1. Triglycerides Phospholipids Sterols
The Lipids
Triglycerides
Phospholipids
Sterols

2. Lipids
Triglycerides (TG)
Fats and oils
Phospholipids
Sterols

3. Fatty Acids (FA) & TG glycerol-a sugar alcohol, backbone of a FA!
REM: they have carbon (C), so they are organic!

4. FA & TG
glycerol + 3 FA TG + H2O

5. Condensation of Glycerol & Fatty Acids to Form a Triglyceride

6. Fatty Acids Length (size matters) Saturated vs. unsaturated
Acetic Acid (most simple)

7. Saturated Fatty Acids How many carbons? Stearic acid – 18-carbon
Simplified structure

8. Fatty Acids Point of saturation (where?)
Degree of saturation (how much?)
Saturated fatty acid
Monounsaturated
Polyunsaturated

9. An impossible chemical structure: Why?
Oleic acid – 18-carbon, monounsaturated
Linoleic acid – 18-carbon, polyunsaturated

10. OMEGA NUMBER: Ω-3 vs. Ω-6 Fatty Acids

11. TG: Why Does Saturation Matter?
Unsaturation effects:
Firmness
Stability
Oxidation
Antioxidants

13. Triglycerides:What about “hydrogenated oils?”
Hydrogenation-hydrogen added to mono- or polyunsaturated fats to make them solid by reducing the number of double bonds (C=C).
Cis vs. trans-fatty acids

14. Hydrogenation

15. Cis- and Trans-Fatty Acids Compared
So what? It’s a nice picture.

16. Trans fats are bad!!!
In the body trans fats behave like saturated fats! Why?
They contribute to higher LDL cholesterol and lower levels of "good" HDL cholesterol = heart disease.

17. Phospholipids

18. Phospholipids (PL) Phospholipids in foods Roles of PL Plasma membrane
Emulsifiers (help oil and water exist together)

19. Membrane Structure PL
Hydrophobic tail vs. hydrophilic head: more on this later.

20. Sterols

21. Sterols Roles of sterols: Good Bile acids Sex hormones
Adrenal hormones
Vitamin D
Roles of sterols: Bad
-Atherosclerosis-hardening of arteries.

22. Fat Digestion
Yummy...or not.

23. Fat Digestion Hydrolysis
Triglycerides  monoglycerides, fatty acids, glycerol

24. Fat Digestion

25. Fat Digestion
Mouth
Melting
Lingual lipase

26. Fat Digestion
Stomach
Churning and mixing
Gastric lipase

27. Fat Digestion Small intestine CCK-hormone which signals bile release!
Bile emulsifies fats.

28. Fat Digestion

29. Fat Digestion

30. Fat Digestion
Small intestine
Pancreatic lipases
Intestinal lipases

31. Fat DigestionOverview

32. Fat Digestion Enterohepatic circulation
Note how fiber helps remove excess cholesterol!!

35. Lipoproteins and health
Factors that lower LDL and raise HDL
Weight control
Replace saturated fat with monounsaturated fat and polyunsaturated fat in the diet
Soluble fibers
Phytochemicals
Moderate alcohol consumption
Physical activity (biggest helper)
Genes influence lipoprotein activity.

36. Roles of Triglycerides
Fat stores
Energy
Protection
Insulation

37. Essential Fatty Acids

38. Fat Metabolism

39. Storage as fat
Adipose tissue
LPL = lipoprotein lipase...fat storage.

40. Lipid Metabolism Using fat for energy
Hormone-sensitive lipase...triglyceride release.
Provides very little glucose...problem during fasting?

41. Health Effects of Lipids
Blood lipid profile
Heart disease
Risks from saturated fats

42. Health Effects of Lipids:US Diet

43. Dietary Cholesterol

44. Health Effects of Lipids
Benefits:monounsaturated and polyunsaturated fats
Cancer
Obesity

45. Health Effects and Recommended Intakes of Lipids
Recommended Intakes of Fat
DRI: 20-35% of energy intake ( kcalories of a 2,000-kcal diet).
FDA recommends 10% of energy intake from s
Linoleic acid AI Linolenic acid AI
5-10% of energy intake % of energy intake
aturated, 30% of energy intake total fat

46. Health Effects and Recommended Intakes of Lipids
Daily Values
65 g fat based on 30% of 2000-kcal diet
20 g sat. fat based on 10% of 2000-kcal diet
300 mg cholesterol
USDA Food Guide considers saturated fats discretionary kcalories.
Too little fat can be detrimental to health.

47. Health Effects and Recommended Intakes of Lipids
Health Effects of Lipids
Blood lipid profile
Reveals concentrations of lipids in the blood
Desirable levels
Total cholesterol < 200 mg/dL
LDL cholesterol < 100 mg/dL
HDL cholesterol ≥ 60 mg/dL
Triglycerides < 150 mg/dL

48. Cutting Fat Cuts kCalories and Saturated Fat

49. Guidelines to Groceries
Milk and milk products
Vegetables, fruits, and grains
Invisible fat

51. High-Fat Foods
Changing guidelines for fat intake

52. High-Fat Foods Cook with olive oil Nibble on nuts Feast on fish
But beware of mercury?

56. High-Fat Foods
Mediterranean diet?