Lipids
HI YA. i'm here to do boring notes again. :B
today it's about LIPIDS!
so these are the key points:
1. Define & Classify lipids
2. Identify food sources & fuel value of lipids
3. Explain digestion, absorption & functions of lipids
4. Describe role of lipids & blood lipids in health
5. State dietary recommendations for lipids
6. Describe effects of over-consumption & deficiency of lipids
okay, so firstly - classification !
1. Simple Lipids - Tryglycerides
-predominant lipid in foods & body!
-3 molecules of fatty acids linked to 1 molecule of glycerol
-stored in body in fat cells (adipocytes) in adipose tissues
2. Compound Lipids
-Phospholipids (eg lecithin) soluble in both oils & water
-Lecithin widely used as emulsifier
-Lipoproteins - transport lipids within body
4 main types of Lipoproteins
1. Chylomicrons - synthesized in small intestine
2. VLDL (Very-low-density Lipoproteins)
3. LDL (Low-density Lipoproteins)
4. HDL (High-density Lipoproteins)
How VLDL becomes LDL
-VLDL gives away tryglycerides to cells while picking up cholesterol
-thus, LDL
LDL is known as the "bad cholesterol".
LDL increases, risk of heart attack die to narrowed blood vessel increases.
HOWEVER,
HDL reduce risks of heart disease.
It picks up cholesterol from other tissues to be transported back to liver for breakdown & excretion.
3. Derived Lipids
-Sterol (eg cholesterol)
sterols naturally found in plants called phytosterols
cholesterol - found in animals!
Steroid hormones
(cholesterol converted into steroid hormones)
-have steroid nucleus in their structure
4. Lipid Related Compounds - Fat soluble vitamins (A, D, E, K)
More About Fatty Acids
1. Short chain fatty acids (less than 6 carbons)
eg dairy fats: milk, butter
2. Medium chain fatty acids (6-10 carbons)
eg coconut oil
3. Long chain fatty acids (more than 12 carbons)
eg found in human cells
Saturated fats (animal fats) - solid
Polyunsaturated (vegetable oil) - liquid
HYDROGENATION
-chemical process by which hydrogens are added to a double bond in a monosaturated or polyunsaturated fatty acid
-reduces no of double bond - fat more resistant to oxidation
-hydrogenation makes a fat more saturated
there are:
Cis & Trans Fatty Acids
Replace saturated fat with monounsaturated/polyunsaturated fat!
lowers blood cholesterol levels & lowers LDL & lowers risk for atherosclerosis and heart disease
Recommended Intake
-30% oe lwaa od out total energy should be from lipids
-Linoleic acid (omega-6)- 5-10%
-Linolenic acid (omega-3)- 0.6-1.2%
Functions
1. A concentrated source of energy
2. Main resting muscle fuel
3. Emergency/reserve fuel
4. As padding to protect internal organs
5. Insulate body from extremes of temperature
6. Form major component of cell membranes
7. As raw materials to synthesize body compounds
8. As carriers
9. Support health
Excessive Intake
1. Cardiovascular disease
-increase dietary intake of total fats (esp sat n trans fats) & cholesterol increases risk of atherosclerosis
2. Certain cancers
-diets (rich in fats esp animal fats), increases risk of certain cancers
3. Obesity
AHHHHH, FINALLY!! :D
today it's about LIPIDS!
so these are the key points:
1. Define & Classify lipids
2. Identify food sources & fuel value of lipids
3. Explain digestion, absorption & functions of lipids
4. Describe role of lipids & blood lipids in health
5. State dietary recommendations for lipids
6. Describe effects of over-consumption & deficiency of lipids
okay, so firstly - classification !
1. Simple Lipids - Tryglycerides
-predominant lipid in foods & body!
-3 molecules of fatty acids linked to 1 molecule of glycerol
-stored in body in fat cells (adipocytes) in adipose tissues
2. Compound Lipids
-Phospholipids (eg lecithin) soluble in both oils & water
-Lecithin widely used as emulsifier
-Lipoproteins - transport lipids within body
4 main types of Lipoproteins
1. Chylomicrons - synthesized in small intestine
2. VLDL (Very-low-density Lipoproteins)
3. LDL (Low-density Lipoproteins)
4. HDL (High-density Lipoproteins)
How VLDL becomes LDL
-VLDL gives away tryglycerides to cells while picking up cholesterol
-thus, LDL
LDL is known as the "bad cholesterol".
LDL increases, risk of heart attack die to narrowed blood vessel increases.
HOWEVER,
HDL reduce risks of heart disease.
It picks up cholesterol from other tissues to be transported back to liver for breakdown & excretion.
3. Derived Lipids
-Sterol (eg cholesterol)
sterols naturally found in plants called phytosterols
cholesterol - found in animals!
Steroid hormones
(cholesterol converted into steroid hormones)
-have steroid nucleus in their structure
4. Lipid Related Compounds - Fat soluble vitamins (A, D, E, K)
More About Fatty Acids
1. Short chain fatty acids (less than 6 carbons)
eg dairy fats: milk, butter
2. Medium chain fatty acids (6-10 carbons)
eg coconut oil
3. Long chain fatty acids (more than 12 carbons)
eg found in human cells
Saturated fats (animal fats) - solid
Polyunsaturated (vegetable oil) - liquid
HYDROGENATION
-chemical process by which hydrogens are added to a double bond in a monosaturated or polyunsaturated fatty acid
-reduces no of double bond - fat more resistant to oxidation
-hydrogenation makes a fat more saturated
there are:
Cis & Trans Fatty Acids
Replace saturated fat with monounsaturated/polyunsaturated fat!
lowers blood cholesterol levels & lowers LDL & lowers risk for atherosclerosis and heart disease
Recommended Intake
-30% oe lwaa od out total energy should be from lipids
-Linoleic acid (omega-6)- 5-10%
-Linolenic acid (omega-3)- 0.6-1.2%
Functions
1. A concentrated source of energy
2. Main resting muscle fuel
3. Emergency/reserve fuel
4. As padding to protect internal organs
5. Insulate body from extremes of temperature
6. Form major component of cell membranes
7. As raw materials to synthesize body compounds
8. As carriers
9. Support health
Excessive Intake
1. Cardiovascular disease
-increase dietary intake of total fats (esp sat n trans fats) & cholesterol increases risk of atherosclerosis
2. Certain cancers
-diets (rich in fats esp animal fats), increases risk of certain cancers
3. Obesity
AHHHHH, FINALLY!! :D
