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Carbohydrates Proteins Fats Minerals Vitamins Water Fibre (Roughage) C = carbo Basic formula (CH20)n H20 = hydrate All Carbohydrates are converted to glucose and absorbed into the blood n = 6 C6 H12 O6 Glucose – vital fuel: CHO have a reciprocal relationship with fat ↑ CHO → ↓ Fat Chemically carbohydrates are defined by their number of saccharide units in their structure Monosaccharides Disaccharides Oligosaccharides Polysaccharides Originate from plants – CO2 + H2O – Photosynthesis Not all carbohydrates are digestible 1 gram of carbohydrate = 4kcal In our diet, starches and sugars are main sources of dietary carbohydrate Function of Carbohydrate – supply energy, protein sparing, prevents ketosis – breakdown fatty acids Intrinsic sugars: sugars which are incorporated within intact plant cell walls; eg. fruit and vegetables Extrinsic sugars: refined sugars; eg. Fruit juices, honey and milk Non-milk extrinsic sugars: sugars are present in a free and readily absorbable state eg. sucrose Total carbohydrate intake should provide up to 50% energy Non-milk extrinsic sugars should not exceed 11% energy intake Starches, intrinsic and milk sugars should contribute to 39% energy intake Certain diets promote restricted intake of carbohydrates Atkins Diet – low carbohydrate diet GI Diet – Encourages foods with low glycaemic index (GI) <60 Contains carbon, hydrogen, oxygen and nitrogen Protein regulates and maintains body functions; structural (skeleton, connective tissues), protective (tears, mucus), transport (plasma proteins and hormones) and enzymatic (protein synthesis) Protein are made up of 20 different amino acids bonded together in different sequences to form may SPECIFIC proteins Twenty amino acids are important in nutrition All amino acids have an acid group and an amino group attached to a carbon atom The rest of the amino acid is represented by R and is different for every amino acid The carbon to which the carboxyl is attached is the alphacarbon Amino acids have 4 different groups around the alpha carbon resulting in optically active L or D isomers or enantiomers Essential (indispensable) Amino Acid - One that the body is unable to make or can only make in inadequate quantities - Need to be consumed from the diet - 8-10 essential amino acids Nonessential (dispensable) Amino Acid - One that the body can make in large enough quantities (Made from essential amino acids) - Not necessary to consume these in the diet - 10-12 nonessential amino acids ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ Essential Amino Acids Nonessential Amino Acids -Phenylalanine -Valine -Threonine -Tryptophan -Isoleucine -Methionine -Histidine -Arginine -Leucine -Lysine -Alanine -Asparagine -Aspartic acid -Cysteine -Glutamic acid -Glutamine -Glycine -Proline -Serine -Tyrosine Conditionally essential Amino Acids -Cysteine -Glutamine -Tyrosine Used in body organs and soft tissues Enormous functional diversity Cell membrane structure and function Enzymes Hormones and other chemical messengers Immune factors (antibodies) Fluid Balance Transport Source of energy Structural and Mechanical – Collagen in bone and skin; Keratin in hair and nails; Motor proteins, which make muscles work Enzymes Proteins that catalyze (speed up) chemical reactions without being used up or destroyed in the process Anabolic (putting things together) and catabolic (breaking things down) functions Eg. Digestion – salivary amylase Hormones Chemical messages that are made in one part of the body but act on cells in other parts of the body Eg. Insulin, some reproductive hormones Immune Function Antibodies are proteins that attack and inactivate bacteria and viruses that cause infection Fluid Balance Proteins in the blood help to maintain appropriate fluid levels in the vascular system. Fluid is forced into tissue spaces by blood pressure generated by pumping action of heart. Transport substances in the blood Lipoproteins (transport lipids) Hemoglobin ( transports oxygen and carbon dioxide) Transports materials across cell membranes Proteins are the last to be used for energy Occurs in starvation and low carbohydrate diets When the body has excess protein stores, some amino acids are converted and stored as fat in body Sources of protein Functions include; Provide energy Efficient storage of energy (adipose tissue) Insulation Essential nutrients required for; metabolic and physiological processes, structural and functional integrity of cell membranes Control body temperature Physical protection to internal organs Transport fat soluble vitamins Flavour and mouth feel Simplest form – composed of a chain of carbons with hydrogen atoms attached, methyl group and a carboxylic group Methyl group Acid group Double Bond High energy component – 9 kcal per gram Most important contain 16-18 carbons Whether a fat is saturated, monosaturated or polysaturated depends on the location of the double bond Only single bonds High melting temperature Solid at room temperature Chemically stable Examples include animal fats and their products Linked with risk of cardiovascular disease Contain one double bond Usually liquid at room temperature Examples include olive oil, rapeseed Oil, nuts and seeds Most beneficial type of fatty acid Lower LDL cholesterol Contain 2 or more double bonds Liquid at room temperature Susceptible to oxidation Omega 3 and 6 Polyunsaturated fatty acids are needed in brain development Processed margarines contain significant amounts of trans fat Same adverse affects as saturated fatty acids Wax like substance Produced by the liver Belongs to steroid family Important to limit dietary cholesterol Cholesterol is essential to life required for synthesis of bile acids steroid hormones and vitamin D Less than 35% of energy intake should come from fats No more than 10% from Saturated fatty acids No more than 12% Monounsaturated fatty acids No more than 6% N-6 Polyunsaturated fatty acids (PUFA) 0.2g/day minimum N-3 Polyunsaturated fatty acids (PUFA) <2% Trans fats ◦ Certain populations may need higher intakes of n-3 Reduced fat = at least 25% less fat than the standard product Low fat food = <3g fat/100g or 100ml Fat free = <0.15g fat/100g or 100ml Essential organic substances, they yield no energy, but facilitate energy-yielding chemical reactions Essential nutrients in maintenance of normal health Obtained from food because the body can’t make them But you need only small amounts (micronutrients) because the body uses them without breaking them down, unlike what happens to carbohydrates and other macronutrients 13 compounds have been classified as vitamins Vitamins A, D, E, and K, the four fat-soluble vitamins, tend to accumulate in the body Vitamin C and the eight B vitamins (biotin, folate, niacin, pantothenic acid, riboflavin, thiamin, vitamin B6, and vitamin B12) dissolve in water, so excess amounts are excreted (watersoluble vitamins) Vitamin A = Retinol, retinaldehyde, retonoic acid (performed) and carotenoids (provitamin A) Vitamin B1 = Thiamin Vitamin B2 = Riboflavin Vitamin B6 = Pyridoxine, pyridoxal, pyridoxamine Vitamin B12 = Cobalamin Vitamin C = Ascorbic Acid Vitamin D = Calciferol Vitamin E = Tocopherol, tocotrienol Vitamin K = Phylloquinone Function – Promote Vision and Growth, prevent drying of skin and eyes Food Sources – Performed (Liver, fish oils, fortified milk and eggs) Proformed (Dark leafy green, yellow orange vegetables & fruits Deficiency – Cause night blindness, skin changes and nutritional anaemia Those at risk – Urban poor, breast fed infants (mother’s poor diet) elderly, schoolchildren (poor veg. intake) Function – Calcium absorption, regulate bone metabolism, healthy immune system Food Sources – Herring, eel, salmon, tuna, milk, some fortified cereals, pork sausage, egg yolk (sunlight) Deficiency – Rickets in children, Osteomalacia in adults Those at risk – Elderly (stay indoors) People living in Northern Climate, People with fat malabsorption Function – Antioxidant, protects cells from attacks by free radicals, role in iron metabolism Food Sources – Vegetable oils, nuts, seeds, green leafy vegetables and a variety of fish Deficiency – Nerve degeneration Those at risk – Premature infants, smokers, people with fat malabsorption Function – Role in coagulation process (blood-clotting) Food Sources – Liver, green leafy vegetables, broccoli, peas and green beans Deficiency – Bleeding disorders, fractures Those at risk – People taking antibiotics for long periods Function – Aids in calcium / iron absorption, immune functions Food Sources – Citrus fruits, potatoes, green peppers, cauliflower, broccoli, strawberries Deficiency – Scurvy, fatigue, bleeding gums and joints Those at risk – Infants, elderly, alcoholics, smokers The major minerals present in the body include sodium, potassium, chloride, calcium, magnesium, phosphorus, and sulfur. Trace minerals are present (and required) in very small amounts in the body. The most important trace minerals are iron, zinc, copper, chromium, fluoride, iodine, selenium and manganese. Adults are 60-70% water Functions - Maintain the health and integrity of every cell in the body.Help eliminate by-products of the body’s metabolism, excess electrolytes (sodium & potassium). Regulate body temperature through sweating. Dehydration occurs when the water content of the body is too low. This is easily fixed by increasing fluid intake. Symptoms of dehydration include headaches, lethargy, mood changes and slow responses, dry nasal passages, dry or cracked lips, darkcoloured urine, weakness, tiredness, confusion and hallucinations. Recommended intake depends on age, hot environment etc. Averages between 6-10 cups/day