L17 Omega-3 and Omega-6 Fatty Acids Flashcards
What is each number/letter representative of in PUFA nomenclature?
22:5n-3
22 - number of carbon atoms in the chain
5 - number of double bonds in the carbon chain
n-3 - position of the first double bond from the methyl/omega/terminal end
What are the essential fatty acids? (2)
Omega 3
Omega 6
What is omega 3 also known as?
Alpha-linolenic acid
What is omega 6 also known as?
Linoleic acid
What essential fatty acid has the nomenclature 18:3n-3?
Omega 3/Alpha-Linolenic Acid
What essential fatty acid has the nomenclature 18:2n-6?
Omega 6/Linoleic Acid
What does ‘essential fat’ mean?
Can not be synthesised in the body and is required from the diet
What are the two sources of PUFAs?
Omega-3 (ALA) and Omega 6
What is the class of monounsaturated fats?
What are some examples? (4)
Omega 9 fatty acids
- Olive oil
- Avocado
- Peanuts
- Almonds
What are some examples of Omega-6 FAs? (3)
- Corn oil
- Safflower oil
- Sunflower oil
What are some examples of ALA FAs? (3)
- Eicosapentanoic acid (fish, shellfish)
- Docosahexanoic acid (fish, shellfish)
- Alpha linolenic acid (flaxseed, soybean, walnut, rapeseed oils)
What PUFA is consumed more in a Western diet and by how much?
Omega-6 is consumed ~20x more than Omega-3
What is the major plant-based oil produced in the world?
Palm oil
What is the main type of fat in coconut oil?
Saturated fat
What is the main type of fat in olive oil?
Monounsaturated fat - Oleic acid (Omega 9)
How are the essential fatty acids stored in the body?
Esterified to phospholipids and stored in the lipid bilayer of plasma and nuclear membranes
How is diet related to the composition of cellular phospholipids?
- Omega 6 and omega 3 have competitive pathways
- These essential fatty acids (attained by the diet) are stored in the phospholipid cell membrane therefore what is consumed is what is stored
What is EPA?
Eicosapentaenoic acid - LC Omega 3 PUFA
What is DHA?
Docosahexaenoic acid - LC Omega 3 PUFA
How do EPA and DHA contribute to cellular membrane function? (4)
- Fluidity
- Membrane protein function
- Generation of intracellular signalling molecules
- Gene expression
What are the key cell types in which PUFAs play a role? (3)
- Neural
- Endothelial
- Platelets
What are eicosanoids? (1) What do they do? (1)
- Biologically active lipids
- Act as signalling molecules (localised hormones)
Do cells store eicosanoids? Why or why not?
Cells do not store eicosanoids
They are synthesised when required from fatty acids in cell and nuclear membranes
What are some key eicosanoids? (3)
- Prostaglandins (produced by the prostate gland)
- Leukotrines (produced by leukocytes)
- Thromboxanes (produced by platelets; thrombocytes)
What is arachidonic acid?
Omega 6 PUFA
What is the recommended Omega 6 to Omega 3 ratio?
2:1 (Omega 6 to Omega 3)
What are some benefits of omega-3 fatty acids? (5)
- Anti-inflammatory effects
- Membrane stabilising effects
- Anti-thrombotic effects
- Lipid lowering effects
- Plaque stabilisation effects
a) What is PGE2? (1)
b) What effects can it have on the body? (5)
a) Prostaglandin E2 is a pro-inflammatory mediator from eicosanoids (arachidonic acid)
b) Effects on the body:
- Induces fever
- Increases vascular permeability
-Increases vasodilation
- Causes pain
- Increases production of other inflammatory mediators
a) What is LTB4? (1)
b) What effects can it have on the body? (5)
a) Leukotriene B4 is a pro-inflammatory mediator from eicosanoids (arachidonic acid)
b) Effects on the body:
- Increases vascular permeability
- Enhances local blood flow
- Chemotactic for leukocytes
- Increased leukocytes ROS production
- Increases production of other inflammatory mediators
What is the role of eicosanoids in platelet aggregation?
Thromboxanes are the major eicosanoids produced by platelets
Initiates thrombus formation at sites of vascular injury or atherogenic plaque rupture
What are some potential health benefits of ALA? (2)
- Lower risk of CVD (cardioprotective)
- Lowering risk of cognitive impairment
What is the order of priority of fat consumption?
- Omega-3 PUFA
- Omega 6 PUFA
- MUFA
- Saturated FA
- Trans saturated FA
