Week 6 Notes - Nutrition 101
Week 6 Notes - Nutrition 101 Nutrition 101
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This 9 page Class Notes was uploaded by Kennedy Patterson on Monday February 16, 2015. The Class Notes belongs to Nutrition 101 at University of Alabama - Tuscaloosa taught by Lori Greene in Spring2015. Since its upload, it has received 191 views. For similar materials see Nutrition 101-001 Intro Human Nutrition in Nutrition and Food Sciences at University of Alabama - Tuscaloosa.
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Date Created: 02/16/15
Nutrition 101 Proteins amp Lipids Week 6 291521 115 Structures of Protein Made up of amino acids Amino acids contain nitrogen N carbon C hydrogen H and oxygen 0 All amino acids have the same basic structure Side group 0 Central carbon atom vanes 0 Hydrogen atom H 0 Acid group COOH Amino H N C O H group H H Acid 0 Amino Group NH2 0 Side group varies with each amino acid Proteins more complex that carbs or lipids clue to unique side group Proteins are made up of 20 different amino acids Simplest amino acid is glycine o A single hydrogen as its side group Amino acids differ in size shape and other characteristics clue to the unique side group o More than half of amino acids are nonessential o the body can synthesize o Takes nitrogen and fragments from CH0 and fat to form amino acids I If 0 Nine amino acids I v 39 39 39 39 M I A are essential I H I body cannot synthesize 0 We must get them from our diets Amino acids are linked together to form proteins Linked together by peptide bonds Condensation reactions connect amino acids Two amino acids bonded together 0 Three amino acids bonded together 0 Multiple amino acids bonded together Most proteins contain a few dozen to hundreds of amino acids group Nonessential Amino Acids Essential Amino Acids OOOO Nutrition 101 Week 6 Proteins amp Lipids 291521115 0 Structure is determined by the sequence of amino acids The 20 amino acids can be linked together in a variety of sequences 0 Determined by weak electrical attractions Positively charged H attract negatively charged 0 Polypeptide chain twists O Long polypeptide chain twists that fold into complex tangled shapes Loss of shape uncoiling of proteins due to heat agitation acid Ex Hardening of an egg when it is cooked or stiffening of egg whites when they are whipped E In the body body proteins denature when exposed to stomach acid Functions of Protein Building blocks of muscles blood and skin Major structural component of all cells 0 Catabolic and anabolic Ex Digestive enzymes 0 Messenger molecules that elicit response to restore normal conditions Ex Insulin amp glucagon O Proteins help to maintain fluid balance Protein can leak into interstitial spaces causing edema O Proteins have negative charges on their surface Attract hydrogen ions with a positive charge Proteins act as buffers O Carry nutrients and molecules in the body s fluids Ex Lipoproteins transport lipids in the body Nutrition 101 Week 6 Proteins amp Lipids 291521115 O Defends the body against disease 0 Proteins are sacrificed during times of starvation or insufficient carb intake 0 Gluconeogenesis Proteins are continuously being broken down and remade Releases amino acids Create an amino acid pool in cells and circulating blood 0 Body does not have enough storage site for extra protein Body breaks down structural and working proteins Amino acids converted to fat in excess Slowed growth impaired brain and kidney functions poor immunity 0 Protein in excess especially animal proteins that are high in saturated fat High intake of red meat that is high in saturated fat Protein intake high 9 calcium excretion increases High protein diets are not good weight management options Important to provide adequate protein for healthy satiety O May accelerate kidney disease but does not cause Protein Recommendations 0 Depends upon protein source Animal protein high QC99 Plant protein lower 7090 0 Soy amp legumes more than 90 0 Contains all essential amino acids Animal products Soy protein Nutrition 101 Week 6 Proteins amp Lipids 291521115 o Complementary Proteins Rice and Beans o AMDR 1035 of calories from protein Translates to 501759 of protein 0 RDA 08 gramskilograms of body weight for adults Pound to kilogram conversion is 22 Divide weight in pounds by 22 to get kilograms 0 Ex 130lbs divided by 22 59 kilograms o Alwais consider the irams of protein as well as the percentage 0 One ounce of protein contains about 7 grams of protein 0 Recommended serving of most animal proteins are 34 ounces 0 What type of protein foods should we eat each week Seafood 20 Meat poultry and eggs 70 Nuts seeds and legumes 10 Milk products are a good source of protein 8 grams per serving Fruits vegetables and grains provide little protein 03g Shopping and Cooking Choose lean sources of protein Trim fat from meats Remove skin before eating 0 Consume protein from food versus supplements Only exception may be competitive athletes o Consume enough protein but not too much OOO Digestion amp Absorption of Proteins O O proteins are crushed and moistened Partial breakdown of protein through hydrolysis Hydrochloric acid uncoils denatures proteins O Polypeptides enter the SI Pancreatic and intestinal proteases hydrolyze them into smaller peptide chains and single amino acids Peptidases on the intestinal wall split most dipeptides and tripeptides into the single amino acids 0 Specific carriers transport amino acids into intestinal cells 0 Once in the cell they may be used for energy or to synthesize needed compounds 0 Amino acids not used by intestinal cells are transported across the cell membrane Then sent to the liver Nutrition 101 Week 6 Proteins amp Lipids 291521115 Lipid Structure fats and oils Most common type of lipid ex lecithin ex cholesterol 0 Lipids have carbon hydrogen and oxygen like carbohydrates Lipids have more calories because they have more carbons and hydrogens o Liiids are characterized by the insolubility to water 0 All fatty acids have the same basic structure 0 Methyl group and an acid group with a chain of carbons and hydrogens in the middle Ta H H T la H l l l i ll l39 I l I HC j j I a 2 5 It I a 2 39 i r 2 C O H ill w H l i 39ll ll l39 l L 4 i H h i i l Length of chain 9 number of carbons Saturation double bonds Location of double bonds Fully loaded with all hydrogen NO double bonds At least one double bond One double bond Ex Oleic acid in olive and canola oil 0 Two or more double bonds Ex Linoleic acid in vegetable oils 4 1 oc ati on of Double bonds Name fatty acids by location of double bond Omega numberposition of double bond closest to the methyl rou CH3 r v I CIOsest dou be b0 nd 3 quot I C 5quot H fkl39it1nquotquotl carbons from methyl group Closest double bond 6 carbons from methyl group Nutrition 101 Week 6 Proteins amp Lipids 291521115 Essential Fatty Acids 0 Cannot be made bi the bodi O Supplied by vegetable oils meats Makes arachidonic acid in Omega6 family Supplied by dark green vegetables vegetable oils and flaxseed Makes eicosapentaenoic acid EPA and docosahexaenoic acid DHA but only in small amounts 0 Food sources include fatty cold water fish shellfish and human milk H 0 i39 1quot H I 0 Contain one glycerol and 3 fatty acids o Condensation forms a triglyceride and Mr hydrolysis breaks it down Characteristics of Fat amp Oils 0 Degree of unsaturation determines firmness o Polyunsaturated fats are liquid at room temperature 0 Animal or saturated fats are solid at room temperature 0 Poliunsaturated fat spoil rancid more easily than saturated fats 0 Some or all points of unsaturation double bonds are saturated by adding hydrogen molecules 0 Prolongs shelf life of food products by preventing oxidation 3 n o Alters texture of foods EMquot 9 H Hydrogenation make liquids more solid 0 Most fats are partially hydrogenated Hydrogenation can cause transfatty acids 39 H I 139 o Phosphate group IS water H C O 13AAAxtxu cxvi H soluble l I H o Lipid component is fat soluble Heck o rN VA W wC 1 H H r CH o Widely known is Lecithin used as an emulsifier in mayo salad I H II O li O C N CH dressmgs and candy bar 0 0H 0 Multiple ring structure EX cholesterol 0 Plant sterols Nutrition 101 Week 6 Proteins amp Lipids 291521115 Similar in structure to cholesterol and can interfere with cholesterol absorption Found in margarine and other functional foods 0 Roles of cholesterol in the body Used to make the active form of Vitamin D Used by the liver to make bile Used to make sterol hormones such as sex hormones adrenal hormones Used in structural component of cell membranes Lipid Digestion amp Absorption 0 Challenge is to keep the lipids mixed vs separation Lipids hydrophobic Digestive enzymes are hydrophilic O Some hard fats melt Muscles contract to propel contents toward pyloric sphincter Lipid particles broken down by gastric lipase When fat enters cholecystokinin CCK is released which signals the release of bile from the gallbladder Bile acts as an emulsifier so the enzymes can act on the fat Most fat digestion occurs in the small intestine Pancreatic lipases and intestinal lipases l a i r 13 o Glycerol amp short and mediumchain fatty acids absorbed directly into the quotWW Protein bloodstream Cholouom 7W Transported by proteins called chylomicrons o Lipid transport is made possible by a group of vehicles known as lipoproteins Largest of the lipoproteins Least dense Nutrition 101 Week 6 Proteins amp Lipids 291521115 0 Get smaller as triglycerides are removed by the cells Composed primarily of triglycerides Transport lipids to the tissues 0 Get smaller and more dense as triglycerides are removed and VLDL becomes LDL Composed primarily of cholesterol with few triglycerides Transport lipids to the tissues Composted primarily of protein 0 Transport cholesterol from the cells to the liver 0 High LDL is associated with higher risk of heart disease and known as bad cholesterol 0 High HDL appears to have a protective effect Functions of Lipids Part of every cell membrane 0 Storage of triglycerides in adipose tissue is unlimited 0 Insulation of body temperature 0 Protection of vital organs 0 In foods lipids function to 0 Give foods flavor and aroma 0 Transport fat soluble vitamins 0 Provide kcalories triglyceride O LDL cholesterol accumulates in arteries until blood flow is slowed or stops Saturated and trans fats appear to be associated with a rise in LDL Recommended lowering saturated fat and trans fats by decreasing animal fats high fat meat choose leaner cooking methods low fat milk Recommended increasing unsaturated fat by increasing olive oil nuts avocados and salmon o May promote cancer growth Evidence not strong Recommended to reduce red meat More fat more calories Nutrition 101 Week 6 Proteins amp Lipids 291521115 Fat Recommendations o AMDR for fat 2035 calories from fat 0 Less than 10 of energy from saturated fat 0 Little to no trans fats o 300mi or less of dietary cholesterol 0 510 of calories from linoleic acid 0 O612 of calories from linoleninc acid What do you think is our actual average percentage of calories from fat 0 Actual intake of Calories from fat on average is 34 Calories from saturated fat is 11 6 grams of trans fats Too much linoleic acid Omega 6 Too little linolenic acid Omega 3 Woman consume 230mg cholesterol Men consume 362mg cholesterol Real Life Recommendations 0 Reduce consumption of animal fats Encourage fat in the form of oils Choose low fat cooking methods broiled baked grilled Emphasize whole grains fruits and vegetables that are low in fat Check the nutrition facts label for fat saturated fat and trans fat Food groups that contain a significant amount of fat are protein milk and milk products and processed grains OOOOO Mk 1 52531 Mews w