Flashcards in Nutrition Chapter 6 Deck (33):
What are the three types of lipids?
What are triglycerides?
the most common type of lipid found in food and the body (95%)
3 fatty acids bonded to a glycerol
What is esterification?
the processing of attaching fatty acids to glycerol (releases an H20 for each bond)
What is de-esterification?
the release of fatty acids from glycerol
What is re-esterification?
the process of reattaching a fatty acid to a glycerol that has lost a fatty acid
What is the structure of a fatty acid?
long chain of carbon atoms surrounding by hydrogen (4-24 carbons)
have an acid (carboxyl) group on one end and a methyl group on the opposite end
differ in number of carbons, saturation of hydrogen, and shape of the chain
What is hydrogenation?
The addition of hydrogen to a fatty acid's carbon chain. Can create trans fats when the hydrogens are on the opposite side of the double bond.
What are the essential fatty acids?
alpha-linolenic (the major omega 3) and alpha-linoleic (the major omega 6)
must get them from the diet, the body can't synthesize them (9th carbon from the omega end is the first place they can synthesize)
What is the structure of unsaturated fats?
has a double carbon bond which can cause it to kink
What is the structure of saturated fats?
have no double carbon bonds, each carbon has a hydrogen, straight chain, solid at room temp
What is the structure of polyunsaturated fats?
has more than one double carbon bond which can cause it to kink
What are the functions of triglycerides?
provide compact energy storage
insulate and cushion vital organs
help transport essential nutrients in the bloodstream
What are phospholipids?
A type of lipid with a phosphate compound (a glycerol, two fatty acids, phosphate group). The phosphate allows them to function in a watery environment without clumping together.
What are the functions of phospholipids?
component of a cell membrane (allows it to remain fluid)
What are sterols?
A lipid and a type of steroid. Arranged in many rings.
What are the functions of sterols?
make hormones (estrogen, testosterone, progesteron, cortisol)
forms cell membranes and allows fat-soluble substances to move into and out of the cell
form shell covering of chylomicrons
What are eicosanoids?
hormone like compounds made from essential fatty acids
regulate blood pressure, blood clotting, reproduction and immune and inflammatory responses
What are EPA and DHA?
long chain essential fatty acids
can be made from alpha-linolinec or found in some foods (fish)
not efficiently made in the body because omega 6s and omega 3s compete for the same enzymes
How is fat digested?
mainly in the small intestine, the presence of fat signals CCK hormone to have the pancreas release bile
fat is emulsified until it becomes micelles and can be absorbed
How is fat absorbed?
it is absorbed across the lining of the cell, reassembled into triglycerides and packaged into chylomicrons, get smaller and smaller until they can enter the blood stream via lymph and end up in the liver where they are chylomicron remnants
What are lipoproteins?
chylomicrons, VLDL, LDL, HDL
all made of phospholipid, protein, cholesterol, triglyceride in different proportions
transport cholesterol and triglycerides throughout the body
What are chylomicrons?
transport from the SI to the liver, delivering tris
remnant ends up in liver where fats are repackaged for delivery
What are VLDL?
very low density lipoproteins
largely triglycerides and cholesterol
start in the liver and transport tris to cells the chylomicron couldn't reach
What are LDL?
low density lipoproteins
transformed from VLDLs and they get smaller
What are HDL?
high density lipoproteins
start in many parts of the body
picks up cholesterol from dead cells and brings it back to the liver
What is the LDL receptor pathway?
how LDL is taken up by liver cells when the diet is low in sat. fat and cholesterol
What is the LDL scavenger pathway?
operates when the diet is high in sat. fat and cholesterol; reduces the liver's ability to remove LDL from blood via the receptor pathway
LDL removed via WBCs, oxidized and deposited in artery walls
What are the recommended intakes for fats?
No RDA, 20-35% of kcal
sat. fat less than 10% of kcal
cholesterol less than 300mg/day
AI for infants, omega-3 (1.6g men and 1.1g women) and omega-6 (17g men, 12g women)
What are the health effects of lipids?
some may promote cancer (prostate, maybe breast), over-consumption promotes obesity and CVD, diabetes, HTN
What are the health effects of omega-3s?
regular consumption can lower cholesterol and heart disease, prevents blood clots, lowers blood pressure, reduces blood tris, protects against arrhythmia, reduces inflammation
What role do fats play in heart disease?
excess fat and cholesterol increase risk
sat. fats stimulate production of cholesterol
What is the Hegstead equation?
change in total chol. = 2.01(change in SFA) - 1.01(change in PUFA) + .03(change in C)