Lipids and Protein

Question 1

What are the functions of Lipids (6)?

Answer 1

1. Components of cell membranes and steroid hormones
2. Essential Nutrients
3. Provide Energy
4. Help transport fat-soluble nutrients throughout the body
5. Contribute to the flavour and texture of food
6. Used to transfer heat during food preparations

Question 2

What are triglycerides?

Answer 2

• Three fatty acids on a glycerol backbone.
• 95% of consumed lipids
• Called fats(animal) and oils(plants) in food
• Stored in adipose tissue on the body

Question 3

What are phospholipids?

Answer 3

• 2% of consumed lipids
• Soluble in fat and water
• A major component of the cell membrane, glycerol.
• Lecithin, choline head group, is used for cooking spray and is key for milk molecule formation

Question 4

What are Sterols?

Answer 4

• Primarily produced in body
• Include cholesterol
• Contain no fatty acids, have multiple sterol rings
• Cholesterol precursor to steroid hormones.
• HDL - high-density lipoprotein - Carries impurities out of your cells
• LDL - Low-density lipoprotein - Carries dietary fats into your cells

Question 5

What are good fats?

Answer 5

Monounsaturated fatty acids
Polyunsaturated fatty acids
Cis form - Natural

Fish has trans-PUFA and omega-3.

Due to kink in molecules, stays liquid at RTP.

Cis-unsaturated fatty acids, convincingly reduce the risk of CHD. Also, it reduces LDL concentration which is associated with lower cholesterol in blood.

Question 6

What is the omega 3/omega-6 ratio? How is omega-3 healthy?

Answer 6

They are Essential and can not be made by the body

Omega-6/Omega-3 Ratio is important. Should be 2:1. Modern man has high omega 6 consumption and so the ratio is more like 20:1. This will lead to pro-inflammatory effects.

Omega-3
EPA →  Eicosapentaenoic Acid
Heart health, joint health, immune response
DHA → Docosahexaenoic Acid
Brain Development, Cognitive Function

Question 7

What is the smoke point? And what is acrolein?

Answer 7

Smoke point = the temperature at which oxidation and breakdown of lipids occur

Decomposition of lipids leads to acrolein (toxic) and water

Acrolein is carcinogenic

SFA smoke at lower temps than MUFA/PUFA

Question 8

What is bad fats?

Answer 8

Saturated Fatty Acids
Results in high LDL concentrations, which raise cholesterol in the blood.
Due to only single H-C bonds, stays solid at RTP.

Unsaturated Fatty Acids in the Trans-form
Raises LDL and lowers HDL. Significantly increases cholesterol in the blood.
Turning vegetable oil into margarine requires hydrogenation to saturate the triglyceride molecules, this can lead to the formation of Trans form unsaturated fatty acids, which have been linked to CHD.

Question 9

What are proteins? What is the distinction between essential and non-essential amino acids?

Answer 9

Proteins are Complex Polymers of amino acids.

Essential amino acids can not be created by the body.

Question 10

What are Complete proteins? What are incomplete proteins?

Answer 10

Complete proteins are proteins that contain all the essential amino acids, all animal-based sources of protein, and some plant-based protein.

Incomplete Proteins is a protein that is low on or missing some essential amino acids. There are only plant-based sources of incomplete proteins.

Question 11

What are complementary proteins?

Answer 11

Complementary proteins → the protein of one plant-based food can provide the essential amino acids that the other plant-based food is missing. (Legumes + Grains, rice and beans)