LIPIDS Flashcards
Lipid Definition
a lipid is
- soluble in non-polar solvents
- linked to fatty acids
- no toxic in the body
7 things lipids are important for
- main storage form of energy
- component of cell membranes
- provide insulation
- help control body temperature
- protect internal organs
- form basis of many hormones
- aids intestinal absorption of fat soluble vitamins
What is the most important thing in terms of lipids
Quality, to prevent chronic disease risk
Why are lipids important in for
- to enhance flavour, makes food taste good
- provides essential fatty acids, that our body can’t make so we need to get them from our diet
5 types of lipids
- triacylglcerol
- phosolipids
- sphingolipids
- sterols
- fat soluble vitamins
Triglyceride’s
- 90-95% - these are the most common type of lipid found in our body and food.
- These are made up of a glycerol backbone, and 3 attached fatty acids
- structural component of lipoproteins
Lipoproteins
these are made up of both lipids and proteins. as lipids are not soluble in water they can’t travel through blood by themself. so the get into protein to travel through blood
Phospholipids
- makes up 5-10% of lipids
- found in cell membranes, and are apart of their structural components
- made up of a glycerol backbone, 2 fatty acids and a phosphate
- they are information molecules
Cholesterol
- is only found in animals, so vegans get a 0 intake of it. but our liver can make it so we don’t need to eat it
- has bile acids as break down fats
- in cell membranes it keeps the fluid in a fluid state
Fatty Acids
- these are the main energy source
- these are information molecules. it is important that these essential fats are in our diet as they have important roles in our bodies
Fatty Acid Classification
Short Chain - C2-6 = absorbed straight away
Medium Chain - C8-12 = absorbed straight away
Long Chain - C14-21 = go through lymphatic system first
Very Long Chain - C22 + = go through lymphatic system first
most diet foods are C10-22
Saturated Fatty Acids
C18:0
18 carbons
0 double bonds
methyl CH3 and carboxyl end
- have high MP points
- not essential
Monounsaturated Fatty Acids
C18:1n-9
18 carbons
1 double bond @ carbon 9
- one cis or trans bond
- not essential
Polyunsaturated Fatty Acid
C18:2w-6
18 carbons
2 double bonds, the first one at the 6th carbon. the CH2 separates the double bonds
when n3 or n6 they are essential acids as can not be made in the body
Essential Fatty Acids
humans are not able to produce a double bond from the C from a methyl or omega end, therefore we most obtain the fatty acids that have double bonds before the 9th carbon in our diet
- they should make up at least 1-3% of all daily energy intake
- deficiencies are unusual in NZ, with most people eating more then the minimum requirements
Trans vs Cis
trans is on opposite sides whilst, cis is on the same sides.
trans have higher melting points, and are bad for you as they increase cholesterol
what are the metabolic states of fatty acids
- found in the cell membrane
- Eicosanoids
- energy
- storage
Saturated fatty acid examples
coconut and palm oil
butter
Monounsaturated fatty acid examples
olive, canola, peanut oil
Polyunsaturated fatty acid examples
Safflower, flaxseed, walnut, sunflower, corn, soybean, cottonseed oil.
Saturated flat’s effect on CVD
saturated fat increases cholesterol (LDL), which increases the risk of CVD. But the LDL receptors absorb the cholesterol from the blood.
PUFA effect on cholesterol
PUFA decreases cholesterol, which increases LDL receptor activity, which increases CYP7 which converts cholesterol to bile acids.
High Fat Diets Theory
during endurance exercise, this allows athletes to use more fat and less CHO. Some studies show that those on a high fat diet see similar metabolic changes.
Why would you want to enhance fat metabolism
- CHO oxidation is increased, reducing fat oxidation
- this will leave spare muscle glycogen
- unlike CHO there is unlimited storage of fat
- fat is more energy dense that CHO
One disadvantage of high HCO diets
you have to eat lots of food to reach your goal of high CHO
Advantages of Fat as fuel
energy dense
extensive body stores
Disadvantages of Fat as fuel
- CHO produces greater ATP per unit of oxygen so it costs more oxygen
- transportation in blood
- cannot be used anaerobically
Factors effecting fat oxidation during exercise
exercise …
- intensity
- duration
- preceding diet
- training status
- CHO availability
Research of a high fat diet
in animals it helps them but in humans it is more controversial
Short term (1-3 days) adaptions for high fat diets
no changes overall
Short term (5-10 days) adaptions for high fat diets
there are metabolic changes, leading to more fat oxidation, but these is not any benefit to athletes
longer term adaptions (3+weeks)
- they have a higher HR, so they don’t feel as good when they exercise. whilst fat oxidation does increase. it is proven the performance stay the same or get worse
Summary of high fat diets on performance
majority of studies show no difference in endurance when comparing adaptions to high fat and high CHO diet
they should be done periodisation, with training cycles, not for long periods of time
4 things that need to be considered when designing diets for athletes
- individual preference
- total energy expenditure
- time for recovery
- nature of the sporting event
