Chapter 4 Fats or Lipids Macronutrient category Lipids The Lipids in our Food and our Bodies Fats or lipids are defined as substances that are insoluble in water but soluble in organic solvents Ether acetone chloroform List the categories of lipids A wide variety of lipids influence human health Triglycerides Phospholipids Sterols Ex cholesterol Lipids are composed of the same elements that are contained in carbohydrates Carbon Hydrogen Oxygen Discuss why lipids have more energy than carbohydrates The major difference is that lipids contain almost twice as many hydrogen atoms than do carbohydrates when metabolized more energy is yielded Fatty Acids Discuss the structure of fatty acids Fatty acids are simply a chain of carbons linked bonded together The chain has a carboxyl group on one end and a methyl group on the other Carboxyl group COOH Hydrophilic characteristic attracted to water Methyl group CH3 Hydrophobic does not mix with water Fatty acids are not only important lipid compounds by themselves but also as components of triglycerides and phospholipids Fatty Acid Saturation Each carbon may have up to two hydrogen s attached Fatty acid saturation whether a fatty acid carbon chain is occupied by all of the hydrogen atoms it can hold Refers to the amount of hydrogen that are attached to each of the carbon in that fatty acid If the chain is fully occupied by hydrogen atoms then it is a Saturated fatty acid water When hydrogen atoms are missing a double bond forms between carbons Unsaturated fatty acid missing a hydrogen at least one double bond A fatty acid with one double bond is called Monounsaturated fatty acid Two or more double bonds Polyunsaturated fatty acids Fatty Acids Differences between saturated monounsaturated polysaturated fatty acids Saturated fatty acid Compare the effects of saturation on the state of the fatty acid at room temperature More solid at room temperature ex butter Monounsaturated fatty acid One double bond Tends to stay a liquid at room temperature Polyunsaturated fatty acid Liquid at room temperature Fatty Acids in Common Foods Nutrition Page 1 Fatty Acids in Common Foods Essential and Nonessential Fatty Acids Fatty acids that cannot be made by the body provided Essential fatty acids Must be provided in the diet IDENTIFY TWO ESSENTIAL FATTY ACIDS REFERRING TO There are 2 families of fatty acids Omega 6 Considered to be essential fatty acid is Linoleic acids Omega 3 Linolenic acid Omega 3 and Omega 6 Fatty Acids The numbers 3 and 6 refer to where the double bonds are located in the fatty acids The location of the double bonds drastically affects the function of the fatty acid Discuss the effects of omega 6 and omega 3 fatty acid products in the body and on health Omega 6 fatty acids are incorporated into cell membranes and are precursors to powerful biological compounds that can play a role in reproduction and blood flow Arachadonic acid metabolic end products affect blood pressure blood flow Omega 3 fatty acids are also found in cell membranes and help prevent tissue inflammation Eicosapentaenoic acid EPA good source is fish Docosahexaenoic acid DHA May reduce Heart disease Likelihood of formations of blood clots Most Americans get plenty of omega 6 fatty acids but not enough omega 3 Identify the two essential fatty acids and common dietary sources of each Nutrition Page 2 Identify the two essential fatty acids and common dietary sources of each Trans Fatty Acids Define hydrogenation Hydrogenation Process of adding hydrogens back to unsaturated fat Makes liquid fat a solid Increases shelf life Commonly found in store bought cakes cookies crackers other snack foods Margarine and shortening other common sources A fatty acid produced through addition of hydrogen atoms to double bonds of fatty acids that causes the molecule to assume an unnatural shape Trans fatty acid Only a small amount of naturally occurring trans fatty acids are found in Milk and meat Trans Fatty Acids Differences between cis trans fatty acids Cis vs Trans fatty acids Cis fall on the same side maintains the bent structure Trans fall on opposite sides Hydrogen lands on north and south straightens out the fatty acid When only some unsaturated fats are converted to saturated fats via hydrogenation Partially hydrogenated little trans fat present Margarine form of hydrogenated fat More hydrogenated more trans fat Trans Fatty Acids Dietary trans fatty acids from hydrogenation are associated with Increased levels of bad cholesterol or lower density lipoprotein LDL May lower good or high intensity lipoprotein Increased risk for heart disease When have high low density lipoprotein and or low amounts of HDL increased risk for heart disease When LDL elevated and or HDL is low Can be exaggerated by eating trans fat The American Heart Association recommends 2 g of trans fatty acids per day or less Less than 1 of calories Triglycerides Triglyceride a chemical structure composed of A 3 carbon glycerol backbone 3 fatty acids are bonded to each of the carbons glycerol backbone Hydrophobic don t mix well with water Primary form of lipid fat found in food and in the body eating fat triglycerides The fatty acids in triglycerides found in the body often reflect dietary fatty acids consumed if eating more mono poly triglycerides will appear the same Phospholipids Phospholipids are a compound that helps your body with the task of transporting fat through watery substance Chemically similar to triglycerides Nutrition Page 3 Chemically similar to triglycerides 3 carbon glycerol backbone 2 fatty acids bound to first two carbons Third carbon has phosphate group bound to it The presence of this phosphate group changes the physical properties of the structure Phosphate head is hydrophilic Fatty acid tail is hydrophobic Phospholipid has hydrophilic and hydrophobic quality in one unit Phospholipids are uniquely suited to function as emulsifier Blending of fat and water Emulsifier will circle towards the edge phosphate head will be exposed to the water so fat stays dispersed In the body phospholipids are important as part of Cell membrane Lipoproteins Transport particles for fats in the body Sterols Cholesterol These groups of lipids are quite different chemically from the other lipids Four rings Includes cholesterol form of sterols Sterols are vital to health and basic metabolic functions Examples of sterols Testosterone Estrogen Vitamin D Sterols Cholesterol The liver makes most of the cholesterol our bodies