1. Triglycerides Phospholipids Sterols
The Lipids
Triglycerides
Phospholipids
Sterols

2. Triglycerides Phospholipids Sterols
The Lipids
Triglycerides
Phospholipids
Sterols

3. Bacon Everywhere?
I’m not trying to be political, watch starting at 2:20 (till 3:45) for a profound “are you kidding me” moment on the state of nutrition in America.

4. Macronutrients: Our Main Questions
What are they?
What do they do in us?
Where do they come from?
Structure
Digestion
Metabolism and Storage
Recommended Allowances
Consequences of too much
Consequences of too little
Other Issues (substitutes, etc.)

5. Lipids: What are They?

6. Lipids: What are They? Saturated fat Unsaturated fat
Polyunsaturated fat
Monounsaturated fat
But also,
Cell membranes
Myelination
Cell signaling

7. Lipids: What do they do?
Lipids in foods and in the human body fall into three classes
Triglycerides
≈95% of all lipids in foods and the human body
Phospholipids
For example, lecithin
Form the “walls of your cells”
Sterols
For example, cholesterol
Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

8. Lipids: What do they do?
Fat is the body’s major storage form of energy
Fats pack tightly together without water
Relative to carbohydrate, much more fat can be stored in a small space
Gram for gram, fats provide more than 2x the energy of carbohydrate
Making fat an efficient storage form of energy

9. Lipids: What do they do?

10. Lipids: What do they do?

11. Lipids: What do they do?

12. Lipids: Where do they come from?

13. Structure: Fatty Acids and Triglycerides
Glycerol

14. Structure: Fatty Acids and Triglycerides
glycerol + 3 fatty acids  triglyceride + H2O

15. Structure: Fatty Acids
Length
Saturated vs. unsaturated
Point of saturation

16. Structure: Fatty Acid Length
Stearic acid – 18-carbon, saturated

17. Structure: Fatty Acid Saturation
Degree of saturation (how many)
Saturated (0) fatty acid
Monounsaturated (>1) fatty acid
Polyunsaturated (>1) fatty acid

18. Structure: Fatty Acid Saturation
Degree of saturation (how many)
Saturated (0) fatty acid
Monounsaturated (>1) fatty acid
Polyunsaturated (>1) fatty acid

19. Structure: Fatty Acid Saturation
Degree of saturation (how many)
Saturated (0) fatty acid
Monounsaturated (=1) fatty acid
Polyunsaturated (>1) fatty acid

20. Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated
Fats are like toothpicks, the straighter they are, the tighter you can pack them (and make them solid)

21. Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated
Degree of saturation
Affects the temperature at which the fat melts
In general, the more unsaturated the fatty acids, the more liquid the fat is at room temperature
In general, the more saturated the fatty acids, the firmer the fat is at room temperature

22. Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated
Degree of saturation

24. Structure: Fatty Acid Saturation Saturated, Monosaturated, and Polyunsaturated
To determine if an oil you use contains saturated fats
Place the oil in the refrigerator and watch for cloudiness
Because it is solidifying
The least saturated oils remain the clearest

25. Structure: Point of Saturation
Location of double bonds
Omega number
Omega-3 fatty acid
Omega-6 fatty acid
How does the body use each differently?

26. There is more to it, if you’d like to look.

27. Fish Oil and Heart Disease

28. There is more to it, if you’d like to look.

29. Structure: Degree of Saturation and Spoilage
Degree of unsaturation revisited
Firmness
Stability
Oxygen breaks down carbon bonds and makes food rancid.

30. Structure: Degree of Saturation and Spoilage
Rancid Fresh
Oxygen breaks down carbon bonds and makes food rancid.
Unsaturated fats are most stable.
Polyunsaturated fats spoil more rapidly.

32. Triglycerides The food industry has come up with two solutions.
Hydrogenation
Turn unsaturated fats to saturated fats. It makes them more solid in your blood vessels.
Trans fats.
Reorient the double bonds to make them less susceptible to oxygen.

33. Triglycerides
The food industry has come up with two solutions.

34. Hydrogenation

35. Cis- and Trans-Fatty Acids Compared

36. Where are Trans Fats: Partially Hydrogenated

37. Transition

38. Lipids: What are They
Lipids in foods and in the human body fall into three classes
Triglycerides
≈95% of all lipids in foods and the human body
Phospholipids
For example, lecithin
Form the “walls of your cells”
Sterols
For example, cholesterol
Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

39. Phospholipids

40. Phospholipids
Phospholipids = 2 fatty acids + glycerol + a phosphorus-containing molecule
Fatty acid is soluble in fat
Phosphorus is soluble in water
Phospholipids are emulsifiers
A substance that mixes with both fat and water and permanently disperses the fat in the water
Forming an emulsion

41. Phospholipids

42. Phospholipids

43. Cholesterol Strengthens Cell Membranes:

44. Cholesterol Strengthens Cell Membranes: But keep it in check

45. Lipids: What are They
Lipids in foods and in the human body fall into three classes
Triglycerides
≈95% of all lipids in foods and the human body
Phospholipids
For example, lecithin
Form the “walls of your cells”
Sterols
For example, cholesterol
Aid in digestion and are the building blocks of hormones like testosterone, estrogen and progesterone.

46. Sterols
Large, complicated molecules consisting of interconnected rings of carbon atoms with side chains of carbon, hydrogen, and oxygen

47. Sterols The sterol cholesterol serves as the precursor for making bile
Component of cell membranes
Can be made by the body
Not an essential nutrient
Forms the major parts of the plaques that narrow arteries in atherosclerosis
Vitamin D and sex hormones are also sterols

48. Sterols The sterol cholesterol serves as the precursor for making bile
Component of cell membranes
Can be made by the body
Not an essential nutrient
Forms the major parts of the plaques that narrow arteries in atherosclerosis
Vitamin D and sex hormones are also sterols

49. transition

50. Fat DigestionOverview

51. Fat Digestion Small intestine Bile Produced by the liver
Stored in the gallbladder
Secreted in the small intestine
Emulsifies fat

52. Fat Digestion

55. Lipid Transport

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

57. Lipid Transport
Lipoproteins and health
LDL vs. HDL

59. 1. Fats are absorbed from the intestine as VLDL

60. As fats move through the blood stream, they drop off lipids.

61. 3. As they do, they carry less lipid (making them higher in density)
VLDL →LDL→HDL

62. 4. If there is already lots of fat in the blood vessel, fat is not dropped off.

63. 5. Fat gets dumped off anyway and sticks to the vessel wall, clogging arteries.

65. Lipoproteins and Heart Disease Risk
→HDL
The LDL and HDL difference
LDL
Larger, lighter, and richer in cholesterol than HDL
Deliver triglycerides and cholesterol from the liver to tissues
HDL
Smaller, denser, and packaged in more protein than LDL
Scavenge excess cholesterol and phospholipids from tissues for disposal
←LDL

66. Lipoproteins and Heart Disease Risk
Elevated LDL concentrations in the blood are an indication of heart attack risk
Why?
Elevated HDL concentrations in the blood are associated with a low heart attack risk
The difference is attributable to the proportions of lipids they contain and the tasks they perform
The difference is not in the type of cholesterol they carry
→HDL
←LDL

67. Lipoproteins and Heart Disease Risk
Risk factors that cannot be changed
Increasing age
Being male
Family history of premature heart disease

68. Lipoproteins and Heart Disease Risk
Risk factors that a person can often control
High blood LDL; low blood HDL
High blood pressure
Diabetes
Obesity
Physical inactivity
Cigarette smoking
Atherogenic diet
Get more fiber

69. Wouldn’t It Be Nice To Have a List of Foods High in HDL and LDL
Well, its not in your book, so we will have to make that list ourselves.
10 points.
Find 5 foods high in HDL
Find 5 foods high in LDL
Submit it to me (handwritten is fine)
I will assemble the list for us.

70. Translation: More fiber = less bile
Less bile = less fat absorption

71. High-Fat Foods Seven Countries Study of healthy people
Death rates from heart disease were strongly associated with diets high in saturated fats
Death rates from heart disease were only weakly associated with diets high in total fat
Finland & the Greek island of Crete were the two countries with the highest fat intake
Finland had the highest rate of death from heart disease
Crete had the lowest rte of death from heart disease

72. High-Fat Foods Finland vs. Crete
Both consume 40+% of calories from fat
Thus, total fat was not the culprit in heart disease
Relative to Finland people in Crete had a diet
High in olive oil
Low in saturated fat
Less than 10% of calories
After an average follow-up of 46 months (almost four years), patients following the Mediterranean-style diet had a 50–70 percent lower risk of recurrent heart disease.

73. High-Fat Foods People naturally like high-fat foods
As fat becomes less expensive and more available in a given food supply, people seem to choose diets providing greatly increased amounts of fat
Fats carry many dissolved compounds that give foods enticing aroma and flavors
Fat also lends a tenderness to foods such as meats and baked goods

74. Recommended Intakes of Fat
DRI: 20% - 35% of energy intake
Or, pick who you trust…
DRI
WHO
AHA

76. Cutting Fat Cuts kCalories and Saturated Fat

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

79. High-Fat Foods
Limit fatty meats, milk products, and tropical oils

80. High-Fat Foods
Limit hydrogenated foods

85. Other Issues: Fat Substitutes
Fat replacers
Artificial fats
Olestra

86. Olestra
Fat replacers
Artificial fats
Olestra

87. High-Fat Foods
Changing guidelines for fat intake