1. Lipids
Chapter 06

2. What Are Lipids? Organic macronutrients Roles of lipids Oil Fat
Insoluble in water
Hydrophobic
Roles of lipids
Oil
Liquid at room temperature
Fat
Solid at room temperature
Major lipids

3. What Are Lipids? Fatty acids
Most abundant type of lipid in body and diet
Structure
Carbon chain
Alpha end – carboxylic acid group
Omega end – methyl group
Types
Number of carbons
Types & locations of chemical bonds

4. Fatty Acid Structure

5. Fatty Acids, Triglycerides, and Phospholipids

6. What Are Lipids? Fatty acids Chain length
Most naturally-occurring fatty acids have even number
Short-chain, medium-chain, and long-chain fatty acids
Chemical properties
Physiological functions
Solubility in water

7. Fatty Acids Can Have Different Chain Lengths?

8. What Are Lipids? Fatty acids Chemical bonds Single bonds Double bonds
Saturated fatty acids (SFAs)
Double bonds
Monounsaturated fatty acids (MUFAs)
Polyunsaturated fatty acids (PUFAs)
Chemical nature

9. Saturated & Unsaturated Fatty Acids

10. What Are Lipids? Fatty acids Cis double bonds Trans double bond
Hydrogens on same side of double bond
Trans double bond
Hydrogens on opposite sides of double bond
Trans fatty acids in food
Naturally occurring
Hydrogenation

11. Cis versus Trans Fatty Acids
Insert figure 6.5 from page 128 here

12. What Are Lipids? Naming fatty acids Characteristics
Alpha naming system
Relative to carboxylic acid end
Omega naming system
Double bond’s distance from the methyl end
Omega-3 and omega-6 fatty acids
Common names

13. The Alpha (α) Naming System

14. What Are Essential, Conditionally Essential, & Nonessential Fatty Acids?
Linoleic acid
18 carbons; 2 double bonds; omega-6 fatty acid
Arachidonic acid
Linolenic acid
18 carbons; 3 double bonds; omega-3 fatty acid
EPA
DHA

15. What Are Essential, Conditionally Essential, & Nonessential Fatty Acids?
Eicosanoids
Roles
Omega-6 eicosanoids
Cause inflammation and constriction of blood vessels
Omega-3 eicosanoids
Reduce inflammation and stimulate dilation of blood vessels

16. Fatty Acid Metabolism & Eicosanoid Formation

17. What Are Essential, Conditionally Essential, & Nonessential Fatty Acids?
Deficiency
Primary
Rare
Secondary
Diseases that disrupt lipid absorption
Cystic fibrosis

18. What Are Essential, Conditionally Essential, & Nonessential Fatty Acids?
Conditionally essential fatty acids
Infancy
Arachidonic acid
DHA
Dietary sources of fatty acids
Linoleic acid
Linolenic acid
EPA and DHA

19. What Are Essential, Conditionally Essential, & Nonessential Fatty Acids?
Dietary sources
SFAs
PUFAs
MUFAs
Roles

20. Distribution of Fatty Acid Types in Commonly Consumed Lipids

21. What Is the Difference between Mono-, Di- & Triglycerides?
Number of fatty acids in chemical structure
Saturation of fatty acids
Lipogenesis
Fatty acids combine with glycerol

22. Triglyceride Structure

23. What Is the Difference between Mono-, Di- & Triglycerides?
Richest source of energy
9 kcal per gram
Lipolysis
β-oxidation
Ketones
Ketogenesis

24. What Is the Difference between Mono-, Di- & Triglycerides?
Storage in adipose tissue
Adipocytes
Stored as triglycerides
Advantages
Location of adipose tissue
Subcutaneous vs. visceral adipose tissue
Role of insulin
Insulation

25. What Are Phospholipids and Sterols?
Roles
Cell membranes
Transport of lipids in bloodstream
No dietary requirements for either of them

26. What Are Phospholipids and Sterols?
Has two fatty acids
Phosphate-containing hydrophilic head
Amphipathic
Roles
Cell membranes
Digestion, absorption, and transport of lipids
Other functions

27. Phospholipid Structure

28. Cell Membrane Made from Phospholipid Bilayer

29. What Are Phospholipids and Sterols?
Multi-ring structure
Cholesterol
Synthesis of bile acid
Component of cell membranes
Reproductive hormones
Other roles
Sources
Phytosterols

30. Structure of Cholesterol

31. Cholesterol Content of Selected Foods

32. How Are Triglycerides Digested, Absorbed, & Circulated?
Basic goal of digestion
Mouth
Lingual lipase
Stomach
Gastrin
Gastric lipase

33. Overview of Triglyceride Digestion

34. How Are Triglycerides Digested, Absorbed, & Circulated?
Small intestine
Phase 1: Micelle formation
Bile disperses large globules into smaller droplets
Emulsification
Gallbladder disease
Removal of gallbladder

35. Emulsification of Lipids to Form Micelles in the SI

36. How Are Triglycerides Digested, Absorbed, & Circulated?
Small intestine
Phase 2: Pancreatic lipase
Secretin
Release of pancreatic lipase
Final products of lipid digestion
Fatty acids
Glycerol
Monoglycerides

37. How Are Triglycerides Digested, Absorbed, & Circulated?
Absorption
Two ways
Unassisted transport into intestinal cells
Short- and medium-chain fatty acids
Repackaging into micelles in lumen
Contents released into intestinal cell’s interior

38. How Are Triglycerides Digested, Absorbed, & Circulated?
Circulation
Depends on hydrophilic nature of lipid
More hydrophilic
Circulation in blood attached to albumin
Circulates to liver
Less hydrophilic
Circulated in lymph
Lipoproteins
Liporotein lipase

39. Absorption & Circulation of Lipids

40. The Lipoproteins

41. What Are the Types & Functions of Various Lipoproteins?
Produced in the liver
Transport lipids in the blood
Complex globular structures
Apoprotein
Chylomicron
Largest and least dense
Produced in small intestine
Transport dietary lipids exclusively

42. Origins and Major Functions of Lipoproteins

43. What Are the Types & Functions of Various Lipoproteins?
Very low-density lipoprotein (VLDL)
Lower lipid-to-protein ratio than chylomicrons
Primary function
Low-density lipoproteins (LDL)
LDL receptors
“Bad” cholesterol
Plaque
Intermediate-density lipoprotein (IDL)

44. What Are the Types & Functions of Various Lipoproteins?
High-density lipoproteins (HDL)
Lowest lipid-to-protein ratio
Collect excess cholesterol
Transport it back to the liver
“Good” cholesterol
Different types
Not equally effective in removing cholesterol

45. How Are Dietary Lipids Related to Health?
High-fat foods and obesity
Major public health concern
Associated health risks
Fat substitutes
Examples
Typically made from carbohydrates or proteins
Products may be fat free, but not calorie free

46. How Are Dietary Lipids Related to Health?
Cardiovascular disease
Common types
Heart disease
Stroke
Atherosclerosis
Blood clot
Aneurysm
Lipids of concern
Genetics

47. Causes of Cardiovascular Disease

48. How Are Dietary Lipids Related to Health?
Cardiovascular disease
Nutritional guidelines
Moderate overall energy intake
Balance your macronutrients
Whole grains
Dietary fiber
Cancer
Recommendations

49. What Are Some Overall Dietary Recommendations for Lipids?
Essential fatty acids
Consume adequate amounts
DRIs
AIs
Omega-3 fatty acid intake
Limit cholesterol, SFAs, and Trans fat
Dietary guidelines
Total lipid consumption
AMDRs

50. Reading Nutrition Facts Panels