Chapter 6 Lipids Objectives: • Describe the lipids of major biological importance; their basic structure and function • Understand how lipids are digested and absorbed by the GI tract; how they are transported and stored in various locations • Understand how lipids are packaged into various types of lipoproteins; how these lipoproteins can be distinguished from one another, and how they are related to cardiovascular disease. • Learn how the major lipids are metabolized via oxidation, how ketones are formed, and how we regulate the manufacture and breakdown of cholesterol • Understand how lipid metabolism is regulated, and how diet and pharmaceutical aids target this regulation • Learn how some fats are “good” for you and can potentially prevent disease
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Chapter 6 Lipids Objectives: Describe the lipids of major biological importance; their basic structure and function Understand how lipids are digested.
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Chapter 6 Lipids
Objectives:
• Describe the lipids of major biological importance; their basic structure and function
• Understand how lipids are digested and absorbed by the GI tract; how they are transported and stored in various locations
• Understand how lipids are packaged into various types of lipoproteins; how these lipoproteins can be distinguished from one another, and how they are related to cardiovascular disease.
• Learn how the major lipids are metabolized via oxidation, how ketones are formed, and how we regulate the manufacture and breakdown of cholesterol
• Understand how lipid metabolism is regulated, and how diet and pharmaceutical aids target this regulation
• Learn how some fats are “good” for you and can potentially prevent disease
• Learn about the thermogenic capacity of brown fat and how it differs from yellow fat
• By 2020 about one in five health care dollars spent on people ages 50-69 could be consumed by obesity-related medical problems -- up about 50 percent from 2000.
• The proportion of health care expenditures associated with treating the consequences of obesity would increase from 14 percent in 2000 to 21 percent in 2020 for 50-69 year-old men, and from 13 percent to 20 percent for women in the same age group.
• Many of the improvements in health achieved by middle-aged and older Americans in recent decades as a result of medical advances could largely be erased over the next two decades if population weight continues to increase.
(EPA – eicoapentaenoic acid, and DHA – docosahexaenoic acid)
Hypolipidemic effects
Antithrombotic effects
Table 6-1, p. 131
Fig. 6-3, p. 132
Triglycerides
medium chain triglycerides
- weight gain
- athletic performance
Fig. 6-7, p. 133
Sterols
Fig. 6-8, p. 134
Fatty Acid and Cholesterol Composition of Some Common Fats
Saturatedg/Tbsp
Monounsaturatedg/Tbsp
Polyunsaturatedg/Tbsp
Cholesterolmg/Tbsp
Canola Oil 1.0 8.2 4.1 0
Safflower Oil 1.2 1.6 10.1 0
Sunflower Oil 1.4 2.7 8.9 0
Corn Oil 1.l7 3.3 8.0 0
Olive Oil 1.8 9.9 1.1 0
Sesame Oil 1.9 5.4 5.7 0
Soybean Oil 2.0 3.2 7.9 0
Peanut Oil 2.3 6.2 4.3 0
Vegetable Shortening 3.2 5.7 3.3 0
Chicken Fat 3.8 5.7 2.7 11
Lard 5.0 5.8 1.4 12
Beef Tallow 6.4 5.3 0.5 14
Butter 7.1 3.4 0.6 31
Coconut Oil 11.8 0.8 0.2 0
Fig. 6-11, p. 135
Phospholipids (two types)
1. Glycerophosphatides phosphatidylcholine (lecithin) -protection from alcoholic cirrhosis -synthesis of eicosanoids phosphatidylserine (rice & GLVs) -”brain booster” (beware viruses) - athletic performance phosphatidylinositol (whole, unprocessed grains, citrus fruits cantaloupe, brewer’s yeast, unrefined molasses, and liver. It is also available in wheat germ, lima beans, raisins, peanuts, cabbage, and some nuts) -anchoring membrane proteins -synthesis of eicosanoids
Virgin Olive Oil vs. Lite Olive Oil vs. Extra Virgin Olive Oil
•All virgin olive oils are extracted mechanically from the olives. No processing or other processes other than filtering have been done to the oil.
•Virgin vs. Extra Virgin refers to the concentration of oleic acid present in the oil. The oleic acid lowers the pH. The lower the pH, the less “taste” of the olive is present.
•Olive oil is monounsaturated and has to be heated to very high temperatures to be converted to its trans form. This is highly likely in industrial fryers, but relatively unlikely to happen on the cooking stove in a home.
PGH2 synthases = Cox1 and Cox 2
Table 6-5, p. 160
Fig. 6-9, p. 134
2.Sphingolipids
- Sphingomyelins
Intestinal mucosal cell
Endoplasmic reticulum
HDL
Lymphatics
FA-albumin
Lysophosphatidylcholine
(direct absorption)
Monoacylglycerols
Free fatty acids
Glucose
Glycerol
Micellarparticles
Cholesterol
LYSPCCHYLO
Apoprotein
FA-CoACE
Short-chain FFA
PC
TG
Albumin
MG
CHOL
a-GP
Portalcirculation
Fig. 6-16, p. 139Lipid Transport and Storage
Peripheral apoprotein (e.g., apoC)
Phospholipid
Cholesterylester
Triacylglycerol
Core of mainly nonpolar lipids
Monolayer of mainly polar lipids
Integral apoprotein(e.g., apoB)
Free cholesterol
Fig. 6-17, p. 140
Table 6-3, p. 140
Table 6-4, p. 141LCAT = lecithin:cholesterol acyltransferase
Fig. 6-18, p. 142
Fig. 6-19, p. 143
Fig. 6-20, p. 144
Metabolism of Circulating Lipoproteins
Things to remember:
• LDLs are the major carrier of cholesterol to tissues, where it may be used for membrane construction or converted into other metabolites.
• HDLs remove cholesterol from cells and other lipoproteins and return it to the liver for excretion in the bile.
LDL receptor(coated pit)
CholesterylLinoleate
Protein
(b)(a)
LDL
LDL binding
Lysosome
Internalization Lysosomal hydrolysis
Amino acids
Cholesterol
Cholesteryloleate
3.pLDL receptors
2.qACAT
1.pHMG CoAreductase
Regulatory actions
Fig. 6-21, p. 145
How cells know whether to take or give away cholesterol