Chapter 6 Lipids Lipids aka Fats Contain C H O Contain much more C H than O Do not readily dissolve in water Our digestive juices and blood are based Give a creamy mouth feel adds flavor Essential fats for health Not all fats are created equally Fats lipids solid at room temp and oils lipids liquid at room temp Provide 9 kcals gm Lipid Family Triglycerides Fatty acids Most common type of lipid in our food and body 95 of fats we eat 95 of fat stored Monoglyceride Diglyceride Triglycerides Structure 3 fatty acids attached to a glycerol backbone or different Monoglycerides acids Diglycerides loses 2 fatty loses a fatty acid Changing the Structure of a Triglyceride Esterification Process of attaching a fatty acid to glycerol One water molecule is formed with each ester bond De esterification Removal of a fatty acid from glycerol Free fatty acid Uses a water molecule to break off Re esterification Reattaching a fatty acid to glycerol that has lost a fatty acid Ester bonds Free Fatty Acids FFAs Methyl group CH3 at one end end Carboxyl group COOH at the other end end FFAs differ by Number of Carbons H saturation shape of chain straight or bent Carbon Chain Length Long chain fatty acids LCFA 12 or more carbon atoms Transported via lymphatic system Fats from beef pork and lamb Medium chain fatty acids MCFA 6 to 10 carbons Transported via circulatory system Coconut and palm kernel oils Short chain fatty acids SCFA Less than 6 carbons Transported via circulatory system Fat in dairy products butter whole Saturation of Fatty Acids FAs Saturated fatty acid 0 double bonds Monounsaturated fatty acid 1 double bond Polyunsaturated fatty acid More than 2 double bonds Shape of Fatty Acids Unsaturated cis fatty acid H attached to double bond are on the same sides or carbon chains Occur naturally All the fatty acids can be the same milk Regulates BP and increases phosphate group Saturated trans fatty acid H attached to double bond are on carbon opposite sides chains creates form What is that Naming Fatty Acids Omega System Indicates where the first double bond closest to the methyl end occurs Delta System Uses the carboxyl end and indicates where all the double bonds occur Essential Fatty Acids EFAs PUFAs Linolenic acid An omega 6 fatty acid Eicosanoids clotting Alpha linolenic acid An omega 3 fatty acid Eicosanoids Dihomo gamma linolenic acid arachidonic acid Food Sources of Triglycerides Animal fats Vegetable oils Diary products Low fat products are available Grains Naturally low in fat except when fat is added e g pastries pancakes Fruits and Vegetables Naturally low in fat except coconut and avocados Functions of Triglycerides Provide energy Main energy source for all body cells except nervous system and RBC 9 kcals gm Provide compact energy storage stable and calorie dense Nearly limitless storage Insulation Protection Subcutaneous and visceral fat Subcutaneous helps keep body at a normal temperature Visceral helps the organs from getting jostled around Aid in Fat soluble vitamin absorption transport Vitamins A D E K Essential fatty acid functions Eicosanoids have over 100 different actions Phospholipids Lipid consisting of a head tail Hydrophilic head Hydrophobic tail 2 main functions Component of cell membrane emulsifier Sources Synthesized Food Sterols Carbons arranged in many rings Most well known sterol is cholesterol Functions make testosterone and estrogen vitamin D bile Sources Synthesized by our bodies Foods Plants are sources of other sterols Can reduce absorption of cholesterol and bile risk of CVD Recommended Fat Intake No RDA AMDR 20 35 of total calories Saturated Trans Cholesterol as low as possible Omega 6 5 Omega 3 0 6 1 2 Mediterranean Diet Up to 40 of calories from fat Diet is rich in Olive oils fruits vegetables whole grains beans nuts and seeds Diet has small intakes of Cheese yogurt wine with meals and fish weekly intake Diet limited Red meat and eggs Regular exercise Intake has doubled in the last century Our Fat Intake Omega 6s is plentiful Omega 3s is low Food sources cold water fish walnuts flax seeds canola Supplements 650 mg EPA DHA Caution Prolonged bleeding Fat Digestion Mouth lipase and chained TGs Stomach lipase TGs Small Intestine Presence of fat triggers Hormone from intestinal cells Hormone stimulates release from gallbladder and from pancreas Bile emulsified fat into tiny droplets called Bile forms a shell are acted upon by pancreatic lipase to break into and Colipase assists pancreatic lipase in attaching Fat Digestion in the Small Intestine TGs are broken down into By pancreatic are broken down into FFAs glycerol phosphoric acid other components e g choline By pancreatic enzymes and SI enzymes esters are broken down to By pancreatic Fat Absorption Micelles absorbed in the and of the SI FAs are absorbed via the portal vein which leads to Then FAs are packaged into enter the lymphatic system Bile is recycles via enterohepatic circulation in the pathway remove LDLs can build up Figure Absorption of TGs Figure Overview of Lipid Digestion and Absorption Transporting Fat in the Blood Fat is transported as What is it made up of Types Table Composition and Roles Figure Lipoprotein Interactions Transferring TGs into Body Cells The enzyme lipase sits on the surface of cells Blood vessels muscles fat adipose tissue etc LPL transfers TGs for energy use or storage tend to use tend to store Lipid storage in adipose LPL breaks down TG into and Both enter adipose cell and are into Pathways for Cholesterol Uptake Pathway LDL take up by broken down and components are Excess in blood becomes in these cells and them Overtime the filled scavengers build up on the inter blood vessel walls This results in High Density Lipoprotein HDL Produced by and Picks up throughout body From cells or other sources Donates to other lipoproteins Transported back to the Some HDL goes back to the the oxidation of LDL Ways to Reverse Plaque Buildup Daily exercise to strengthen heart and improve blood circulation 20 minutes of walking slow jogging or bicycling Lay off foods Especially fats No more than 35 of total caloric intake from any fat Eat no more than 200 mg of unsaturated 20 total calories 200mg day Include 2gm plant sterols day 20 30gm day of fiber Moderate intake Maintain a healthy body weight physical activity Stop s and drinking excessive amounts of Surgery angioplasty Medication statins Health Concerns Related to Fat Intake High fat Raises cholesterol deposited in arteries Excessive