1. Lipids Triglycerides Fats and oils Phospholipids Sterols Lecithin
Cholesterol

2. Objectives
After reading Chapter 4, class discussion and learning activities, you will be able to
Identify types (classification) of lipids
Describe the role of lipids in the body
Discuss lipid digestion, absorption and transport
Calculate calories from fat

3. Objectives Identify food sources of fats
Discuss the health related effects of lipids
Blood lipid profile
Omega fatty acids
Trans fatty acids
Hydrogenation

4. Triglycerides
p. 128
Fig 4-1 4

5. Triglycerides
glycerol

6. Triglycerides
glycerol + 3 fatty acids  triglyceride

7. Fatty Acids Length of fatty acid Degree of Saturation
18-24 carbons in length
Degree of Saturation
Saturated fatty-acid
Monounsaturated fatty-acid
Polyunsaturated fatty-acid
p. 129

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 NRAEF
p Fig 4-9

13. Phospholipids

14. Phospholipids 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 mg/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 Stomach Melting Lingual Lipase 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. Fat Digestion Enterohepatic circulation
How bile travels through the body

24. Fat DigestionOverview

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. Lipid Transport 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
Insure efficient use of protein and carbohydrate

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. Sources 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. How Dietary Fat Affects Blood Lipids
Type of Fatty Acid
Effects on Blood Lipids
Saturated
Polyunsaturated
Monounsaturated
Omega-3
Trans
- G Total Cholesterol G LDL Cholesterol - H Total, LDL, HDL Cholesterol - H Total, LDL G HDL Cholesterol - H Triglycerides, Total Cholesterol - G Total, LDL H HDL Cholesterol

39. Health Benefits of Lipids

40. Recommended Intakes of Fat
DRI: % of energy intake
Cholesterol: mg/day
Linoleic acid AI
5% - 10% of energy intake
Linolenic acid AI
% of energy intake

41. Guidelines to Groceries
Avoid ADDED and Invisible Fat
Avoid Tropical
oils
Coconut oil
Palm oil

42. Fat Distribution in Diet

43. Guidelines to Groceries
Use whole, unprocessed vegetables, fruits, and grains without added fats

44. Guidelines to Groceries
Use fat free milk and milk products

45. Guidelines to Groceries
Use meat sparingly
Use lean meats
Use meat alternatives

48. 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”

49. Fat Substitutes “New” vegetable oils from “new” seed Fat substitues
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

50. Changing Guidelines for
Fat Intake

51. Changing Guidelines Cook with olive oil or canola oil Nibble on nuts
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

52. Changing Guidelines Limit hydrogenated fat foods
Fried foods (fried in solid fats)
Fast foods (prepared in partially hydrogenated oils/fats
Commercial baked goods
Snack foods

55. Replacing Saturated Fat with Unsaturated Fat

57. Objectives
After reading Chapter 4, class discussion and learning activities, you will be able to
Identify types (classification) of lipids
Describe the role of lipids in the body
Discuss lipid digestion, absorption and transport
Calculate calories from fat

58. Objectives Identify food sources of fats
Discuss the health related effects of lipids
Blood lipid profile
Omega fatty acids
Trans fatty acids
Hydrogenation

59. The End!