Lecture 6: Lipids Flashcards
Saturated Fatty Acid structure component
-single carbon bonds
-packs together
-solid at room temperature
Unsaturated Fatty Acid structure component
-One or more double carbon bonds, fewer hydrogens
-don’t pack together
-liquid at room temperature
Monounsaturated Fatty Acid structure component
one double carbon bond
Polyunsaturated Fatty acid structure component
Two or more double carbon bond
Methyl group
“Omega end” -CH3
3 carbons away from double bond
(omega-3 fatty acid)
6 carbons away from double bond (omega-6 fatty acid)
Omega-3
-Reduces inflammation, blood pressure & clotting
-a-linolenic acid (18 carbon)
-Eicosapentaenoic acid (EPA), (20 carbon)
Dietary source of Omega-3
Fish oils
Omega-6
-Linoleic acid (18 carbons)
-polyunsaturated
-increases inflammation, blood pressure and blood clotting
Dietary sources of Omega-6
vegetable oils, meats
Essential fatty acids
A-linoleic & linoleic
Hydrogenation
H atoms are added to unsaturated fatty acids (cis) and create trans fatty acids.
Makes oils more solid (saturated)
reduces oxidation, rancidity and increases risk of CVD
CIS oleic acid (unsaturated fatty acid)
two functional groups on same side of the fatty acid chain
bends, does not pack tightly together
Trans oleic acid (unsaturated fatty acid)
Functional groups on opposite sides of the double bond
chain is straight, easier to pack
Carboxyl end
-COOH
Types of lipids
Triglycerides (95%)
sterols (3%)
Phospholipids (2%)
Triglycerides function
-control the body’s internal climate
-help the body produce & regulate hormones
-main form of lipid in the body
Leptin
Adipose tissues secretes this hormone, which regulates appetite
Triglyceride structure
Glycerol joined by three fatty acids that consist of carboxylic acid (-COOH) and methyl group (-CH3)
How do fatty acids differ
carbon chain length, degree of saturation
how are fatty acids held together
carbon atoms attached to hydrogen atoms
What fatty acid is essential for normal cell development and healthy skin?
polyunsaturated and monounsaturated
Phospholipid structure components
-glycerol head/backbone containing phosphate group and nitrogen (hydrophilic)
-two fatty acid chains (hydrophobic)
Phospholipids
essential components of cell membranes
Most well-known sterol
cholesterol
Sterol
complex molecules that contain interlocking rings of carbon atoms with side chains of carbo, hydrogen and oxygen
cholesterol functions
hormone functions, vitamin D synthesis
Do we need cholesterol in our diet, why or why not
No, our body naturally produces cholesterol. There are no benefits and should be limited to 300mg/day
What enzyme breaks down fat
Pancreatic lipase
Pancreatic lipase
breaks down triglycerides into monoglycerides, fatty acids and glycerol
Micelle
Transports lipids to SI surface for absorption
carriers that transport the hydrophobic lipids (such as triglycerides, cholesterol, and fat-soluble vitamins) to the surface of the intestinal epithelial cells (mucosal cells)
Mucosal cells
Breaks down fat into glycerol, monoglycerides and fatty acids
the absorbed lipids are reassembled into triglycerides and packaged into chylomicrons within the mucosal cells
Chylomicrons
lipid transport particle, enters lymph vessel
Lipoproteins
Chylomicron, VLDL, LDL, HDL
VLDL
formed by the liver after chylomicron delivers it’s content to the liver
LDL
formed when VLDL loses triglycerides
delivers cholesterol to cells
HDL
collects cholesterol from the cells back to the liver
Eicosanoids
made of 20-carbon polyunsaturated fatty acid
roles of lipids in health
energy storage
insulation & protection
hormone production
absorption of fat-soluble vitamins
atherosclerosis
arteries become stiffer and plaque filled, lesion in heart artery
AMDR for fat
20-35%
AMDR for essential fatty acids
linoleic: 5-10%
a-linoleic: 0.5-1.2%
dietary components of monounsaturated and polyunsaturated fats
olive oil, avocados, nuts, seeds, fatty fish
unhealthy fats
saturated or trans fat
healthy fats
unsaturated
Where does lipid absorption take place?
Blood vessels and lymphatic system
Adipose Tissue
How the body stores excess energy from food
What reduces LDL and increases HDL
trans fat
What should you add to rice to consume the essential amino acids? Broccoli or lentils?
Lentils
Micelle structure function
fatty acid core with water-soluble exterior allowing efficient transportation to intestinal microvillus
What are lipoproteins primarily made up of
triglycerides and cholesterol
what dietary components decrease blood cholesterol
soluble Fiber
fatty fish, nuts, olive oil
moderating alcohol intake
dietary sources of saturated
some meat, whole-sat dairy products and topical oils
dietary sources of trans fat
processed cookies, pastries, friend food, margarines
eicosanoids primary function
regulate inflammation
health affects of trans fat
inflammation, cvd risk
dietary-fat substitutes
carbohydrate-based replaces, can also be made from proteins (egg white, milk whey), not very stable can affected by temperature changes
food labels and trans fat
allow foods containing trans fat to be labeled “trans-fat free” if there are fewer than 0.5 grams per serving
what does cooking in vegetable oil refer to
hydrogenated vegetable oil: trans fat
risk factors for disease
high bp, high cholesterol, smoking, diabetes, poor diet
What does high LDL and low blood HDL indicate
blood cholesterol risk
what can a buildup of cholesterol in the blood lead to?
brittle blood vessels and blockage of flow
Lipid healthy diet includes:
choosing unsaturated fats, limiting saturated fat intake, low fat does not equal healthy, consume omega-3 daily, a “better fat” diet will support weight loss
