Chapter 6: Lipids
Chapter 6: Lipids HUMNNTR 2310 - 0010
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This 10 page Class Notes was uploaded by Victoria Gonzalez on Tuesday October 13, 2015. The Class Notes belongs to HUMNNTR 2310 - 0010 at Ohio State University taught by Irene Hatsu in Fall 2015. Since its upload, it has received 21 views. For similar materials see Fundamentals of Nutrition in Human Development at Ohio State University.
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Date Created: 10/13/15
Chapter 6 Lipids Victoria Gonzalez 1 Lipids a Fats and oils i Fats are solid at room temperature ii Oils are liquid at room temperature b All contain carbon hydrogen and oxygen c None can dissolve in water 2 Types of lipids a Triglycerides 95 of lipids in foods and bodies b Phospholipids c Sterols 3 Structure of fats a Triglyceride glycerol and 3 fatty acids i Glycerol small 3carbon carbohydrate ii Fatty acid chain of carbons with hydrogen atoms iii Mix of 2 or 3 types of fatty acids usually iv Glycerol and fatty acids are joined by ester bonds b Esteri cation the process of attaching fatty acids to glycerol releases water c Hydrolysis the release of fatty acids from glycerol 4 Fatty acids differ in three ways a Chain length i Long 12 or more carbons ii Medium 6 10 carbons iii Short less than 6 carbons 1 Shorter chain are more quickly digested b Degree of saturation i Saturated lled with hydrogen bonds 1 Solid at room temperature 2 Animal fats butter lard 3 Some plant oils palm oil coconut oil shortening crisco ii Unsaturated some hydrogen is missing causing double bonds 1 Liquid at room temperature 2 Likely to spoil oxidize 3 Most plant oils 4 Monounsaturated MUFA unsaturated at one point one double bond 5 Polyunsaturated PUFA unsaturated at 2 or more points 2 or more double bonds c Chain shape i Straight carbon chain saturated and trans fats ii Bent carbon chain unsaturated and cis fats 5 Hydrogenated oils a Hydrogenate make unsaturated fatty acids more saturated by adding hydrogen to carbon chains i How oils become solid fats b Easy to handle and store prevent spoilagerancidity c High smoking point good for frying d To improve texture of foods 6 Partially hydrogenated oils produces trans fatty acids a Health dangers of excessive trans fats from hydrogenation b Increases risk for heart disease i For every 2 rise in kcal from trans fat risk of coronary heart disease rises 23 c Now on food labels January 2006 i Changing recipesformulations ii More fully hydrogenated oils saturated fats 7 Cis and trans fats a Cis fats hydrogen is on the same side causing the backbone of the molecule to bend i Behaves like an unsaturated fat b Trans fats hydrogen is on opposite sides of double bond i Behaves more like a saturated fat Hydrogen Eh farm causes tam littlehe Elf moleculew 7 beml Tram farm Dleii infill Ellauidli acid 8 Essential fatty acids body cannot make them a Two PUFAs i Omega3 alphalinolenic acid ALA rst double bond is after carbon 3 1 Omega3 is used to make EPA and DHA 2 Sources a Plants ALA i Flaxseed and oil ii Canola oil iii Soybean oi b Marine EPA and DHA i Salmon ii Tuna iii Trout iv Shrimp c Algae seaweed is a plant source of EPA amp DHA d Omega3 fats is high in eskimo diets i Low rates of heart attacks ii EPA and DHA from marine sources iii Lower blood triglycerides iv Decreased clotting atherosclerosis v EPA and DHA is associated with many health bene ts sh oil ii Omega6 Iinoleic aid LA rst double bond is after carbon 6 1 Sources of omega6 fats a Plants Iinoleic acids i Sun ower oil and seeds ii Corn oil HL Soybeans iv Pecans b Animal archidonic acid i Meats ii Poultry iH Eggs b Essential fatty acids are used to make other important fatty acids Fatigunjgl miled PalPI Mist Alphiaialiriul nic acid b Lihnleiic acid if i t quot ri 711 DIhDM39QQMI MU HWHE IE EIGI dJ V quot I if quot7 iiiquoti a 3 l EisanEn lnmanuicpci l lil Bacosahamemoic acid DHHF 117 r IF fifi mchidani mid j 77 395 lEll S l r ildi l quot134 9 Health concerns related to PUFA intake a High omega6 fatty acid intake i More than 10 kcal may increase cholesterol plaques b Excessive omega3 fatty acid intake i May impair immunity ii May increase risk of hemorrhagic stroke c Imbalances in omega3 and omega6 fatty acid intake i Keep n6 at 510 kcal ii Increase n3s d Intake of rancid fats i Use air tight packages ii Add antioxidants Vitamin C amp E 10 Phospholipid a Glycerol 2 fatty acids and a phosphorous compound i Phosphate group replaces a fatty acid b Synthesized by body Found widely in food FuncUons i Make up cell membrane ii Emulsi er suspend fat droplets to mix with water 1 Bile 2 Lecithin found in peanuts and egg yolk 3 Improves food products e Phospholipids surround fat i Hydrophilic heads face away from fat ii Hydrophobic tails point towards fat 11 Sterols multiringed structure Waxy substances do not dissolve in water Ex cholesterol L FuncUons 1 Used to make bie 2 Makes vitamin D activated by sunlight 3 Makes brain and nerve cells 4 Makes sex steroid hormones estrogen and testosterone ii Found in all cell membranes iii Allows for transport of lipids iv Cholesterol is not an essential nutrient 1 Liver makes 900 mgday an 79 2 Excess cholesterol is deposited in arteries and can cause heart attacks and strokes v Part of atherosclerotic plaques vi Blood cholesterol 1 Predictor of heart disease 2 Ratio of good to quotbadquot cholesterol is important vii Cholesterol sources 1 In animal products a Liver b Eggs yolk principal source of cholesterol c Beef d Whole milk e Skim milk 12 Recommended fat intakes for adults a 2035 dietary fat i 2100 calorie diet 4770 grams ii 2400 calorie diet 5380 grams b Omega6 510 of calories Omega3 0612 of calories Omega3 and Omega6 quantities are not on food labels 13 Techniques to reduce fat intake a Reducedfat foods i Total energy is the same as normal food ii Sugar is usually added in the place of fat especially in dessert items b Fat substitutes i Can be lower in energy ii What is added in the place of fat Water diet margarine Starch derivatives Fiber cellulose Protein globules from whey protein Arti cial fat olestra a Olestra sucrose polyester i Fatty acids linked to sucrose ii Looks feels tastes like fat iii lndigestible iv Trade name Olean v Used in snack foods potato chips an U39lbUUNl l 14 Fat digestion a Mouth i Lingual lipase 1 Works on short fatty acids milk ii Breakdown of T6 with short and medium chained fatty acids in milk fat iii Adulthood little to no fat digestion b Stomach i Small amount fat digested ii Gastric lipase acts on triglycerides with short and medium chained fatty acids iii Long chained fatty acids are not affected by the stomach c Small intestine i Primary site for fat digestion ii Cholecystokinin stimulates the release of 1 Lipase form the pancreas 2 Bile from the gall bladder iii Triglycerides 1 Emulsi ed by bile 2 Separated into tiny particles micelles 3 Digested into monoglycerides and fatty acids a By lipase from the pancreas 15 Fat absorption Products of fat digestion fatty acids and monoglycerides Absorbed into small intestine cells c Fatty acids i Short or medium chain less than 12 carbons 1 Water soluble 2 Enter the portal vein ii Long chain 12 or more carbons 1 Reformed into triglycerides 2 Packaged into chylomicrons 3 Enter lymphatic system 4 About 95 of fat is consumed in absorbed 16 Transport of fats in the blood a Blood is waterbased fat is oilbased b A unique system of fat transport is needed c Lipoproteins fat packages 79 Compounds in bloodstream iI iii Shell of phospholipids protein cholesterol Core of lipids Types of lipoproteins 1 Chylomicrons Largest lipoprotein Contains triglycerides from diet Enter lymphatic system Travel through blood Fatty acids are absorbed by cells muscle adipose f With help of lipoprotein lipase 2 Very lowdensity lipoprotein VLDL a Made by liver b Contains triglycerides and cholesterol c Become LDL when lose triglycerides 3 Lowdensity lipoproteins LDL a Takes cholesterol to cells by normal receptor pathway b Excess LDL in blood i Taken up by macrophages scavenger cells in blood vessels 1 Scavenger pathway a Scavenger WBC remove LDL from circulation b Prevents oxidized LDL form returning to circulation EDPOFT c Die and buildup as plaque on walls of the blood vessels d Leads to atherosclerosis e High density lipoproteins pick up cholesterol throughout the body 2 Especially oxidized LDL c High blood LDL associated with i High blood cholesterol ii High heart attack risk d Normal LDL receptor pathway i LDLs are taken up by cells broken down and components utilized ii Excess in blood becomes oxidized 17 18 4 High density lipoproteins HDL quotGood cholesterolquot More protein higher density Heaviest lipoprotein Takes cholesterol to liver for excretion High HDL associated with lower blood cholesterol lower heart attack rish How do we raise HDL i Most in uential factor physical activity 1 At least 45 minutesday 4 days a week ii Avoid smoking iii Eat regular meals vs constant grazing iv Eat less total fat less than 30 of calories v Moderate intake of alcohol Diet and heart disease D9059 h Cardiovascular disease disease of heart and blood vessels Atherosclerosis plaque on artery walls i Plaque cholesterol LDL protein smooth muscle calcium ii Arteries harden and narrow blood pressure increases Coronary heart disease CHD i Coronary arteries are affected ii Stroke Others peripheral artery disease aortic disease Risk factors for heart disease Can change Blood cholesterol ii LDL iii Blood triglycerides iv HDL v Smoking vi High blood pressure vii Obesity physical inactivity diabetes Can t change i Age men over 45 women over 55 ii Genetics iH Race iv Gender 10 19 American heart association dietary recommendations Total fat intake 2035 of calories i Current US diet 33 of total kcal from fat 1 A lot from animals whole milk pastries cheese margarine and mayonnaise Reduce saturated fat less than 7 of calories i Replace with 1 Monosaturated fat olive oil avocados 2 Monosaturated fat in LDLs are less likely to be oxidized 3 Polyunsaturated fat maintain omega6 and omega3 balance Reduce cholesterol less than 300 mgday
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