NutrientsCarbohydrates Water Fats Minerals Proteins Vitamins
Composition of Carbohydrates Come from plant foods Cheapest and most plentiful of all nutrients Foods which contain carbohydrates, are called energy foods All of the energy obtained from food starts with a single sugar unit - glucose. Some plants store energy for later use by combining sugars to make starch.
Classification of Carbohydrates Sugar Starch Cellulose Pectin
Carbohydrates - SugarSugars are found inhoney, fruit (bothfresh and dried) softdrinks, milk andsugar.
Carbohydrates – Cellulose / FibreCellulose or Dietary Fibre is foundin whole cereals wholemeal bread outer skins of fruit and vegetables brown rice Oatmeal In refined foods the dietary fibre isremoved during processing e.g.wholemeal flour contains fibre butwhite flour does not.
Carbohydrates - PectinPectin is found inripe fruit
Functions of CarbohydratesCarbohydrates provides the body withheat and energyFibre helps the movement of food throughthe intestine.Fibre rich and starchy foods provide a "fullfeeling“Pectin helps jam to set
RDANutritionists believe that the amount ofsugar eaten in the western countriesneeds to be decreased and the amount offibre needs to be increased.The Recommended Dietary Allowance(RDA) of fibre is now 30g per day. We inthe western world eat about half therecommended amount-15g per day.
FatsFat is an importantnutrient because itgives us energyThe body storesenergy as a layer offat under the skin.This is called adiposetissue
Composition of FatsFats are made fromglycerol and fatty acidsEach glycerol is attachedto three fatty acidsGlycerol and fatty acidscontain the elementscarbon, hydrogen, andoxygenFats contain a lot ofcarbon. This is why theygive us so much energy.1 gram of fat gives us 9kilocalories
Classification of FatsFats are classified into two groups: Saturated Fats come mainly from an animal source such as meat, eggs, milk and dairy produce e.g. cream and butter. There is a lot of saturated fat in butter and lard Unsaturated Fats come mainly from plant and fish sources such as peas, beans and lentils, whole cereals, nuts, cooking oil, polyunsaturated margarine and oily fish
Functions of Fats Fat insulates the body. A layer of fatunder the skin prevents heat loss from thebody. Fat protects the delicate organs such asthe kidneys and nerves. A layer of fatsurrounds them. Fats provide the body with heat andenergy. This helps to keep the body at thecorrect temperature (37o C). Fat is a source of the fat-soluble vitamins
RDA of FatsIt is recommended that we eat 50%saturated fat and 50% unsaturated fat inour dietPeople in the western world eat too muchsaturated fat and it is recommended thatwe cut down on our intakeWe should also increase our intake ofunsaturated fats
To cut down on Saturated Fats Grill rather than fry. Use vegetable oil instead of hard fats forfrying. Remove visible fat from meat. Look for hidden fats in the diet e.g. pastriesand crisps. Use low fat milk, cheese, yoghurt andmayonnaise
ProteinOur bodies are made up of billions of cells,which contain proteinThroughout our lives cells wear out andare replacedAll the material for new cells comes fromfoodThe main nutrient involved in the buildingof new cells and replacing of worn cells isprotein
Composition of ProteinsProteins are made up of small units calledamino acidsThe amino acids, which the body cannotmake, are known as essential amino acidsAdults need 8 and children need 10essential amino acids.
Composition of ProteinsProteins are broken downinto amino acids in thedigestive systemAmino acids are smallestunits of Protein. They canthen be used to build updifferent proteins for theformation of new cells inthe bodyAmino acids are made upof the elements carbon,hydrogen, oxygen andnitrogen
Classification of ProteinsClassified into two groups:HBV and LBVHigh Biological Value Proteinscome mainly from animalfoods such as meat, fish,eggs, cheese and milkLow Biological Value Proteinscome mainly from plant foodssuch as peas, beans andlentils, whole cereals and nuts.These foods also contain fibreand are low in fat
Functions of ProteinsThe functions of proteins are: Growth of new cells such as skin hair and blood. Repair of damaged cells. Production of heat and energy. Manufacture of important body chemicals such as enzymes, hormones and antibodies.
RDA of ProteinsThe RDA of proteindepends on yourbody weightFor every kilogram ofbody weight one gramof protein per day isneeded, e.g. if youweigh 60 kg you need60 g of protein perday
VitaminsThe word "vitamin" comes from vita, theLatin for "life“Everybody must eat a certain amount ofvitamins to stay healthyVitamins are chemicals found in very smallamounts in many different foods. Tinyquantities are enough for the needs of thebodyIf people live on a very limited range offoods they may not get their proper shareof vitamins
Classification of VitaminsVitamins, of which thereare 14, are classifiedinto two main groups:Water soluble and FatsolubleFat soluble – stored inbodies fat tissue A, D, E & KWater soluble – notstored in the body B vitamins, folic acid & vitamin C
VitaminsFat soluble: Vitamin A - needed for healthy vision, bone growth, reproduction and the immune system found in dark green, orange and yellow vegetables, such as spinach, carrots, broccoli, mangos, apricots, vegetable soup and tomato juice. It is also found in meat and dairy products such as liver, beef, chicken, whole milk and eggs.
VitaminsFat soluble: Vitamin D - controls the absorption of calcium and phosphorus, which are essential for bone growth and development sardines and tuna, liver, egg yolks, some breakfast cereals and vitamin D-fortified milk. Vitamin D can also be made when the skin is exposed to sunlight
VitaminsWater soluble: Vitamin C - helps to maintain skin integrity, absorb iron from the gut and heal wounds, and is important in immune functions Vitamin C is found in citrus fruit and juices, tomatoes, spinach, potatoes, berries, green and red peppers, and broccoli
VitaminsWater soluble: Folate (folic acid), also called vitamin B9 is essential for the normal formation of the red blood cells, protein metabolism, growth and cell division Food sources include liver, citrus juices and fruits, beans, nuts, seeds, liver, dark green leafy vegetables.
MineralsThe human body requires about 20 mineralelementsEach has a specific function and is found incertain foodsA good varied diet should supply all essentialmineralsSome minerals are described as traceelements because the are required in smalleramountsMinerals are lost into the water during cooking
MacromineralsCalcium - for muscle and digestive system health,builds bone, neutralizes acidity, clears toxins, helpsblood stream Found in milk, cheese, green leafy vegetablesPotassium – for growth of lean tissue Found in bananasSodium – regulation of water balance in the blood Found in table salt, bacon, snack foodsSulfurMagnesiumPhosphorus
Trace MineralsIodine – Needed for the formation ofthyroxine, a hormone in the thyroid gland whichcontrols metabolism Found in vegetables and sea fishIron – Needed to make red blood cells Found in red meat, liver & cabbageManganese – Processing of oxygenZincCobaltCopper
WaterWater is absolutelyessential to life. Over70% of the human bodyis made up of water. It isfound in: Muscles Saliva Blood Digestive Juices Mucus Sweat
Composition of WaterWater contains the elements hydrogenand oxygenThey are present in the ratio 2:1, two partshydrogen to one part oxygenPure water freezes at 0C and boils at100C
Sources of WaterThe main sources of waterare drinking water andbeverages like tea, coffeeand alcoholic drinksWater is also present inmany other foods like meatand fishFruits and green vegetablesare high in water. Almost allfoods contain water, exceptthose with a high fat content(butter), and dry foods(sugar and flour)
Functions of WaterIt is the chief component of all body fluids.It helps dissolve foods and aids digestion.It helps remove waste material from the body.It regulates body temperature by perspiration.It is a source of dissolved minerals such asflourine and calcium.It keeps the body fluids liquid so that they mayflow easily.
RDA of WaterAs 2-2.5 litres of waterare lost daily byexcretion, andperspiration, an equalamount is required dailyby the body to avoiddehydration1.5 litres of water isobtained from beveragesand 0.8 from food.