Biology 45 - LipidsAnna Miller, MS, RD 1Biology 45The Lipids• Types Triglycerides Phospholipids Sterols• FunctionsBiology 45Triglycerides (TG)• The fats and oils in foods• The fat on the body• Made up of Glycerol + 3 Fatty AcidsBiology 45Biology 45 - LipidsAnna Miller, MS, RD 2Biology 45Omega-3 and Omega-6 Fatty AcidsBiology 45Essential Fatty Acids• Linoleic acid (O-6) and Linolenic acid (O-3) are essential fatty acids (EFAs)• Lack of them  deficiency• The body uses them to make eicosanoids “Localized hormones” Prostaglandins, thromboxanes, leukotrienesBiology 45Eicosanoids• Those made from Omega 3 fats  Blood pressure  heart rate  blood clotting  immune response  inflammation• Those made from O-6 have the opposite effects• Average American diet has much more O-6 than O-3 – this affects health!Biology 45 - LipidsAnna Miller, MS, RD 3Biology 45Possible Benefits of a Having More O-3 fat in the diet• Reduces risk of heart disease and strokes• Decreases inflammatory response• Helps to prevent mild depression• And maybe more…….Biology 45Dietary Sources• Omega 6 Polyunsaturated vegetable oils (linoleic acid) Some in meat, poultry & eggs (arachidonic acid)• Omega 3 Decosahexanoic Acid (DHA),Eicosapentanoic Acid (EPA)• From Cold water (fatty) fish  Salmon, tuna, herring, mackerel and more Linolenic Acid • From plant sources Flaxseed, Walnuts, Soybeans, Other minor sourcesBiology 45Table H5-1, p. 166Biology 45 - LipidsAnna Miller, MS, RD 4Biology 45Hydrogenation• Processing that adds hydrogen onto a polyunsaturated fatty acid. This makes it more solid and stable• Fully Hydrogenated oil: polyunsaturated fatty acids are converted to saturated fatty acids• Partially Hydrogenated oil: polyunsaturated fatty acids are converted to Trans Fatty Acids• Useful for baking and frying Biology 45Cis- and Trans-Fatty Acids ComparedBiology 45Health Effects of Trans Fats• the “bad” cholesterol in the blood•  the “good” cholesterol in the blood• Other detrimental health effects?Biology 45 - LipidsAnna Miller, MS, RD 5Biology 45Foods High in Trans Fats• Shortening• Standard Margarine (not butter!)• Foods made with Partially hydrogenated Oil Some cookies, cakes  Some Fried Foods Other foods with added fatBiology 45Questions!• Which is better to use: Butter or Margarine?• Is a food healthy if it says “Contains No Trans Fat” on the label?Biology 45Phospholipids• Read on your own• Use the study guide• Not much to learn about these!Biology 45 - LipidsAnna Miller, MS, RD 6Biology 45SterolsBiology 45Cholesterol is found only in animal foods Dietary CholesterolCopyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson LearningBiology 45Fat DigestionWhat are the end products of the digestion of TG?Biology 45 - LipidsAnna Miller, MS, RD 7Biology 45Fig. 5-17, p. 145Biology 45Lipid Transport• Lipoproteins Packages that transport lipids in the blood Why are they needed?Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson LearningBiology 45Biology 45 - LipidsAnna Miller, MS, RD 8Biology 45Lipoproteins and Health• LDL (Low Density Lipoprotein)“Bad” Cholesterol Delivers cholesterol to cells (that’s “good”!) Can contribute to clogging of arteries Ideal if it is low• HDL(High Density Lipoprotein)“Good” Cholesterol Removes cholesterol from dying cells and from artery walls Helps to clear arteries Ideal if it is high• Not in foods – in blood only!Biology 45Storing and Using Fat• Adipose tissue Lipoprotein lipase (LPL)•Enzyme that hydrolyzes TG for the purpose of taking up the TG into the cell Hormone sensitive lipase (HSL)•Enzyme in fat cells that hydrolyzes TG for the purpose of allowing fat to leave when fat is needed as a fuelBiology 45• There is no RDA for fat• AMDR = 20% - 35% of calories (~45 – 80 g fat/day)• Quality vs quantityHow Much Fat Should I Eat?Biology 45 - LipidsAnna Miller, MS, RD 9Biology 45Healthy FatsMonounsaturated and omega 3 fatsBiology 45Not-so-healthy Fats• Saturated fat• Trans fatBiology 45Do This at Home• Classify the Fats on the menu in the handout (“Carbohydrate and Fat Worksheet”) in the packet. Do this before you check the answers on my website!Biology 45 - LipidsAnna Miller, MS, RD 10Biology 45Table H5-2, p. 168Biology 45Real Life Task!• Try to replace less-healthy-fats with healthier ones in YOUR diet Avocado instead of cheese Bread dipped in olive oil/balsamic vinegar instead of butter Nuts as a snack Guacamole with chips instead of nachos Olive oil salad dressing instead of cheesy dressing Fish taco instead of beef tacos Saute in olive or canola oil instead of butter or margarineBiology 45Eat Healthy Fats Every Day / Every Meal!• Use olive or canola oil Cooking, baking Salad dressings• Snack on nuts• Enjoy avocados• Have fish 3-4 times a weekCopyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson