Nutrition -Unit 3 Specific Nutrients in foods.pdf

Unit 3 Specific Nutrients in Foods By Ms G.H.L Wijesundara Grade I Nursing Tutor College of Nursing Rathnapura  Outline Classification of Foods Nutrition Definition of Nutrients Protein...

Unit 3 Specific Nutrients in Foods By Ms G.H.L Wijesundara Grade I Nursing Tutor College of Nursing Rathnapura  Outline Classification of Foods Nutrition Definition of Nutrients Protein Carbohydrates Fat 2  Learning objectives By the end of this unit you should be able to,  Identify the importance of Nutrients 3  Classification of Foods Food Is any substance consumed to provide nutritional support for an organism. There are many ways of Classifying foods: 1. Classification by Origin I). Foods of animal origin II).Foods of vegetable origin 4  Classification of Foods ctd.. 2. Classification of chemical Composition: I. Proteins II. Fats III. Carbohydrates IV. Vitamins V. Minerals 5  Classification of Foods ctd.. 3. Classification of Predominant Function I. Body Building Foods Eg: Milk,meat,poultry,fish, eggs, pulses,peas,nuts,etc II. Energy giving foods Eg: Cereals, Sugars, roots, and tubers ,fats and oils. III. Protective foods Eg: Vegetables,fruits milk 6  Classification of Foods ctd.. 4.Classification by Nutritive value: I. Cereals and Millets VI. Animal Foods II. Pulses ( legumes) VII. Fats and oil III. Vegetables VIII. Sugar and jiggery IV. Nuts and oilseeds IX. Condiments and spices V. Fruits X. Miscellaneous foods 7 Proteins 8  Nutrition Definition “ Science of food; the nutrients and the substances therein ; there action and interaction and balance in relation to health and disease; and the process by which organism ( eg human body)ingests, digests, absorbs , transports ,utilizes and excrete for substances”( American Medical Association) 9  Definition of Nutrients Nutrition are organic and inorganic complexes contained in food Through the foods we eat ,gain 50 different nutrients Most natural foods contain more than one nutrient. These may be divided into: 1. Macro Nutrients 2. Micro Nutrients 10  Macro Nutrients Carbohydrates , Proteins ,lipids and water are needed in large amount - called Macro nutrients Contribution To Energy Intake Carbohydrates - 65%- 80% Fats - 10%- 30 % Proteins - 7 % - 15% 11  Micro Nutrients Viatamins and minarals are needed in small amount in the diet called Micro Nutrients Fraction of a milligram to several grams 12 Micro Nutrients 13 Protein 14 15  Protein Derived from the Greek word „‟ proteios‘‟ meaning „‘of prime importance - “to take first place” Proteins contains C, H, O and N. Also may present S&P Proteins are larger & more complex than carbohydrates & fats 16  Protein Some proteins also contain Iron and occasionally other elements Protein contribute 20% of the body weight element Protein is found throughout the body—in muscle, bone, skin, hair, and virtually every other body part or tissue. 17  Protein It makes up the enzymes that power many chemical reactions and the hemoglobin that carries oxygen in your blood Amino acids, the building blocks of proteins, are arranged in various sequences & geometric pattern. 18  Protein Such combination of amino acids determines the physiological function of each protein The amino acid can link together & this linkage is called a peptide bond 19 Amino acids Variant group 20 Amino acids ctd. 21 22  Protein ctd.. Two amino acids linked together - Dipeptides Three amino acids linked together - Tripeptides Additional amino acids are added - Polypeptides 23  Protein ctd.. Most proteins are polypeptides with 100-300 amino acids There are 20 essential & non- essential amino acids required by the human body Among these 9 are essential & are required in the diet 24  Essential Amino acid (EAA) 1. Histidine 2. Isoleucine 3. Leucine 4. Lysine 5. Methionine 6. Phenylalanine 7. Threonine 8. Tryptophan 9. Valine 25  Protein ctd.. Non essential amino acids are produced endogenously ( in the body) from other dietary amino acids which have not been used for protein synthesis Non essential Amino Acids Alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine 26  Metabolism of Proteins Proteins are converted by enzymes of the gastric, pancreatic and intestinal juices into amino acids These are absorbed by the villi of the small intestines & carried by the portal vein to the liver The waste products of protein metabolism are urea, uric acid & creatinine 27 Digestion of Proteins 28  Digestion of Proteins The process of protein digestion is more complex than the digestion of CHO In the presence of food, proenzymes are activated to functioning enzymes 29  Digestion of Proteins Proenzyme is an inactive form of an enzyme. It requires a biochemical change (presence of acidic media…..) for it to become an active enzyme. The first step of mechanical digestion (physically breaking down food substances into smaller particles) taken place in mouth. 30  Digestion of Proteins Chemical digestion enzymes break the chemical bonds that hold food particles together begins in the stomach by gastric Hcl. 31  Digestion of Proteins In the stomach (hydrolyses into small polypeptides) Pepsin Protein Small polypeptides Renin Milk & milk proteins casein 32  Digestion of Proteins ctd. In the duodenum Trypsin in pancreatic juice converts polypeptides into a mixture of amino acids, dipeptides & tripeptides 33  Absorption of Proteins Absorption of digested food takes place entirely in the small intestines through two channels; 1. Capillary blood vessels 2. Lymphatic vessels of the villi on the inner surface of the small intestine 34 Absorption of Proteins 35  Absorption of Proteins Amino acid absorption is accomplished through active transport mechanism which require energy This amino acids are absorbed into the blood through the capillaries Blood vessels then go into the portal vein to the liver 36  Absorption of Proteins Formation of urea The liver receives amino acids which have been absorbed by the blood In the liver cells de-amination takes place  De-amination means the nitrogen is separated from the amino acid part & the ammonia converted into urea.  Urea is removed by the liver  It is taken to the kidneys & excreted in the urine  The remaining part is used by tissue for repair & body fluid 37 Classification Of Protein Fibrous Structure Globular Intermediate Simple Composition Conjugated Derived Structural proteins/ Enzymes/ Hormones Function Transport & contractile Proteins/ Pigments/ Storage Proteins/ Toxins Classification of Protein According to the Structure Based on the structure, proteins are classified in to 3 groups A. Fibrous Proteins B. Globular Proteins C. Intermediate Proteins  Classification of Protein According to the Structure ctd… A. Fibrous Proteins They are linear (long fibrous) in shape Secondary structure is the most important functional structure of fibrous proteins Usually, these proteins are do not have tertiary structures Physically fibrous proteins are very tough and strong Fibrous Proteins ctd…. They are insoluble in the water Long parallel polypeptide chains cross linked at regular intervals Fibrous proteins form long fibres or sheaths Functions of fibrous proteins: perform the structural functions in the cells Eg : Collagen, Myosin, Silk and Keratin  B.Globular Proteins Globular proteins are spherical or globular in shape The polypeptide chain is tightly folded in to spherical shapes Tertiary structure is the most important functional structure in globular protein Physically they are soft than fibrous proteins They are readily soluble in water  Globular Proteins ctd… Most of the proteins in the cells belong to the category of globular proteins Functions: from enzymes, antibodies and some hormones Example: insulin, haemoglobin, DNA polymerase and RNA polymerase C. Intermediate Proteins Their structure is intermediate to linear and globular structures They are short and more or less linear shaped proteins Unlike fibrous proteins, they are soluble in water Function: blood clotting proteins Example: fibrinogen Classification of Protein According to the Composition ctd… 1. Simple Proteins On hydrolysis they yield only the amino acids and occasional small carbohydrate compounds. Eg: Albumin, globulins, glutelins, albuminoids, histones and protamines.  Classification of Protein According to the Composition ctd 2. Conjugated Proteins There are simple proteins combined with some non-protein material in the body.  Eg:Nucleoproteins, glycoproteins, phosphoproteins, haemoglobins and lecithoproteins 46  Classification of Protein According to the Composition ctd 3. Derived proteins These are proteins derived from simple or conjugated proteins by physical or chemical means. Eg :Denatured proteins and peptides 47  Classification of Protein According to the Function. a) Structural proteins b) Enzymes c) Hormones d) Respiratory pigments e) Transport proteins f) Contractile proteins g) Storage proteins h) Toxins 48  Classification of Protein According to the Function ctd a)Structural proteins Form the component of the connective tissue, bone, tendons, cartilage, skin, feathers, hairs Most of them are fibrous proteins and are insoluble in water Eg : Collagen, Keratine and Elastin 49  Classification of Protein According to the Function ctd b)Enzymes They are the biological catalysts Enzymes reduce the activation energy of reactants and speed – up the metabolic reaction in the cells Most of them are globular conjugated proteins Eg: DNA polymerase, nitrogenase, lipase 50  Classification of Protein According to the Function ctd c)Hormones: They include the proteinaceous hormones in the cells Eg: insulin, Glucagon, ACH 51  Classification of Protein According to the Function ctd d) Respiratory Pigments They are color proteins All of them are conjugated proteins and they contain pigments (chrome) as their prosthetic group Eg: Haemoglobin, Myoglobin 52  Classification of Protein According to the Function ctd e) Transport proteins They transport the material in the cells They form channels in the plasma membrane They also form one of the components of blood and lymph in animals Eg: Serum albumin 53  Classification of Protein According to the Function ctd f) Contractile proteins They are the force generators of muscles They can contract with the expense of energy from ATP molecules Eg: Actin, Myosin 54  Classification of Protein According to the Function ctd g) Storage proteins They act ad the store of metal irons and amino acids in the cells Found in seeds, egg and milk Abundantly seen in pulses (legume seeds) Eg: ferritin which stores iron, casein, albumin, Gluten of wheat 55  Classification of Protein According to the Function ctd h) Toxins They are toxin proteins Eg: snake venom 56  Functions of Proteins Proteins are needed by the body for; 1. Body building, repair & maintenance of body tissues 57  Functions of Proteins Protein Functions collagen Formation of scars, tendons, ligaments, bones & teeth Contractile proteins Contractile proteins Formation of muscle tissues Cell membrane proteins Formation of a barrier around cells 58  Functions of Proteins ctd 2.Compounds in regulation of body functions; Antibodies Hormones Plasma proteins Coagulation factors Hemoglobin Enzymes 59  Functions of Proteins ctd 3.Source of energy –(Supply energy 4 kcal per one gram) Instance of CHO & fat shortage, food protein & body protein are broken to supply energy 4. Proteins are connected with the immune mechanism of the body (eg. Antibodies) 60  Quality of Proteins The major factor that determines protein quality is the completeness & adequacy of essential amino acids Another factor is digestibility of the protein ―A Biologically complete proteins‖, which contains all the essential amino acids in roughly the proportions needed by the human 61  Properties of Protein 1.Amphoteric Nature - They act as both acids and bases(Ampholites) 2.Solubility -Each protein has a definite and characteristic solubility in a solution of known salt concentration and PH Eg:Albumins - soluble in water Globulins - soluble in Nacl 62  Properties of Protein 3.Colloidal Nature of Protein Solution - Proteins have large molecular weight - They do not pass through semipermeable membranes -This property is great physiological importance 63  Sources of Proteins 1. Protein from animal sources; Meat, fish, poultry/chicken, eggs, milk, cheese Animal proteins contain all the essential amino acids (EAA) in adequate amounts. Its called first class protein Egg protein has the highest biological value & digestibility The proteins of meat are in a high biological value Also meat are rich in iron, phosphorus & vitamin B12 64  Sources of Proteins Biological value (BV) refers to the proportion of protein retained in the body for growth and/or maintenance and expressed in percent of nitrogen absorbed. High biological value means all absorbed amounts are retained in body. Biological Value= Nutrition retained *100 Nutrition absorbed 65  Sources of Proteins ctd 2.Protein from vegetable sources; Pulses, beans, nuts & cereals They are poor in essential amino acids (EAA) In developing countries cereals & pulses are the main sources of dietary protein because they are cheap & easily available Pulses- dhal, soybeans Nuts- peanuts, cereals, wheat 66  Sources of Proteins ctd 3.Milk products Pasteurization A temperature based preservation technique that removes or destroys some forms of pathogenic microorganisms. The most resistant forms and some spores remain present. 63. C for 30 mins or 73.C for 15 seconds in used Pasteurized milk will keep for 48 hrs at 20.C or 72 hrs at 15.C 67  Sources of Proteins ctd Fermented milk Milk is fermented by different kind of bacteria called Lactobacilli or Bifidobacteria. These bacteria produce folate Mineral content also high in fermented milk Digestibility is high & due to probiotic effects protect from other causing bacteria 68  Sources of Proteins Curds & yoghurt Cheese (most water is removed) 69  Health Concerns Related to Protein Intake 1. Protein –Energy malnutrition (PEM)  Condition resulting from insufficient amount of energy and protein which eventually result in body wasting and an increased susceptibility to infection and diseases. 70  Health Concerns Related to Protein Intake ctd  Marasmus - sever deficit of energy and protein - causes extreme loss of fat stores,muscle mass, and body weight 71 Marasmus 72  Health Concerns Related to Protein Intake ctd. Kwarshiorkor - occur primarily in young children who have an existing disease and consume a marginal amount of energy and severely insufficient protein - It result in edema,poor growth ,weaknessand increased susceptibility to further infection and disease. 73 Kwarshiorkor 74  Health Concerns Related to Protein Intake ctd. 2.High protein diet - Diets containing excessive or disproportionate amount do not provide additional benefit. 3. Vegetarian diet - increase the varieties of pulses - Calcium fortified food intake 75  Health Concerns Related to Protein Intake ctd. Recommended intake The adult RDA for protein is 0.8g per kg of healthy body weight. 76  Summary Amino acids are building block of proteins Of the 20 amino acids needed by the body, 9 must provided in diet ( essential) other 11 can synthesized by the body( non essential) Individual Amino acids are linked together to form proteins Almost all animal products are rich source of protein. Protein digestion start from the stomach Adult RDA for Protein 0.8g/kg body weight 77  Summary Important body components -muscle tissue,connective tissue…. Undernutrition can lead to PEM in form of kwarshiorkor and marasmus Vegetarian diet becoming more popular.. 78  Assignment 2 According to My plate concept in Sri Lanka what is the proportion of Protein intake for healthy adult ? 79 Carbohydrates 80 81  2.Carbohydrates(CHO) One of the major component of food Main source of energy, providing 4kcal per one gram During photosynthesis, plant convert CO2 & water into carbohydrates (glucose), a process requiring sunlight & chlorophyll 82 Carbohydrates(CHO) ctd.. 83  Carbohydrates(CHO) ctd. The CHO are present in various forms The general formula for carbohydreates is (CH2O)n or Cn(H2O)n CHO are found in all plant foods The only animal product the contains significant amount of CHO is milk 84  Carbohydrates(CHO) ctd. There are three main sources of carbohydrates 1. Starch (found in cereals, roots & tubers) 2. Sugar 3. Cellulose (indigestible component of CHO, contributes to dietary fibre) 85  Classification of Carbohydrates Classified into 2 groups 1. Simple Carbohydrates I. Monosaccharides (glucose, fructose, galactose) II. Disaccharides (maltose, lactose, sucrose) 2. Complex carbohydrates I. Polysaccharides (starch, glycogen, cellulose-dietary fiber) 86  Classification of Carbohydrates ctd 1. Monosaccharides or simple sugars CHO contain carbon, hydrogen & oxygen atoms in the defined proportion of one part carbon to one part water The general chemical formula for the basic unit of CHO- glucose is C6H12O6 This monosaccharide- Glucose is the principle building block of all carbohydrates. 87  Classification of Carbohydrates ctd. Fructose commonly found in fruits Galactose is a component of lactose All three have the same chemical formula, with only slight variation in the positioning of some atoms These minor differences cause for their sweetness 88  Classification of Carbohydrates ctd 2.Disaccharides There are three common disaccharides 1. Maltose is formed from two molecules of Glucose. It occurs as a breakdown products of starch 2. Lactose is formed from a molecule of glucose & galactose. It is the principal CHO found in milk 3. Sucrose is formed from a molecule of glucose & fructose. Commonly known as table sugar 89  Classification of Carbohydrates ctd 3.Polysaccharides The complex CHO are polysaccharides 1. Starch - major type found in plants This consists of hundreds or even thousands of glucose molecules joined together in long branched chains Starch can found in Cereals (rice, wheat, barley, millets) Roots (Carrots, beetroot) Tubers (sweet potatoes, potato, manioc) 90  Classification of Carbohydrates ctd 2.Glycogen This is the storage CHO found in the liver & muscles Chemically, it is very similar to starch Helps to maintain body energy 91  Classification of Carbohydrates ctd Also helps to control the blood sugar level Glucose Insulin Glycogen (glycogenesis) Glycogen Glucagon Glucose (glycogenolysis) 92  Classification of Carbohydrates ctd 3.Fibers Plants contain an assortment of other substances lumped together as dietary fiber/ roughage Fiber mainly consists of cellulose & hemicellulose This part of carbohydrates are not digested by human digestive juices/ enzymes They are left unchanged after digestion Some are partially broken down by bacterial enzymes in the colon. (eg; soluble fibers) 93  Classification of Carbohydrates ctd There is an association between high fiber foods & a low incidence of diseases as cardiovascular disease, colon cancer, constipation, diverticular disease, appendicitis, hemorrhoids & obesity. Fiber is not digested in the small intestine, passes to the colon 94  Classification of Carbohydrates ctd Around 70-80% of fiber broken down by bacterial fermentation The fiber is not broken down mainly insoluble fiber absorb a considerable amount of water, causes large increase in fecal bulk 95  Types of Fibers Types of fibers (according to the water solubility) 1. Soluble fibers (pectins, hemicellulose, gums & mucilage) Soluble fiber can be partially digested by bacteria in the colon. 96  Types of Fibers 2. Insoluble fibers (cellulose, some forms of hemicellulose) These are more resistant to breakdown by bacterial enzymes than is soluble fiber 97  Functions of Fibers 1.The fiber absorbs water, & this increases the bulk of the stool & helps to reduce the tendency to constipation by encouraging bowel movements 2. The cholesterol lowering effect of certain types of fibers appears firmly established 98  Functions of Fibers ctd 3. Fiber may also have a role in weight reduction, people who eat well balanced diets obtain enough roughage 4.Fiber rich diets require longer chewing time, so the greater salivation will positively affects oral hygiene 5. Reduce incidence of colonic carcinoma 6. Decreases diarrhea 99  Important terms used in CHO Blood sugar refers to glucose in the blood stream Dextrose is commonly used on food labels, & is the same compound as glucose Dextrin is a short chain of glucose units resulting from the partial hydrolysis of starch, it is often used as a thickening agent in foods Refined sugars are white table sugar & contain virtually pure simple CHO 100  Carbohydrate Digestion Saliva contains an enzyme called amylase, which starts the process of starch digestion by breaking it down to small polysaccharides & maltose Digestion stops in the stomach as amylase is inactivated by stomach acidity 101  Carbohydrate Digestion ctd. The major site of CHO digestion is the small intestine The pancreas secrets enzymes into the small intestine via the pancreatic duct 102 103  Carbohydrate Digestion ctd. One enzyme is amylase which performs the same role as salivary amylase Enzymes on the surface of the small intestinal cells hydrolyze disaccharides Maltase Maltose Glucose Sucrose Sucrase Glucose + Fructose Lactose Lactase Glucose + Galactose 104  Carbohydrate Digestion ctd Within one to four hours of digestion, the CHO have been fully digested The monosaccharides resulting from digestion are then absorbed in the small intestine & travel in the blood to the liver In the liver fructose & galactose are converted to glucose Dietary fiber is not digested in the small intestine & passes to the colon 105  Carbohydrate Digestion ctd In that organ bacteria digest much of the soluble fiber The insoluble fiber, producing short- chain fatty acids These substances are absorbed in the colon & are a significant source of energy 106  Functions of Carbohydrates 1. They are the main sources of energy The body tissues require a constant supply of glucose for all metabolic functions CHO must be consumed daily to meet energy needs & to maintain a sufficient glycogen store 110 g of glycogen is stored in the liver 225g in the muscles 10g as blood sugar 107  Functions of Carbohydrates ctd 2.CHO serves to maintain the blood glucose level By circulating the blood stream & supplying energy to all body cells 108  Functions of Carbohydrates ctd 3.CHO are essential to the normal functioning of some specialized body cells The nerve tissues of the brains & of the central nervous system, the lungs & the red blood cells These cells require glucose as the sole energy source 109  Functions of Carbohydrates ctd 4.CHO as a protein sparer Body protein can be converted to glucose as a source of energy when there is an insufficiency of CHO The primary function of proteins in the body is for synthesis & maintenance of body tissues & fluids 110  Functions of Carbohydrates ctd In order to allow optimal functioning of the proteins sufficient CHO are needed to spare proteins from being used for energy This is important in low-calorie diets, when enough CHO should be prevent muscle loss 111  Functions of Carbohydrates ctd Protein sparing (amino acid sparing) is the process by which the body derives energy from sources other than protein. Such sources can include fatty tissues, dietary fats and carbohydrates In CHO, there is no storage molecule of amino acids, this process requires the destruction of proteins, primarily from muscle tissue. 112  Functions of Carbohydrates ctd The presence of adequate glucose basically spares the breakdown of proteins from being used to make glucose needed by the body. 113  Functions of Carbohydrates ctd 5. CHO prevents ketosis Ketosis is a process that happens when your body doesn't have enough carbohydrates to burn for energy. When there is insufficient CHO, large amount of fats are broken down energy- more than the body is equipped to handle. As a result fats are incompletely oxidized, & ketones are produced 114  Functions of Carbohydrates ctd The ketone bodies are not excreted rapidly enough, & are accumulated; this causes ketosis The complications of ketosis are dehydration, changes in chemical actions, coma & death 115  Glycemic index (GI) A method of classifying food according to their potential for raising blood glucose The speed at which the carbohydrates in a food are digested to glucose is called the food‟s glycaemic index (GI) value A number from 0- 100 assigned to a food, with pure glucose arbitrarily given the value of 100 which represents the relatives rise in the blood glucose level two hours after consuming that food 116 117 118  Glycaemic index Low GI foods are broken down slowly. The glucose, or energy, from their carbohydrates is releas ed into the blood over several hours. Low GI foods prolong digestion due to their slow break down and may help with you feel full for longer. High GI foods are digested rapidly and give you a blood glucose spike. 119  Glycaemic index Slow digestion is better than fast digestion, so low GI foods are generally better than high GI foods. It helps keeps your blood glucose levels stable. This is important if you have diabetes It‟s important to look at the overall nutritional value and carbohydrate content of a food item, not just the GI.  Junk food with a low GI is still junk food. 120  CHO Metabolism When a person take food into his mouth the food is swallowed with saliva In the saliva, an enzyme called ‗ptylin‘ is present Ptylin acts on cooked starches & simple sugars, converts them into maltose The action of ptylin continuous in the stomach for about 20 minutes or until the food is rendered acid by the action of gastric juices (ptylin is an 121 alkaline medium)  CHO Metabolism Then the food is passed through pyloric opening into the duodenum The food is partly neutralized by the action of the alkaline juice of the duodenum, pancreas, bile, amylase Amylase is an enzyme present in the pancreatic juice Amylase is more powerful than ptylin & acts on uncooked as well as cooked starches & converts them into disaccharides 122 As the foods comes into the last part of the small intestine (ileum), three enzymes act on carbohydrates completing the digestion of starches by converting disaccharides into monosaccharides Maltase Maltose Glucose Sucrase Sucrose Glucose + Fructose Lactose Lactase Glucose + Galactose 123  CHO Absorption Absorption of digested food takes place entirely in the small intestines through two channels; 1. Capillary blood vessels 2. Lymphatic vessels of the villi on the inner surface of the small intestine This simple sugar is absorbed by the villi of the small intestine passes into the blood capillaries, and is carried by the portal vein to the liver, 124 where excess sugar is stored as glycogen 125  CHO Absorption The use of glucose is to serve as the main body fuel for the production of energy for work & heat The glucose required for immediate use is carried straight through the liver into the hepatic veins & inferior vena cava & enters the circulation 126  CHO Absorption Any excess not required for the body‘s immediate needs is converted by the liver cells into glycogen, which is insoluble & is stored in the liver until required for use 127  CHO Absorption When sugar is needed by the body, the glycogen is converted back into glucose, which the body fluids dissolve, so that it passes into the blood stream Glucose is specially required by the most active tissues of the body, the muscles & glands, but all tissues need it to some extent The muscles, like the liver are able to store it to a slight extent in the form of glycogen 128  CHO Absorption Glucose is burnt to produce energy (complete combustion) But more energy is released by the process of burning, that is required for the work of the muscles & the excess energy is used to build up glycogen again 129  CHO Absorption The waste products of the combustion of the carbohydrates are CO2 & water, which are carried away by the blood stream & excreted from the body The lungs excrete the CO2 & water, water is also got rid of by the skin & kidneys 130  CHO Absorption Combustion of glucose may be incomplete if there is deficient O2 supply, & gives rise to acid bodies which cause the pain of acute cramps The acids cause the blood vessels to dilate, which increases the blood supply & thus the O2 supply, & resulting in the passing off the pain, as combustion can then be completed The metabolism of CHO is controlled by insulin, the internal secretion of the pancreas 131  Non Nutritive Sweeteners Various natural non-sugar sweeteners and artificial sweeteners are used to produce food and drink.  Eg :Saccharin,Aspartame,Neotame Increase cancer risk. 132  Non Nutritive Sweeteners Added sugar 133  Healthy Diet with Carbohydrates Added sugar Added sugar from foods can contribute to obesity, diabetes, and heart disease. Avoiding high-sugar foods by reading labels and cutting out... 134 4 grams of sugar = 1 teaspoon Keep this tip in mind when reading nutrition labels to better visualize just how much added sugar the product contains. For example, one 12-ounce can of cola contains 39 grams–almost 10 teaspoons of sugar! 135 Fats or Lipids 136 137  Fats or Lipids Lipids are organic compounds composed of C, H & small amount of oxygen The smallest unit called Fatty Acids Normally, lipids are insoluble in water To facilitate their transport they are bound to proteins thus forming „‘lipoprotein‘‘ 138 Fatty Acid General Structure for fatty acid. 139 Fatty Acid 140  Lipids Ctd… The terms lipids & fats are often used interchangeably Fats belong to a subgroup of lipids This subgroup is called triglycerides Triglycerides make up 95% of dietary lipids 141  Lipids Ctd… Fats & oils include to triglycerides & both are concentrated source of energy. Fats are usually solid, & oils are usually liquid at room temperature Most lipids are soluble in organic solvents such as chloroform, ether or benzene 142  Lipids Ctd… The other 5% is contributed by phospholipids, sterols, fat soluble vitamins, waxes & minor complex lipid compounds The triglyceride is composed of a glycerol molecule & three fatty acids 5/24/2024 143  Lipids Ctd… Each chain has a carboxylic acid at one end & a methyl group at the other Monoglycerides can be found in the human GI tract after a heavy fatty meal, as one of the product of fat digestion 144  Lipids Ctd… 5/24/2024 145  Lipids Ctd… If one fatty acid is attached to a glycerol molecule, formed Monoglyceride If two fatty acids are attached & formed diglycerides 146  Lipids Ctd… Monoglyceride & diglycerides are used as emulsifiers to give food a smooth texture Some fatty acids have the maximum amounts Hydrogen & called saturated fatty acids 147 148  Lipids Ctd… Others have less H & instead have one or more double bonds & called unsaturated fatty acids Monounsaturated fatty acids have one double bond (Olive, peanut, canola oils, Avocados, Nuts…..) 149 … 150  Lipids Ctd… Polyunsaturated fatty acids have 2 or more double bonds. There are 2 types as Omega-3 and omega-6 fatty acids Eg; Soybean oil, walnuts, fatty fish and shellfish 151 152  Lipids Ctd… Fatty acids are the building blocks of lipid Fatty acids also can be classified according to the chain length  Short chain fatty acids ( 4- 8 carbons)  Medium chain fatty acids (10- 14 carbons)  Long chain fatty acids (16- 22 carbons) 153  Lipids Ctd… The length of Carbon chain & the degree of unsaturation of fatty acids determine the hardness of a fat at room temperature Palmitic acid & linoleic acid are the most abundant saturated & polyunsaturated fatty acids 154  Lipids Con… Fatty acid No. of carbon No of Consistency at atoms double room bonds temperature Palmitic 16 0 Solid Stearic 18 0 Solid Oleic 18 1 Liquid Linoleic 18 2 Liquid Linolenic 18 3 Liquid Arachidonic 20 4 Liquid 5/24/2024 155  Phospholipids These are found in almost all cells as a major constituent of cell membranes They have the ability to attract water soluble as well as fat soluble substances 5/24/2024 156  Phospholipids So they help to facilitate the passage of fats in & out of cells through the cell membranes Eg; lecithin (is a type of phospholipid which consists of glycerol , two fatty acids , a phosphate group and choline) 157  Lipids in Diets Animal fats are usually rich in saturated fats Coconut oil also a largely in saturated. But it is medium chain fatty acids rather than long chain as in meat Monounsaturated fats are present in many foods (sesame seeds, peanuts, olive oil, avocado) 5/24/2024 158  Lipids in Diets Animal Fat Plant Fat Curd Avocado Cheese Nuts ( cashew) Egg Olive oil Yoghurt Pork Fatty beef mackerel 5/24/2024 159  Cholesterol Is a sterol which is a lipid but do not contribute energy to the body About 80% of body cholesterol is synthesized in the body (mainly liver & intestine) & is called endogenous cholesterol Cholesterol is also found in food of animal origin Plants do not make cholesterol 5/24/2024 160  Cholesterol In the body, cholesterol is used as; An essential component for cell membranes Is the precursor for the synthesis of bile acids, hormones & vitamin D 5/24/2024 161  Lipoprotein To facilitate lipid transport, they are bound to proteins thus forming „‘lipoprotein‘‘ Different lipoproteins have been separated by ultra centrifugation according their densities 162  Lipoprotein ctd.. Chylomicrons- the lightest lipoprotein This can find in body after eat fat meal For lipid profile keep fasting for 12 hours to get chylomicron zero 5/24/2024 163  Lipoprotein Ctd… Very Low Density Lipoprotein (VLDL) These are form in the liver The liver picks up various body compounds from the blood & converts them to triglycerides, cholesterol & fatty acids VLDL are composed of a high proportion of triglyceride It transports fat from the liver to other tissues 5/24/2024 164  Lipoprotein Ctd… Low Density Lipoprotein (LDL) They contain little triglyceride but much cholesterol As LDL circulate throughout the body, peripheral tissues pick up cholesterol 5/24/2024 165  Lipoprotein Ctd… High Density Lipoprotein (HDL) These contain much protein HDL carries cholesterol from peripheral tissue to liver 166  Essential Fatty acids The body is unable to produce these types of fatty acids in amounts sufficient for normal functioning Therefore this nutrient must be supplied by the diet Two families of polyunsaturated fatty acids are; 1. Omega 3 fatty acid family 2. Omega 6 fatty acid family 5/24/2024 167  Essential Fatty acids The chemical difference between the 2 groups is the position of the endmost double bond from the methyl end of the fatty acid molecule 168 5/24/2024 169  Essential Fatty acids 1. Omega 3 fatty acid family -Linoleric acid (18 carbons, 3 double bonds) EPA (eicosapentaenoic acid) DHA (decosahexaenic acid) Sources- salmon, Tuna, Mackerel, Canola soybean oil 5/24/2024 170  Essential Fatty acids 2. Omega 6 fatty acid family - Linoleic acid (18 Carbons, 2 double bonds) - Arachidonic acid (20 carbons, 4 double bonds) Sources; Meats, sunflower, corn, passion seed, ginger 5/24/2024 171  Oxidation & hydrogenation Oxidation occurs when O2 combines with an unsaturated fatty acid at the double bond This gives the oil the unpleasant odour & flavor 5/24/2024 172  Oxidation & Hydrogenation ctd.. Hydrogenation- Hydrogen is added to unsaturated oils to reduce the number of double bonds, making them more saturated & resistant to oxidation During hydrogenation, transformation of double bonds from a cis to trans form. Trans fat have some health effects as saturated fats 173  Oxidation & hydrogenation ctd. Unsaturated fats can be either cis fats or trans fats. While cis fats are beneficial and can promote good cholesterol, trans fats are considered harmful to cardiovascular health 5/24/2024 174  Oxidation & hydrogenation ctd.. The difference between cis and trans fatty acids is; The cis fatty acids have two hydrogen atoms attached to the double bond in the same side of the carbon chain The trans fatty acids have the two hydrogen atoms bonded to the double bond in the opposite sides of the carbon chain 175 5/24/2024 176  Functions of lipids in body 1) A major source of energy 2) A physical protector for sensitive tissues such as the kidneys 5/24/2024 177  Functions of lipids in body 3.Phospholipids & cholesterol are essential components of cell membranes 178  Functions of lipids in body 4.Cholesterol is used in the manufacture vitamin D, sex hormones 5.DHA (docosahexaenoic acid) for brain & retina development during rapid growth 6.EPA (eicosapentaenoic acid) may lower the risk of cardiovascular diseases 5/24/2024 179  Functions of lipids in body ctd.. 7.An insulator Lipids act as insulator under the skin and prevents heat from escaping out of the body. It makes sure the heat in our body does not escape and keeps us warm. 180  Digestion, Absorption & transport of lipids When a person takes his food it enters the stomach where gastric lipase produces slight hydrolysis of fat. Then the food enters duodenum where bile secretion emulsifies fat. 5/24/2024 181  Digestion, Absorption & transport of lipids Pancreatic lipase & intestinal lipase breakdown the fats into glycerol & fatty acids in the last part of the small intestine These glycerol & fatty acids absorbed by the ‗‘lacteals‘‘ & pass to the thoracic duct & enter the blood stream 182  Digestion, Absorption & transport of lipids In the blood, fat is carried to every cell of the body The liver assist in the oxidation of fats & prepares fats for deposition in the tissues In the tissues some of the fat is oxidized (in the presence of CHO) to give heat & energy 5/24/2024 183  Digestion, Absorption & transport of lipids Some of the fat is stored in the fat depots (There are two main adipose tissue depots in the body, subcutaneous and visceral adipose tissue) This stored fat contain vitamin A & D 184  Adipose tissues 5/24/2024 185  Digestion, Absorption & transport of lipids The waste products which result from the complete combustion of fat in the tissues are execrated  By the lungs as water & CO2  By the skin as sweats  By the kidneys (water) as urine 5/24/2024 186  Digestion, Absorption & transport of lipids If the combustion is incomplete, the acetone bodies formed also leave the body by the same routes. 187 188 Emulsifiers 189 Why do we add emulsifiers to food? 190 191 Emulsifiers are food additive molecules that act as a stabilizer for emulsions, preventing liquids that normally don't mix from separating.  Emulsifiers are abundant in the food supply, playing an important role in enhancing the appearance, texture, and shelf-life of many of the foods we consume today 192  A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. 5/24/2024 193  Assignment 3 Find out the diseases related to lipid metabolism. 194 Disorders Related To Lipid Metabolism 195  Disorders Related To Lipid Metabolism ctd.. Eskimos and Fatty acids?? 196 197  References  Bredbenner, C.B. , Moe,G., Berning, J, & Kelley,D. (2013) Wardlaw‟s Perspectives in Nutrition,( 10th edition).Mc Graw Hill education.  Indrani, T.K, Nursing Manual of Nutrition and Therapeutic Diet.Jeypee publishers.india  Introduction to healthy eating- Food Based Dietary Guidelines.(2021)nutrition division ministry of health.  Salins, O.(2004) Nutrition Guide(2nd edition). Jeypee publishers.india  http://doi.org/10.4038/sljm.v29i1.137 198 199