Amino acids Proteins are made from long chains of smaller molecules called amino acids. An essential amino acid is an amino acid that cannot be synthesized/made by the body, and thus must be supplied in its diet
HIGH BIOLOGICAL VALUE Contain all the essential amino acids Found in animal sources like meat, fish, eggs, cheese, milk and also plant source - soya beans which is a good source for vegans.
LOW BIOLOGICAL VALUE Contains only some of the essential amino acids Sources include Cereals, pulses and some nuts
DEFICIENCY The physical signs of protein deficiency include oedema, failure to thrive in infants and children, poor musculature, dull skin, and thin and fragile hair. Kwashiorkor deficiency disease causing growth failure, water retention, diarrhoea, apathy and often and often seen in developing countries
EXCESS PROTEIN Will contribute to energy intake and excess stored as fatty layer under the skin
EFFECT OF COOKING Protein denatures (changes) on heating, coagulates and sets Normal cooking will make protein more digestible- this is one of the main reasons we cook meat for example.
IMPACT ON HEALTH If intake is LOW, Growth may be retarded/ stunted Cuts and wounds may take longer to heal If intake is HIGH Excess can be used as a secondary source of energy and, if not required, will be converted and stored as fat therefore contributing to weight gain and obesity
FAT Fats are divided into the following categories Saturated fats Unsaturated fats Also be aware of Trans fatty acids
A diet rich in saturated fat tends to raise blood cholesterol particularly LDL (low density lipoprotein, the bad cholesterol) which could increase the risk of heart disease. SATURATED FATS Fats which are solid at room temp are mostly saturated fat Sources of saturated fat
UNSATURATED FATS Monounsaturated fats Polyunsaturated fats Essential fatty acids Trans fatty acids
Essential fatty acid Cannot be made in the body Omega 3 Omega 6
ESSENTIAL FATTY ACIDS OMEGA 3 Reduces the risk of a blood clot forming so reducing the risk of a heart attack Oily fish such as sardines, mackerel, herring Tuna fresh tuna but not canned
ESSENTIAL FATTY ACIDS OMEGA 6 Tend to decrease bad cholesterol, but too much may also decrease good cholesterol levels Polyunsaturated spreads eg. flora Corn and sunflower oils
TRANS FATTY ACIDS These are polyunsaturated fats artificially hardened by adding extra hydrogen They cause an increased risk of heart disease and rheumatoid arthritis and may be linked to some cancers Not listed on food ingredients but hydrogenated oils/ fats are listed Found in hard marg, biscuits, cakes, packaged snacks and any food label indicating hydrogenated fat
SOURCES OF FAT Margarine Butter Oils Cream Cheese Oily fish
FUNCTION OF FAT A concentrated form of energy Protects the vital organs Acts as an insulating layer under the skin(warmth) Assists absorption of fat soluble vitamins A,D,E,K
Remember fat can be classified as visible (fat you can see) and invisible fat (eg in cakes)
EFFECT OF HEAT Solid fat melts to liquid Fats are fairly stable at normal cooking temps and break into fatty acids and glycerol If oil continues to be heated a blue haze is given off and the fat ignites Smoking shows the chemical structure of the fat has broken down and the fat will go rancid
EFFECT ON HEALTH If intake is LOW The body will use stores of fat to provide energy resulting in weight loss If intake is HIGH The excess will be stored as a layer under the skin and will contribute to weight gain and obesity If the intake is of saturated fat there will be an increase in cholesterol therefore increasing the risk of CHD
CARBOHYDRATES To supply energy
Categories of carbohydrates Monosaccharide (sugars) Disaccharides (sugar) Polysaccharides (starches) OR Intrinsic those that form part of the cell structure Extrinsic not part of the cell structure eg sugar added to foods, honey, fruit juice
SOURCES OF CHO SUGARS Sugar Honey Soft drinks Cakes Biscuits Sweets STARCH Bread Rice Pasta Cereals Noodles Potatoes
EFFECT OF COOKING ON STARCH Dry heat Dextrinisation Moist heat Starch granules soften and swell, absorb liquid and thicken gelatinisation
EFFECT ON HEALTH If intake is LOW The person may feel tired as energy levels are low If intake is low over a long period of time, weight loss may occur as the body uses up stored energy (fat layers) If intake is HIGH it will be stored as fat in the body could lead to obesity
WHAT ABOUT SUGAR?
EFFECT OF COOKING ON Sugar melts SUGAR CARMELISATION DRY HEAT Caramelises (think toffee) Goes a brown colour This contributes to the colour of a baked item and forms a crust
EFFECT OF COOKING ON SUGAR MOIST HEAT When moist heat is applied, it dissolves At high temps and prolonged heating it becomes a syrup, which caramelises then chars when water evaporates
EFFECT ON HEALTH If the intake is LOW Energy levels may be low so individual will feel tired A reduced intake may help prevent dietary diseases like obesity, tooth decay and diabetes see next slide to explain these If intake is HIGH Excess will be converted and stored as fat so contribute to becoming overweight and obesity Bacteria feed on sugar in the mouth and produce an acid this can lead to tooth decay May contribute to type 2 diabetes as the body struggles to process the sugar
WHAT TO DO? Complete mind maps on PROTEIN FATS CARBOHYDRATES Complete crossword you started on Friday
FAT SOLUBLE VITAMINS Makes visual purple which helps to see in dim light Needed for normal growth and healthy skin One of the anti-oxidant vitamins Carotene is converted to Vitamin A in the small intestine VITAMIN A
FAT SOLUBLE VITAMINS VITAMIN D Required for the absorption of calcium Acts with calcium and phosphorus to give strong bones and teeth Available from sunlight Added by law to marg
DEFICIENCY OF VITAMIN D Rickets Osteomalacia
FAT SOLUBLE VITAMIN E Anti-oxidant which may help prevent cancers and heart disease Found in oils, egg yolk, oatmeal, dairy products and leafy green veg
FAT SOLUBLE VITAMIN K Needed for the normal clotting of blood
FAT SOLUBLE VITAMINS Effect of cooking Unaffected by cooking Not soluble in water
EFFECT ON HEALTH OF If intake is LOW The individual may suffer poor vision, particularly in dim light As it is an anti-oxidant the individual cold be at an increased risk of CHD and cancers Dry and infected skin and mucous membranes VITAMIN A If the intake is HIGH During pregnancy too much can be harmful to the developing foetus
EFFECT ON HEALTH OF VITAMIN D When intake is LOW Poor growth & a risk of rickets in children where bones become soft and bend Osteomalacia (adult rickets) in the elderly When intake is HIGH Can help ensure the absorption of calcium which is needed for strong bones and teeth very rare but can lead to deposits of calcium in the blood and heart A sufficient intake will help prevent rickets in children
WATER SOLUBLE VITAMINS
VITAMIN C WATER SOLUBLE Helps absorption of iron Anti-oxidant vitamin Helps cuts and wounds to heal
Effect of preparation on Vitamin C Avoid soaking as it is water soluble Prepare as needed as vit C lost through oxidation Use sharp knives to avoid damage to cells chop big Avoid peeling as most Vit C lies just under the skin Use acids to slow loss by oxidation (Lemon juice)
EFFECT OF HEAT & WATER ON VIT C Destroyed by fairly low temps so add to boiling water Cook for minimum time Vit C lost (leach) into cooking water so use as little as possible
DEFICIENCY OF VITAMIN C Scurvy very rare- Lips and tongue cracked, gums bleeding
EFFECT ON HEALTH If intake is LOW Cuts and wounds take longer to heal properly Anaemia may develop as Vit C required to absorb iron in the diet Greater risk of developing cancer and CHD If intake is HIGH Helps to prevent anaemia Helps to reduce risk of CHD and cancers Any excess will not be harmful as it is excreted from the body in urine
VITAMIN B1 (THIAMINE) WATER SOLUBLE Needed to release energy from CHO Needed for normal growth White flour fortified by law Fortified breakfast cereals Brown rice, wholemeal pasta
VITAMIN B2 (Riboflavin) To release energy from CHO, protein and fats Meat, liver Milk and eggs Green veg Wholemeal bread
VITAMIN B3 (Niacin) Needed for the release of energy Meat and meat products Wholemeal bread Pulses and nuts
VITAMIN B12 (Cobalamin) Helps to prevent pernicious anaemia Protects the nervous system All animal foods Fortified breakfast cereals
EFFECT OF COOKING ON VIT B COMPLEX Stable to temp up to boiling point Gradually destroyed with prolonged cooking
DEFICIENCY OF VITAMIN B Fatigue, depression Extreme deficiency is called beri-beri muscle wasting, enlarged heart
BENEFIT TO HEALTH If intake is LOW Tiredness due to energy not being released form food Depression and anxiety may occur Slow growth in children If intake is HIGH any excess will be removed from the body
FOLIC ACID/ FOLATE Helps prevent spina bifida Essential for the formation of red blood cells Green leafy veg Wholegrain cereals Fortified breakfast cereals
January 2016 Scotland considers adding folic acid to flour to help reduce the risk of neural defects like spina bifida
EFFECT ON HEALTH If intake is LOW Neural tube defects in unborn babies may develop A type of anaemia may occur called megaloblastic anaemia If intake is HIGH Unborn babies will grow and develop properly, avoiding spina bifida
CALCIUM & PHOSPHORUS Needed for strong bones and teeth
CALCIUM ABSORPTION Factors which assist absorption Vitamin D Lactose Protein the amino acids from protein combine with calcium to form salts which are readily absorbed Factors which hinder the aborption of calcium Lack of Vitamin D Phytic acid (found in wholegrain cereals) NSP Fats saturated fatty acids form insoluble soaps with calcium Oxalic acid found in rhubarb and spinach
EFFECT ON HEALTH If intake is LOW A shortage may lead to poor bone formation osteomalacia/osteoporosis AS calcium is needed for correct functioning of muscles/ nerves so, with an active lifestyle, could give muscle cramps If intake is HIGH As calcium combines with phosphorus to give bones and teeth their hardness there is a reduced risk of osteoporosis/ osteomalacia Good bone density
IRON A component of haemoglobin needed to transport oxygen around the body Sources Red meat Fortified flour and bread Green leafy veg Cocoa, plain chocolate
ANAEMIA SPECIAL REQUIREMENTS Babies born with a supply to last up to 4 months as milk contains little iron Pregnant women to allow for the development of the baby Girls and women loss of blood due to the menstrual cycle must be replaced
Reasons why iron may be lacking in the diet
Snacking and grazing throughout the day rather than traditional meals could reduce iron intake. Less red meat may be eaten for health, moral or religious reasons.
If people are not aware of nutrition or are lacking in the skills to prepare iron-rich foods then sufficient iron may not be included in their diet.
Dark-green vegetables can be unpopular, particularly with younger age groups. If a good supply of fruit and vegetables, supplying vitamin C, is not eaten, then absorption of iron will be affected.
EFFECT ON HEALTH If intake is LOW Increased risk of tiredness and anaemia as haemoglobin is lacking in the blood If intake is HIGH May help to prevent anaemia If intake is particularly high over a period of time it can collect in the liver and be toxic
SODIUM Needed to maintain correct fluid balance of the body Required for correct muscle and nerve activity low intake can result in muscle cramps Sources Table salt Bacon Cheese Savoury snacks Canned foods
EFFECT ON HEALTH If intake is LOW People are rarely deficient in sodium but muscle cramps may occur, especially after exercise If intake is HIGH A high intake over a period of time will contribute to high blood pressure, strokes and coronary heart disease
PHOSPHORUS Works with calcium in the formation, development and maintenance of bones and teeth Found in milk, cheese, yogurt Bread and cereal products Meat and meat products Fish Nuts
EFFECT ON HEALTH People are rarely deficient in phosphorous, but insufficient amounts could affect the body s ability to build and maintain healthy bones
WATER Requires for all body fluids Helps regulate body temp Fruit and veg Tap water Milk Lubricates joints and membranes
EFFECT ON HEALTH If intake is LOW The person may become dehydrated, which results in confusion and lack of concentration If intake is HIGH It will help flush out toxins from the body
NSP Non Starch Polysaccharide Aids removal of waste Helps prevent constipation, bowel disorders, bowel cancer 2 types soluble and insoluble NSP see p18 of notes Found in wholemeal bread, wholegrain cereals, fruit and veg, pulses
EFFECT ON HEALTH If the intake is LOW The individual is more at risk of bowel disorders like constipation and bowel cancer If the intake is HIGH Your body will adapt to this amount of fibre and help prevent constipation and bowel disorders Helps to give a feeling of fullness so helps prevent over-eating May help lower LDL cholesterol and so reduce risk of CHD
INTER-RELATIONSHIP OF NUTRIENTS Calcium, phosphorus and vit D Iron, Vit C and folic acid Vitamin B and CHO Iron, NSP and Phytic acid ACE vitamins
IRON, VITAMIN C AND FOLIC ACID About only 10% of iron which is eaten is actually absorbed Iron in our food is ferric iron and cannot be absorbed until it is changed to ferrous iron Vit C needed to change ferric iron to ferrous iron Folic acid improves red blood cell count if iron is lacking then folic acid can supplement the supply
CALCIUM, PHOSPHORUS, VITAMIN D Absorption of calcium controlled by Vitamin D Calcium and phosphorus make calcium phosphate which gives teeth their hardness
Factors which can affect absorption of iron a type of acid found in wholegrain cereals called phytic acid
Factors which can hinder absorption of calcium 1.phytic acid found in wholegrain cereals 2.saturted fats 3.oxalic acid
VITAMIN B AND CHO Vit B acts as a link in a complex chain of chemical reactions which release energy from CHO Vit B1 releases energy from glucose, Vit B2 & 3 release energy from food
IRON, NSP AND PHYTIC ACID Phytic acid found in wholegrain cereals These prevent the absorption of iron from foods Phytates found in food containing NSP will remove iron from the body in waste materials May result in anaemia
BENEFIT TO HEALTH OF ANTI-OXIDANT VITAMINS A,C,E Ward off free radicals which are a result of natural processes in the body eg. breathing, digestion and this helps prevent damage to the cells therefore reducing the risk of cancers and heart disease
- Vitamin E improves the activity of Vitamin A in the body. - When vitamin E has been used by the body and is finished, Vitamin C works on Vitamin E to recycle it.
Task 1 Make a table on the impact of nutrients on health which will be useful when answering the nutritional analysis question in the exam paper
Technique FOC This could be positive or negative Answers must link to the nutrients found in food Evaluate the nutritional suitability of oily fish in the diet.(4) Think about salmon, mackerel, herring etc 4 marks means 4 points to be made
Exam style questions Evaluate the nutritional suitability of oily fish in the diet.(4)
Evaluate the contribution made by fruit and vegetables in the diet of a nursery child.(4) Evaluate ready meals in the diet of man suffering from heart disease.(4)
There will be a compulsory question like this in the exam and the internal assessment