Transcript Slide 1
3.1 Nutrients – Functions and sources 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 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 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 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 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 Fats • Main function: Provide energy, provide insulation, supply fatsoluble 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 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 Minerals • Minerals are micronutrients, two important minerals are calcium and iron Calcium • Main functions: – 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 Iron • Main functions: – 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 Vitamins • Vitamins are also micronutrients, they include: – Vitamin A – Vitamin D – Vitamin C – B-group vitamins such as thiamin, riboflavin, niacin and vitamin B12 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 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 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 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 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 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 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 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