The Lipids Triglycerides Phospholipids Sterols Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipids Triglycerides –Fats and oils Phospholipids Sterols Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fatty Acids and Triglycerides Copyright 2005 Wadsworth Group, a division of Thomson Learning glycerol

Fatty Acids and Triglycerides glycerol + 3 fatty acids  triglyceride + H 2 O Copyright 2005 Wadsworth Group, a division of Thomson Learning

Condensation of Glycerol & Fatty Acids to Form a Triglyceride

Fatty Acids Fatty acids –Length –Saturated vs. unsaturated Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fatty Acids Organic acids –Example: acetic acid Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fatty Acids Length of carbon chain Copyright 2005 Wadsworth Group, a division of Thomson Learning Stearic acid – 18-carbon, saturated Simplified structure

Fatty Acids Point of unsaturation Degree of unsaturation –Saturated fatty acid –Monounsaturated fatty acid –Polyunsaturated fatty acid Copyright 2005 Wadsworth Group, a division of Thomson Learning

An impossible chemical structure Oleic acid – 18-carbon, monounsaturated Linoleic acid – 18-carbon, polyunsaturated

Fatty Acids Location of double bonds –Omega number Omega-3 fatty acid Omega-6 fatty acid Copyright 2005 Wadsworth Group, a division of Thomson Learning

Omega-3 and Omega-6 Fatty Acids Compared

Triglycerides Degree of unsaturation revisited –Firmness –Stability Oxidation –Antioxidants Copyright 2005 Wadsworth Group, a division of Thomson Learning

Triglycerides Degree of unsaturation revisited –Hydrogenation –Cis vs. trans-fatty acids Copyright 2005 Wadsworth Group, a division of Thomson Learning

Hydrogenation

Copyright 2005 Wadsworth Group, a division of Thomson Learning Cis- and Trans-Fatty Acids Compared

Phospholipids Copyright 2005 Wadsworth Group, a division of Thomson Learning

Phospholipids Phospholipids in foods –Lecithin in eggs, soy, wheat germ, peanuts Roles of phospholipids –Plasma membrane –Emulsifiers Copyright 2005 Wadsworth Group, a division of Thomson Learning

Phospholipids Copyright 2005 Wadsworth Group, a division of Thomson Learning

Sterols Copyright 2005 Wadsworth Group, a division of Thomson Learning

Sterols Sterols in foods –Cholesterol only in animal products –Phytosterols in plants Copyright 2005 Wadsworth Group, a division of Thomson Learning

Sterols Roles of sterols –Bile acids –Sex hormones –Adrenal hormones –Vitamin D Copyright 2005 Wadsworth Group, a division of Thomson Learning

Sterols Cholesterol and atherosclerosis Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipids Hydrophobic vs. hydrophilic Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Hydrolysis –Triglycerides  monoglycerides, fatty acids, glycerol Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Mouth –Melting –Lingual lipase Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Stomach –Churning and mixing –Gastric lipase Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Small intestine –CCK Bile and emulsification Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Small intestine –Pancreatic lipases –Intestinal lipases Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Overview Copyright 2005 Wadsworth Group, a division of Thomson Learning

Fat Digestion Enterohepatic circulation Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipid Transport Lipoproteins –Chylomicrons –VLDL = very-low-density lipoproteins –LDL = low-density lipoproteins –HDL = high-density lipoproteins Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipid Transport

Lipoproteins and health –LDL vs. HDL Copyright 2005 Wadsworth Group, a division of Thomson Learning

Roles of Triglycerides Fat stores –Energy –Protection –insulation Copyright 2005 Wadsworth Group, a division of Thomson Learning

Essential Fatty Acids Linoleic acid and the omega-6 family –Arachidonic acid Copyright 2005 Wadsworth Group, a division of Thomson Learning

Essential Fatty Acids Copyright 2005 Wadsworth Group, a division of Thomson Learning

Essential Fatty Acids Linolenic acid and the omega-3 family –EPA =eicosapentaenoic acid –DHA = docosahexaenoic acid Copyright 2005 Wadsworth Group, a division of Thomson Learning

Essential Fatty Acids Eicosanoids –EPA derived vs. arachidonic acid derived Fatty acid deficiencies Copyright 2005 Wadsworth Group, a division of Thomson Learning

Essential Fatty Acids Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipid Metabolism Storage as fat –Adipose tissue –LPL = lipoprotein lipase Copyright 2005 Wadsworth Group, a division of Thomson Learning

Lipid Metabolism Using fat for energy –Hormone- sensitive lipase –Provides very little glucose Copyright 2005 Wadsworth Group, a division of Thomson Learning

Health Effects of Lipids Blood lipid profile Heart disease Risks from saturated fats Copyright 2005 Wadsworth Group, a division of Thomson Learning

Health Effects of Lipids

Risks from trans fats Risks from cholesterol Copyright 2005 Wadsworth Group, a division of Thomson Learning

Dietary Cholesterol Copyright 2005 Wadsworth Group, a division of Thomson Learning

Health Effects of Lipids Benefits from monounsaturated fats and polyunsaturated fats Copyright 2005 Wadsworth Group, a division of Thomson Learning

Health Effects of Lipids Benefits from omega-3 fats Balance omega-6 and omega-3 intakes Copyright 2005 Wadsworth Group, a division of Thomson Learning

Health Effects of Lipids Cancer Obesity Copyright 2005 Wadsworth Group, a division of Thomson Learning

Recommended Intakes of Fat DRI: 20% - 35% of energy intake Copyright 2005 Wadsworth Group, a division of Thomson Learning

Recommended Intakes of Fat Linoleic acid AI –5% - 10% of energy intake –Men 17 g/d; women 12 g/d Linolenic acid AI – % of energy intake –Men 1.6 g/d; women 1.1 g/d Copyright 2005 Wadsworth Group, a division of Thomson Learning

Guidelines to Groceries Meats and meat alternatives Copyright 2005 Wadsworth Group, a division of Thomson Learning

Cutting Fat Cuts kCalories and Saturated Fat Copyright 2005 Wadsworth Group, a division of Thomson Learning

Guidelines to Groceries Milk and milk products Vegetables, fruits, and grains Invisible fat Copyright 2005 Wadsworth Group, a division of Thomson Learning

Guidelines to Groceries Fat replacers –Artificial fats Olestra Copyright 2005 Wadsworth Group, a division of Thomson Learning

High-Fat Foods Changing guidelines for fat intake Copyright 2005 Wadsworth Group, a division of Thomson Learning

High-Fat Foods Cook with olive oil Nibble on nuts Feast on fish –But beware of mercury Copyright 2005 Wadsworth Group, a division of Thomson Learning

High-Fat Foods Limit fatty meats, milk products, and tropical oils Copyright 2005 Wadsworth Group, a division of Thomson Learning

High-Fat Foods Limit hydrogenated foods Copyright 2005 Wadsworth Group, a division of Thomson Learning

High-Fat Foods Mediterranean diet Copyright 2005 Wadsworth Group, a division of Thomson Learning