Exam #1: Lipids

Question 1

What are the roles of fatty acids?

Answer 1

• Texture, aroma, and flavor for food
• Structural building blocks (molecules) of cellular membranes and are the starting materials for other molecules
• Fat-soluble vitamin absorption
• Insulation, cushioning, and lubrication
• Provide energy

*Note that fat is also essential for development

Question 2

How much energy comes from fat vs. carbohydrates?

Answer 2

Fat= 9 Cal 
Carb= 4 Cal

Question 3

What type of fat in the body is used for energy?

Answer 3

Triglycerides

Question 4

Describe the structure of a triglyceride.

Answer 4

Glycerol backbone + 3x fatty acids

Question 5

Describe the structure of a phospholipid.

Answer 5

Glycerol backbone + 2x fatty acids + 1x phosphate group

Question 6

What is a sterol?

Answer 6

Cholesterol/ ring structure based fat

Question 7

What is the difference between saturated and unsaturated?

Answer 7

Saturated= no double bonds, all hydrogen

Unsaturated= some double bonding

Question 8

What are the major dietary sources of saturated fat? What are the health consequences of consuming this kind of fat?

Answer 8

Meat, dairy, coconut palm, cocoa butter

• Increased risk of:
• CVD
• Hyperlipidemia

Question 9

What are the major dietary sources of monounsaturated fat? What are the health consequences of consuming this kind of fat?

Answer 9

Olive oil, avocado, canola oil

• May:
• Decrease LDL
• Cardioprotective

Question 10

What are the major dietary sources of polyunsaturated fat (omega-6)? What are the health consequences of consuming this kind of fat?

Answer 10

Corn, soy, sunflower, safflower

• Essential fatty acid
• Increases some inflammatory cytokines

Question 11

What are the major dietary sources of polyunsaturated fat (omega-3)? What are the health consequences of consuming this kind of fat?

Answer 11

Oily ocean fish, flax seed oil, canola & soy oils

• **Essential
• Decreased TGs
• Cardioprotective
• Brain health

Question 12

What are the major dietary sources of trans fat? What are the health consequences of consuming this kind of fat?

Answer 12

Frying and baking oils, margarine

• *****Worst for health:
• Increased LDL
• Decreased HDL
• Increased inflammatory cytokines

Question 13

What enzyme is essential for the digestion of fat?

Answer 13

Lipase (lingual, gastric, & pancreatic)

Question 14

What is the function of bile?

Answer 14

Pancreatic lipase rxn is highly reversible- bile keeps fat broken down

Question 15

Review the process of fat absorption.

Answer 15

N/A

Question 16

What are the consequences of lipid malabsorption?

Answer 16

Lipid soluble vitamin malabsorption

Question 17

What is the treatment for lipid malabsorption? Why?

Answer 17

Medium chain fatty (8-12) acids b/c they do not require micelles or bile salts for absorption

Question 18

Review the process of fat circulation in the body.

Answer 18

N/A

Question 19

What is chyluria?

Answer 19

Abnormal connection between urinary tract and lymphatic drainage system

*Milky urine

Question 20

What is a chylothorax?

Answer 20

Abnormal connection between pleural space and lymphatic drainage of small intestine

*Milky pleural effusion

Question 21

What are the products of B-oxidation? Where are these products entering the TCA cycle?

Answer 21

Even FA= acetyl-CoA

Odd= acetyl CoA & propionyl-CoA
- Succinyl-CoA

Question 22

How much total dietary fat is recommended per day?

Answer 22

~30g

Question 23

What is the ideal ratio for omega 6 & 3 consumption?

Answer 23

1:1 or 1:5

*****Note that we obtain much more omega-6 in our diet than omega-3; thus, omega-3 needs to be supplemented

Question 24

Aside from CAD, what diseases can be beneficially impacted by omega-3 supplementation?

Answer 24

Autoimmune

• Psoriasis
• RA
• Asthma
• MS
• DM-I

Depression
Dementia

Question 25

What is the difference between a cis and trans fat?

Answer 25

Cis= natural, unsaturated fatty acid

Trans= linear & similar to saturated fatty acids

Question 26

What is the argument for banning trans fat?

Answer 26

“Extension in shelf-life not matched by extension of human life

Question 27

What are the negative effects of dietary trans fat?

Answer 27

Dyslipidemia
Abdominal fat 
Systemic inflammation
Endothelial dysfunction
DM 
Membrane dysfunction

Question 28

What enzymes break down alcohol in the liver?

Answer 28

1) Alcohol dehydrogenase

2) Acetaldehyde dehydrogenase

Question 29

What are the four major metabolic effects of excess alcohol consumption?

Answer 29

1) Acetaldehyde toxicity
2) High NADH:NAD ratio
3) Metabolic competition
4) Induced metabolic intolerance

Question 30

What are the stages of liver damage?

Answer 30

1) Healthy
2) Fatty
3) Fibrosis
4) Cirrhosis

Question 31

What are the benefits of moderate alcohol consumption?

Answer 31

• Elevate HDL
• Slowed atherogenesis
• Decreased CAD