foods they are found in (sources)
Nutrients are the chemical components of food; they are required by living thing to maintain life
There are many different types of nutrients

4. Types of nutrients
The many different types of nutrients can be classified into two main forms:
Macronutrients: Needed by the body in large quantities – proteins, carbohydrates, fats and water
Micronutrients: Needed by the body in relatively small amounts – vitamins and minerals

5. Protein Main function: build, grow and repair cells
Made up of smaller units called amino acids
Classified as either complete or incomplete depending on composition of amino acids
Food sources include:
Complete: meat, chicken, cheese, eggs, milk
Incomplete: rice, legumes, nuts, vegetables

6. Carbohydrate Main function: provide energy or fuel
Classified as monosaccharides, disaccharides or polysaccharides
Food sources include:
Monosaccharides: glucose and fructose found in honey and nuts
Disaccharides: sucrose and lactose found in sugar and milk
Polysaccharides: Starch found in rice and pasta and cellulose found in wholegrain breads and cereals

7. Fats
Main function: Provide energy, provide insulation, supply fat-soluble vitamins and essential fatty acids
Classified as: saturated, trans, monounsaturated and polyunsaturated
Food sources include
Saturated: meat, butter, cream, coconut cream
Trans: hydrogenated vegetable fats, manufactured margarines, cakes and biscuits (also found naturally in smaller quantities in meat and dairy)
Monounsaturated: olives, olive oil, avocado, nuts
Polyunsaturated: some margarines, vegetable oils, oily fish such as salmon, tuna and sardines

8. Water Most important nutrient of all
Essential for bodily functions, including: digestion, absorption, circulation, regulation of temperature, lubrication, transportation of nutrients, oxygen and wastes
Sources: fresh water, fruit and vegetables

9. Minerals
Minerals are micronutrients, two important minerals are calcium and iron

10. Calcium Main functions: Main sources:
forms hard structure of bones and teeth; regulates contraction and relaxation of muscles; assists in blood clotting; transmits nerve impulses
Main sources:
Milk and milk products, green leafy vegetables, tofu and soy bean products, fish with edible bones such as tinned tuna, nuts and seeds

11. Iron Main functions: Sources:
Essential component of haemoglobin – the pigment that gives blood its red colour
Formation of red blood cells
Sources:
Red meat, chicken, seafood
Wholegrain breads and cereals, legumes, dark green leafy vegetables

12. Vitamins Vitamins are also micronutrients, they include: Vitamin A
Vitamin D
Vitamin C
B-group vitamins such as thiamin, riboflavin, niacin and vitamin B12

13. Vitamin A Functions Food sources Healthy vision Healthy skin
Resistance to infection
Maintaining the mucous membranes that line the respiratory, gastrointestinal and urinary tracts as well as the mouth nose and ears
Normal growth of children, particularly teeth and bones
Animal sources such as liver, oily fish, full-cream milk, egg yolk and cheese
orange and green fruit and vegetables such as carrots, spinach, broccoli, pumpkin, mango and apricots

14. Vitamin B Functions Food sources
absorption and metabolism of calcium and phosphorous to assist the formation of bones and teeth
cell growth and development
healthy functioning of the nervous system and the immune systems
Fish, especially fish with a high fat content, such as sardines and salmon
meat, eggs and dairy products, including butter
fortified foods, such as margarine

15. Vitamin C Functions Food sources
formation of collagen, the connective tissue in skin, ligaments and bones
promoting the healing of wounds
absorption of iron / formation of red blood cells
preventing haemorrhaging and bleeding gums
fighting infection by maintaining white blood cells, which act as bacteria fighters
the production of thyroxin, a hormone involved in metabolism
Fruit and vegetables such as: blackcurants, oranges, mangoes, pineapples, grapefruit, kiwi fruit, raspberries, capsicums, potatoes, broccoli and spinach

16. Thiamin (vitamin B1) Functions Food sources
Normal functioning of nerve cells
Muscle tone
fortified breakfast cereals
yeast extracts (vegemite and marmite)
liver
kidney
lean pork
wholemeal bread
sesame seeds

17. Riboflavin (vitamin B2)
Functions
Food sources
Healthy skin and eyesight
Involved in the production of red blood cells
yeast extracts (vegemite and marmite)
liver
lean red meat
chicken
fish
milk and milk products
eggs
wholegrain breads and cereals

18. Niacin (vitamin B3) Functions Food sources blood circulation
reducing cholesterol levels in the blood
important for maintaining healthy digestive tract
yeast extracts (vegemite and marmite)
wholegrain breads and cereals
fortified breakfast cereals
liver
fish
eggs

19. Pyridoxine (vitamin B6)
Functions
Food sources
metabolism of protein
production of red blood cells
development of the nervous system
liver
lean red meat
fish
chicken
wholegrain breads and cereals

20. Cyano-cobalamin (vitamin B12)
Functions
Food sources
formation of red blood cells
formation of nerve cells and DNA genetic material
metabolism of carbohydrates and fats
liver
kidney
meat
oysters
fish
seafood
eggs
milk