1. Lipids Triglycerides –Fats and oils Phospholipids –Lecithin Sterols –Cholesterol

2. Objectives After reading Chapter 4, class discussion and case study work, you will be able to –Describe the role of lipids in the body –Identify food sources of fats –Discuss lipid digestion, absorption and transport –Calculate calories from fat

3. Objectives Identify types (classification) of lipids Discuss the health related effects of lipids –Blood lipid profile –Omega fatty acids –Trans fatty acids –Hydrogenation

4. 4 Triglycerides

5. glycerol

6. Triglycerides glycerol + 3 fatty acids  triglyceride

7. Fatty Acids Length of fatty acid –18-24 carbons in length Degree of Saturation –Saturated fatty-acid –Monounsaturated fatty-acid –Polyunsaturated fatty-acid

8. Fatty Acids Point of unsaturation Location of double bonds –Omega number Omega-3 fatty acid Omega-6 fatty acid

9. Triglycerides Degree of saturation determines: –Firmness –Stability Oxidation –Antioxidants

10. Rancidity Definition: Deterioration of fat; resulting in undesirable flavor/odor –Flavor Reversion-soy oil; Cu, Fe Hydrolytic: Separation of glycerol from fatty acids –Short chain fatty acids –Butyric fatty acid; butter Oxidative: Loss of hydrogen in presence of air/heat –Oxidation of double bonds –Polyunsaturated fatty acids

11. Trans Fats Degree of unsaturation revisited –Hydrogenation –Cis vs. trans-fatty acids Trans fat occurs naturally in meat and dairy foods –Conjugated linoleic in milk »Possibly positive for heart health

12. p. 108 NRAEF

13. Phospholipids

14. Phospholipids in foods-Lecithin Roles of phospholipids –Plasma membrane –Emulsifiers

15. Phospholipids

16. Sterols Found in plants and animals Cholesterol is most abundant Found in animals only Found in every cell in man’s body Body makes ~700mg/day Dietary intake 200- 400mg/day

17. Dietary Cholesterol

18. Sterols Roles of sterols –Manufacture bile acids –Make hormones Estrogen and testosterone –Make adrenal hormones –Make Vitamin D –Maintain cell membranes

19. Fat Digestion Hydrolysis –Triglycerides  monoglycerides, fatty acids, glycerol

20. Fat Digestion Mouth –Melting –Lingual Lipase Stomach –Churning and mixing –Gastric Lipase

21. Fat Digestion Small intestine –Fat triggers the release of hormone Cholecystokinin (CCK) –Gallbladder releases bile –Bile emulsifies fat so it can be more fully digested Pancreatic lipase Intestinal lipase

22. Fat Digestion

23. Enterohepatic circulation How bile travels through the body

24. Fat Digestion Overview

25. p.152 5-17

26. Lipid Transport Lipoproteins –Chylomicrons –VLDL = very-low-density lipoproteins –LDL = low-density lipoproteins –HDL = high-density lipoproteins

27. Lipid Transport

28. Lipoproteins and health –LDL: carries cholesterol from liver to the cells of the body High=Less healthy –HDL: carries cholesterol from the cells back to the liver High=More healthy

29. Roles of Triglycerides Fat stores –Energy –Protection –Insulation Provide essential fatty acids

30. Essential Fatty Acids Linoleic acid and the omega-6 family –Arachidonic acid Linolenic acid and the omega-3 family –Alpha omega 3 fatty acids –Marine omega 3 fatty acid EPA =eicosapentaenoic acid DHA = docosahexaenoic acid

31. Essential Fatty Acids

34. Health Effects of Lipids Blood lipid profile –Cholesterol=<200mg/dL –LDL=<100 –HDL=>60 –TG=<150 Risks from saturated fats, trans fats, cholesterol Benefits from polyunsaturated fats monosaturated, omega-3

35. Health Effects of Lipids Risks from trans fats –Alter blood cholesterol like saturated fats –Raise LDL cholesterol –Lower HDL cholesterol at high intakes –Increase inflammation & insulin resistance –AI = 5 gm/day Risks from cholesterol –Not as implicated as saturated or trans fats –Beware cholesterol sensitivity Limit intake <300 mg/day

36. Health Effects of Lipids Benefits from monounsaturated fats and polyunsaturated fats –Olive oil (monounsaturated) Lowers LDL and total cholesterol Lowers blood clotting factors Lowers blood pressure Provides phytochemicals which act as antioxidants

37. Health Effects of Lipids Benefits from omega-3 fats –Prevent arrhythmias –Lower blood pressure –Improve blood vessel function –May ease inflammation –Prevent repeat heart attack 1 gm supplement daily for 3 years Balance omega-6 and omega-3 intakes

38. Recommended Intakes of Fat DRI: 20-35% of energy intake Cholesterol: 200-300 mg/day Linoleic acid AI –5% - 10% of energy intake Linolenic acid AI –0.6 - 1.2% of energy intake

39. Guidelines to Groceries Limit whole milk and milk products Use vegetables, fruits, and grains Avoid invisible fat Avoid tropical oils Use low fat meats and Alternatives

40. Fat Distribution in Diet

41. p. 162 Fig 5-23

44. Beware the Label “0 Trans Fat” – can still contain up to 0.5 grams Look for “partially hydrogenated vegetable oil” or “vegetable shortening” IOM recommends trans fat intake be “as low as possible”

45. Fat Substitutes “New” vegetable oils from “new” seed –Soybean & other seeds with very low levels of linolenic acid More stable but less omega-3 fatty acid Fat substitues –Z-Trim made from corn, soy, oat fiber –Oatrim made from whole oats Fat replacers –Artificial fats Olestra

46. High-Fat Foods Changing guidelines for fat intake

47. High-Fat Foods Cook with olive oil or canola oil Monounsaturated fatty acids Nibble on nuts Omega-3 polyunsaturated fatty acids Feast on fish Marine omega-3 PUFA But beware of mercury Limit fatty meats, whole milk products, and tropical oils

48. High-Fat Foods Limit hydrogenated fat foods –Fried foods (fried in solid fats) –Fast foods (prepared in partially hydrogenated oils/fats –Commercial baked goods –Snack foods

53. Health Benefits of Lipids

54. Objectives After reading Chapter 4, class discussion and learning activities, you will be able to –Describe the role of lipids in the body –Identify food sources of fats –Discuss lipid digestion, absorption and transport –Calculate calories from fat

55. Objectives Identify types (classification) of lipids Discuss the health related effects of lipids –Blood lipid profile –Omega fatty acids –Trans fatty acids –Hydrogenation