chap 6 Flashcards
types of lipids
fatty acid, triglycerides, phospholipids, cholesterol
lipids generally ____ in water
insoluble
fatty acids are ___ dense than water
less
major functions of lipids in the body
provide, store energy
maintain cell membrane
produce certain hormones
insulate and cushion the body
absorb and store fat-soluble vitamins and phytochemicals
contribute to foods
lipid contribution to food
rich flavor, smooth texture, appetizing aroma
fatty acid
contain hydrocarbon chain with an omega group (methyl, CH3) at one end, and an acid group (COOH) at the other
short chain fatty acid
2-4 carbon
medium chain fatty acid
6-12 carbon
long chain fatty acid
14-24 carbon
saturated fatty acid
each carbon atom is completely filled with hydrogen
unsaturated fatty acid
missing hydrogen atoms, molecule has one or more double bonds in the carbon chain
monounsaturated
only one double bond within the carbon chain
polyunsaturated
two or more double bonds within the chain
how to get omega number
count carbons from one omega end and the number is where the double bond occurs
difference between fats and oils
fats are solid at room temp and most oils are liquid
foods that are rich sources of long chain fatty acids tend to be more ____ at room temp than foods with larger amounts of unsaturated
solid
two essential fatty acids
omega-3 and omega-6
alpha-linoleic acid
omega 3
linoleic acid
omega-6
which omega essential fatty acid is not as prevalent
omega 3
DHA made from
omega 3, alpha-linoleic
EPA made from
omega 3, alpha-linoleic
arachidonic (AA) made from
linoleic acid, omega 6
fatty acid deficiency is uncommon in the US because
americans consume large amounts of fat
signs of essential fatty acid deficiency
scaly skin, hair loss, poor wound healing
infants with essential fatty acid deficiency experience
poor nervous system development, do not grow
trans fat
unsaturated fatty acids with the hydrogens of double bonded carbons on opposite sides of the molecule rather than the same side
few foods naturally contain trans fat
meat, some dairy
partial hydrogenation (PHOs)
food manufacturing process that added hydrogen atoms to some unsaturated fatty acids in a liquid vegetable oils
PHOs convert natural cis fatty acids to
trans fatty acids
PHO structure
similar to saturated
more solid at room temp
PHOs are ___likely to undergo oxidation
less
PHOs can cause
increase heart disease risk
the FDA determined PHOs are
dangerous, banned
triglyceride
3 fatty acids attached to a glycerol backbone
about 95% of lipids in the body and in foods are in the form of
triglycerides
saturated fat food sources
beef, butter, cream, whole and reduced-fat dairy, coconut
monounsaturated fat food sources
avocados, olives, peanuts, pumpkin and sesame seeds, almonds, hazelnuts, pecans, fish
polyunsaturated fat food sources
walnuts, flaxseed, fish
trans fat food sources
beef, milk, other dairy
phospholipids are chemically similar to triglyceride except
one fatty acid is replaced by a compound that contains phosphorus and often nitrogen
phospholipids contains ____ tail and ____ head
hydrophobic, hydrophilic
phospholipids found naturally in
plant and animal foods
major phospholipid in food
lecithin
rich sources of lecithin
egg yolk, liver, wheat germ, peanut butter, soybean
lecithin contains ____
choline
choline
compound that nerves use to produce acetylcholine
eggs are often used in cooking for their
emulsifying ability
phospholipids act as emulsifiers because of
hydrophobic and hydrophilic ends
emulsifiers
substances that keep water soluble and water insoluble compounds mixed together
___ foods often have emulsifying agents added
processed
lipid major structural component of cell membrane
double layer of phospholipids allows membrane flexibility
sterol
carbons arranged in rings, which makes them a more chemically complex type of liquid than a triglyceride or phospholipid
most known sterol
cholesterol
cholesterol only found in
animal foods
common sources of cholesterol
egg yolk, liver, meat, poultry, whole mill, cheese, ice cream
the body produces and uses cholesterol to make
vitamin d
steroid hormones
bile
plant sterol and stanols are not ____ by humans
absorbed
plant sterol and stanols compete with ____ for absorption
cholesterol
how are blood cholesterol levels decreased with plant sterols and stanols
they compete with each other and the plant sterol and stanols will be absorbed more than the cholesterol
best sources of plant sterol/stanols
nuts, seeds, legumes
some fat digestion occurs due to the action of
salivary lipase and gastric lipase
primary site of lipid digestion
small intestine
fatty chyme in the small intestine stimulates release of
cholecystokinin (CCK)
CCK signals the gallbladder to
release bile
CCK stimulates the pancreas to
release digestive enzymes, including pancreatic lipase
bile contains ____ which aid in digestion and absorption
bile salts
bile salts have ____ heads and ____ tails and surround lipid particles to form ____
hydrophilic, hydrophobic, micelles
micelles
transport lipids to absorptive cells
action of bile salts increase the surface area of lipids available to
pancreatic lipase, aids in digestion
pancreatic lipase
removes two fatty acids from a triglyceride, forming a monoglyceride, also produces some FFA and glycerol
phospholipids digested by
phospholipase, removes two FA
cholesterol does not undergo
digestion
end product of lipid digestion
glycerol, FFA, monoglycerides, phospholipid fragments
lipid absorption: micelles transport end products of lipid digestion to the villi in the ____
small intestine
short and medium chain fatty acids directly enter the
portal bloodstream
absorptive cells of the small intestine form ____ with other end products of lipid digestion
chylomicrons
chylomicrons
lipoproteins
lipoprotein
water soluble structures that transport lipids through the bloodstream
chylomicrons travel through the ___ system to the thoracic duct where they enter the blood stream
lymphatic
lipoprotein lipase
enzyme capillary walls that break down triglyceride from chylomicrons as they move into the body
stomach lipid digestion/absorption
minor digestion of fat by salivary and gastric lipases
liver lipid digestion/absorption
liver produces bile, which is stored in the gallbladder and released into small intestine. bile aids in lipid digestion and absorption by emulsifying lipids in digestive juices
pancreas lipid digestion/absorption
secretes a mixture of enzymes, including pancreatic lipase into sm intestine
small intestine lipid digestion/absorption
primary site
____% of undigested fat is normally excreted in the feces
<5
most used bile salts are absorbed in the
small intestine ileum
the liver recycles used bile salts to make
new bile
eating food that contains ___ fiber can interfere with bile salt recycling
soluble
without a supply of recycled bile salt
the liver has to remove cholesterol from the bloodstream to make new bile salts, blood cholesterol levels drop
adipose cells remove ___ and ___ from circulation and reassemble into ____ for storage
glycerol, FFA, triglycerides
cells remove ____ from the bloodstream and metabolic them for energy
Fatty acids
liver removes ____ molecules and converts them to ____
glycerol, glucose
AMDR for fat
20-35%
saturated fat should be ___%
<10
lipid information required on label
total fat
sat fat
trans fat
cholesterol
CVD
group of medical conditions that affect the functioning of the heart and blood vessels
coronary artery disease
affects the arteries that supply the heart, often leading to heart attack
cardiovascular diseases
CAD, PAD, stroke, hypertension
____ and ___ are among the top 5 leading causes of death
CAD, stroke
atherosclerosis
long term disease process in which plaque builds up inside arteries
atherosclerosis initiated by
excess cholesterol or glucose in the bloodstream, compounds from smoke, bacteria
atherosclerosis leads to formation of
arterial plaque
arterial plaque may result in the formation of
thrombus
thrombus
fixed bunch of blood clots that remain in place and disrupt flood flow
a healthy artery has ___ lining
smooth
when the lining of the artery become irritated, certain cells within the wall deposit _____ and other substances under the lining to repair damage
cholesterol
plaque ___ and ___ the normally smooth surface, which ___ blood flow, making ___ more likely to form ____
narrows, roughens, slows, clots
if a clot lodges on the plaque and becomes wedged,
blood flow can become blocked completely
embolus
thrombus or part of a plaque that breaks free and travels through the bloodstream
a thrombus or embolus can completely block flood flow leading to
heart attack
stroke
gangrene
atherosclerosis in the carotid artery in the neck can
increase risk for stroke
atherosclerosis and hypertension
affected arteries thicken and lose flexibility
lipoproteins transport
lipids in the blood
lipoproteins play a major role in
the development of atherosclerosis
4 major types of lipoproteins
VLDL, HDL, LDL, chylomicron
____ content contributes to the density of a lipoprotein
protein
chylomicron ___% protein
1-2
HDL ___% protein
45-60
LDL ___% protein
25
VLDL ___% protein
5-10
HDL
good cholesterol
HDL transports cholesterol ____ tissues and ___ liver, where it can be eliminated ______ contribute to plaque formation
away, to, does not
LDL
bad cholesterol
LDL carries cholesterol ___ tissues, _____contribute to plaque formation
to, does
VLDL carries much of the ____ in the bloodstream
triglycerides
high levels of VLDL may contribute to
atherosclerosis
major risk factors for atherosclerosis
age, genetics
unhealthy diet, HTN, diabetes, elevated cholesterol (LDL), excess body fat, physical inactivity, tobacco use
when we absorb fat where does it go
lacteals/lymphatic system
