Nutrition Chapter 6

Question 1

What are the three types of lipids?

Answer 1

triglycerides
phospholipids
sterols

Question 2

What are triglycerides?

Answer 2

the most common type of lipid found in food and the body (95%)
3 fatty acids bonded to a glycerol

Question 3

What is esterification?

Answer 3

the processing of attaching fatty acids to glycerol (releases an H20 for each bond)

Question 4

What is de-esterification?

Answer 4

the release of fatty acids from glycerol

Question 5

What is re-esterification?

Answer 5

the process of reattaching a fatty acid to a glycerol that has lost a fatty acid

Question 6

What is the structure of a fatty acid?

Answer 6

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

Question 7

What is hydrogenation?

Answer 7

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.

Question 8

What are the essential fatty acids?

Answer 8

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)

Question 9

What is the structure of unsaturated fats?

Answer 9

has a double carbon bond which can cause it to kink

Question 10

What is the structure of saturated fats?

Answer 10

have no double carbon bonds, each carbon has a hydrogen, straight chain, solid at room temp

Question 11

What is the structure of polyunsaturated fats?

Answer 11

has more than one double carbon bond which can cause it to kink

Question 12

What are the functions of triglycerides?

Answer 12

provide energy
provide compact energy storage
insulate and cushion vital organs
help transport essential nutrients in the bloodstream

Question 13

What are phospholipids?

Answer 13

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.

Question 14

What are the functions of phospholipids?

Answer 14

component of a cell membrane (allows it to remain fluid)

emulsifier

Question 15

What are sterols?

Answer 15

A lipid and a type of steroid. Arranged in many rings.

Question 16

What are the functions of sterols?

Answer 16

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

Question 17

What are eicosanoids?

Answer 17

hormone like compounds made from essential fatty acids

regulate blood pressure, blood clotting, reproduction and immune and inflammatory responses

Question 18

What are EPA and DHA?

Answer 18

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

Question 19

How is fat digested?

Answer 19

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

Question 20

How is fat absorbed?

Answer 20

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

Question 21

What are lipoproteins?

Answer 21

chylomicrons, VLDL, LDL, HDL
all made of phospholipid, protein, cholesterol, triglyceride in different proportions
transport cholesterol and triglycerides throughout the body

Question 22

What are chylomicrons?

Answer 22

largest lipoprotein
mostly triglycerides
transport from the SI to the liver, delivering tris
remnant ends up in liver where fats are repackaged for delivery

Question 23

What are VLDL?

Answer 23

very low density lipoproteins
largely triglycerides and cholesterol
start in the liver and transport tris to cells the chylomicron couldn’t reach

Question 24

What are LDL?

Answer 24

low density lipoproteins
mostly cholesterol
transformed from VLDLs and they get smaller

Question 25

What are HDL?

Answer 25

high density lipoproteins
mostly protein
start in many parts of the body
picks up cholesterol from dead cells and brings it back to the liver

Question 26

What is the LDL receptor pathway?

Answer 26

how LDL is taken up by liver cells when the diet is low in sat. fat and cholesterol

Question 27

What is the LDL scavenger pathway?

Answer 27

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

Question 28

What are the recommended intakes for fats?

Answer 28

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)

Question 29

What are the health effects of lipids?

Answer 29

some may promote cancer (prostate, maybe breast), over-consumption promotes obesity and CVD, diabetes, HTN

Question 30

What are the health effects of omega-3s?

Answer 30

regular consumption can lower cholesterol and heart disease, prevents blood clots, lowers blood pressure, reduces blood tris, protects against arrhythmia, reduces inflammation

Question 31

What role do fats play in heart disease?

Answer 31

excess fat and cholesterol increase risk

sat. fats stimulate production of cholesterol

Question 32

What is the Hegstead equation?

Answer 32

change in total chol. = 2.01(change in SFA) - 1.01(change in PUFA) + .03(change in C)

Question 33

How do the different lipids effect blood lipids?

Answer 33

Sat. Fat - raises LDL
PUFA - lowers LDL, lower HDL
MUFA - lower LDL, raises HDL
Trans - raises LDL, lowers HDL