Chapter 5 Lipids Fats Phospholipids and Sterols Chapter 5 Learning Objectives Define hydrophobic and hydrophilic 1 2 3 4 5 6 7 8 9 List the 3 categories of lipids Discuss functions of each category of lipids in the body List the number of calories per gram provided by fat and identify the AMDR for fat Compare the structure of fatty acids triglycerides phospholipids and sterols For fatty acids compare the structures of saturated polyunsaturated monounsaturated omega 3 omega 6 and trans fatty acids and be able to identify each structure Identify dietary sources of saturated fats unsaturated fats trans fats and cholesterol Identify the essential fatty acids Define lipoprotein Copyright 2010 John Wiley Sons Inc Chapter 5 Learning Objectives Discuss the steps of digestion and absorption of lipids 10 11 12 13 14 15 16 17 Describe how lipids are transported in the blood and delivered to the cells Compare the functions of LDL vs HDL cholesterol in the body Discuss the relationship between dietary omega 3 and omega 6 fatty acids and health Define atherosclerosis and describe the events that lead to the development of this condition List the risk factors for heart disease Discuss the diet and lifestyle changes that may reduce the risk of developing heart disease differentiating those that improve LDL vs HDL cholesterol Discuss the relationship between dietary fat and cancer and obesity Copyright 2010 John Wiley Sons Inc Chapter 5 Learning Objectives 18 19 20 Use food labels to choose foods containing healthy fats Identify foods that may be high in saturated or trans fats and name an appropriate substitute for that food item Describe the Mediterranean Diet and its impact on health Copyright 2010 John Wiley Sons Inc Lipids Three types or categories of lipids triglycerides phospholipids sterols In food lipids contribute texture taste flavor and enhance the aroma of foods Copyright 2010 John Wiley Sons Inc Lipids Fats and oils contain calories per gram AMDR for fat 9 20 35 of daily calories The typical American diet gets about 33 of its calories from fat within AMDR but Some fats are essential Copyright 2010 John Wiley Sons Inc Categories of Lipids Triglycerides Major form of lipid in food and in the body 3 C molecule Copyright 2010 John Wiley Sons Inc Categories of Lipids Fatty acid characteristics In relation to water Hydrophobic One type of fatty acid differs from another based on 1 2 3 Number of carbons Double or single bonds between carbons Total number of double bonds Copyright 2010 John Wiley Sons Inc Types of Fatty Acids Saturated fatty acid Unsaturated fatty acid monounsaturated fatty acid polyunsaturated fatty acid Omega 6 fatty acid Omega 3 fatty acid Food sources of saturated and unsaturated fatty acids Saturated fatty acids found predominately in animal based foods Also found in palm oil and coconut oil Association with heart disease Unsaturated fatty acids found predominately in plant based foods cooking oils nuts and seeds Copyright 2010 John Wiley Sons Inc Trans Fatty Acids Trans fatty acids can be created by hydrogenation Causes some double bonds to become saturated with hydrogens If hydrogens on same side of carbon chain Cis Configuration If hydrogens on opposite side of carbon chain Trans configuration Improves storage or shelf life of certain products that contain these fats but for health association with increased risk for heart disease Copyright 2010 John Wiley Sons Inc Other sources of trans fats source Blake Nutrition You Pearson Benjamin Cummings Fatty Acid Composition of Foods Copyright 2010 John Wiley Sons Inc Essential Fatty Acids Essential fatty acids Must be acquired in diet Humans unable to create double bond in the omega 3 and omega 6 positions 2 essential fatty acids Linoleic Acid omega 6 or 6 Alpha Linolenic acid omega 3 or 3 Essential Fatty Acids AA Copyright 2010 John Wiley Sons Inc Types of lipids The type of lipid that has a glycerol backbone two fatty acids and a phosphate group is called Phospholipids Ex lecithin Solubility in water Phosphorus containing head Hydrophilic Fatty acid tail Hydrophobic Importance in body Copyright 2010 John Wiley Sons Inc Phospholipids Copyright 2010 John Wiley Sons Inc Phospholipids Copyright 2010 John Wiley Sons Inc Phospholipids acted as emulsifiers Copyright 2010 John Wiley Sons Inc Sterols Sterols are comprised mainly of four connecting rings of carbon and hydrogen Example Cholesterol Important role in cell membrane structure Precursor of important compounds in body Ex hormones bile acid vitamin D Not required in diet since body makes all cholesterol needed Not essential Plant sterols also consumed in diet Cholesterol Copyright 2010 John Wiley Sons Inc Lipid Digestion and Absorption Body composed primarily of water including the gastrointestinal tract Lipids are hydrophobic The digestion and absorption of lipids requires Bile Micelles Chylomicrons Copyright 2010 John Wiley Sons Inc Lipid Digestion Copyright 2010 John Wiley Sons Inc Chylomicron Terms for Lipid Digestion and Absorption Bile Liver Gallbladder Lipase pancreatic some in mouth Micelle Chylomicron Lymphatic system lymph Copyright 2010 John Wiley Sons Inc Lipoproteins in the Body Lipoproteins transport lipid compounds throughout the body Fatty acids cholesterol and other fat soluble vitamins Lipoproteins have water soluble envelope to transport fat soluble nutrients from diet through body The outer layer is composed of Protein Phospholipid Cholesterol Copyright 2010 John Wiley Sons Inc Structure of Lipoprotein Copyright 2010 John Wiley Sons Inc Composition of Lipoproteins Figure 5 12 Lipoproteins in the body Types of lipoproteins Chylomicron contains Dietary fats Very low density lipoprotein VLDL contains primarily Triglycerides Half of low density lipoprotein LDL is Cholesterol bad cholesterol High density lipoprotein HDL good cholesterol Copyright 2010 John Wiley Sons Inc Lipoproteins in blood The function of LDL is to take cholesterol to the cells The function of HDL is takes cholesterol from the cells to the live to create bile 2012 John Wiley Sons Inc All rights reserved Functions of Fat in the body The functions of fat include 1 Energy dense source of fuel 9 kcal gram Cholesterol sterol regulatory and structural role Assists with absorption of fat soluble vitamins Essential part of the cell membranes Cholesterol Phospholipids Insulates body to maintain body temperature Cushions bones organs nerves In foods adds flavor texture aroma 2 3 4 5 6 7