chapter 5: lipids Flashcards
types of lipids
Fatty acids
triglycerides (3 fatty acids)
Phospholipids (2 fatty acids)
Cholesterol (no fatty acids)
why are lipids necessary?
- lipids enhance flavor
- enhance intestinal absorption of fat-soluble vitamins and phytochemical
–> we need at least 20g of fat to properly absorb fat soluble vitamins
- contribute to satiety (that feeling of fullness)
satiety
the feeling of fullness that occurs after a meal and inhibits eating until the next meal
–> determines how much time passes between meals
what type of tissue is fat
fat is a type of connective tissue that supports other tissues
what does visceral fat protect?
abdominal organs
what does subcutaneous fat do?
located below surface of the skin
helps maintain body heat and cushion body
true or false
fat provides a lot of energy
true
–> they provide two as much as carbs or proteins
only form of energy that is stored for prolonged periods of time
lipids
main source of energy when we are at rest
lipids
downside of fat storage
we can store an unlimited amount
can get fat cells to 1000 their original size
basically, we can get fat afff
basic building block of all acids
fatty acids
only fat molecule with no fatty acid
cholesterol
short chain fatty acids
2 to 4 carbons long
medium chain fatty acids
6 to 12 carbons long
long chain fatty acids
14 to 24 carbons long
fatty acid composition
chain of carbon atoms, bonded to hydrogen atoms
Contain a Methyl group, CH3 at the beginning
there is the acid end (COOH at the end)
why do some fatty acids have a bent chain?
because of double bonds
saturated acids
fatty acids with no double bonds
unsaturated acids
fatty acids with at least one double bond
monounsaturated fatty acid
fatty acids with one double bond
polyunsaturated fatty acid
fatty acids with more than one double bond
Omega-6 FA
18,2,w6
fatty acid with 18 carbon molecules and two double bonds
Omega-9 FA
18,1,w9
fatty acid with 18 carbon molecules and one double bond
which fatty acid is essential and we struggle to get in our diet?
omega 3
which fatty acid is essential and we easily get with our diet?
Omega-6
Fat cell – Adipose cell
Protects viscera and bones from breaking when we fall
Fat, like blood, is a type of connective tissue that supports other tissues
what does our body do with omega 6?
Our cells convert linoleic acid and Omega-6 to Arachidonic acid
–>necessary for synthesis of cell membrane
–> becomes a part of the phospholipids in cell membrane
omega 3
required in small amounts and few foods can supply it
three types of acids in omega 3 and the foods that we can get them from
- Lonolenic acid – walnuts
–> If your body has enough of this it can synthesize the other two
- DHA (Docosahexaenoic Acid) - fish and shellfish
- EPA (Eicosapentaenoic Acid) - fish and shellfish
DHA (Docosahexaenoic Acid)
Abundant in brain tissue
Essential for dev of the brain
Maintenance of normal brain functioning
Improves learning ability
Deficit is associated with impaired learning
EPA (Eicosapentaenoic Acid)
Lower blood pressure
Reduce blood clot formation
Protects against irregular heartbeat
Reduces inflammation
Reduce CVD
Trans fatty acids (TFA)
Can kill you
H atoms on either sides of the double bond on opposite sides of the chain
trans fats are manmade through a process of hydrogenation
–> unsaturated fatty acids are bombarded with H atoms
the carbon chain isn’t bent
–> fatty acids go from a Cis to a Trans configuration
–> the result is unsaturated FAs behaving like saturated FAs
Trans-fats are more resistant to rancidity, products made with trans fats have a longer shelf life (but contribute to coronary heart disease)
Cis-fatty acids
H atoms on either side of the double bond on same side of the chain
it makes the carbon chain bend
Most common lipid found in food
Triglycerides
Triglycerides
95% of fat we eat is in the form of triglycerides
99% of the fat in our bodies is stored in triglycerides
can have varying amounts of saturated, monounsaturated and polyunsaturated fatty acid chains but usually one predominates
Polyunsaturated fatty acids (PUFA) (omega 3 and 6)
acids with double bonds
Promote health when not deep fried
–> Oils with high amounts of PUFA turn rancid when deep fried (Rancid fat is unhealthy and has potential to damage DNA)
Polyunsaturated fatty acids (PUFA) when exposed to high heat
the double bonds in the fatty acid break
H atom is lost and the carbon atom now has an incomplete valence shell
–> Creating a free radical: atom with an incomplete valence shell
why are PUFAS more sensitive to heat?
due to their multiple double bonds in the Cis configuration
Phospholipids
Compund similar to a triglyceride but having a phosphate group (containing salt) and choline (or another nitrogen containing compound) instead of the fatty acids
–> 2 fatty acids
they have partial solubility
–> partly responsible for creation of life because they make up the cell membrane of all living organisms
the fatty acids of Phospholipids
diglycerides
–> attached to a glycerol mol
Most common phospholipid
Lecithin
lipid bi-layer
2 layers of phospholipids
–> face outwards towards the water to form Hydrogen bonds in and out of the cell
–> hydrophobic tails shy away intermingling and forming lipid bilayer
Arachidonic acid (Omega-6 fatty acid)
what is present in the body’s lipid bilayer
Diglycerides
Partly soluble
act as emulsifiers
emulsifiers
allow non-polar molecules, like lipids, to mix together with polar molecules without splitting
Cholesterol
found in animal kingdom (not in plant based)
–> eggs, dairy, meat, fish and poultry
not an essential nutrient, liver can synthesize it
lacks fatty acids and does not prod energy
cholesterol positive functions in the body
- Cell membrane are stubbed with cholesterol
- Necessary for synthesis of estrogen and testosterone
- Vitamin D synthesis
- Bile contains cholesterol and is crucial to digestion of lipids
role of the oral cavity with fats
warmth of your mouth melts some fat along with lingual lipase before reaching the stomach
role of the stomach with fats
they encounter gastric lipase
–> These two enzymes pull some of the fatty acids away from the triglycerides
role of the small intestine with fats
Bulk of chem digestion of lipids
–> done with accessory organs (liver, gallbladder, pancreas)
how do accessory organs know of the arrival of lipids?
Hormones
–> Epithelial cells in small intestine release hormones into blood stream via blood capillaries
role of the gallbladder with fats
squirts bile into the small intestine
role of bile with fats
Contains cholesterol, salts and lecithin
Breaks down the large lipid globules into smaller bits called micelles
Pancreatic lipase released into duodenum, breaks down the triglycerides into free fatty acids and monoglycerides
Absorption of shorts and medium chain fatty acids
cross into the epithelial cells
go out the other end
enter the blood capillary and bee line the liver, just like carbs
Lipoproteins
Contain: protein, triglycerides, cholesterol, phospholipids
Non-polar
Shell made of phospholipids facing outwards allowing lipoproteins to dissolve in water
4 types of lipoproteins
- Chylomicrons
- VLDL (Very low density lipoproteins)
- LDL (low density lipoprotein)
- HDL (high density lipoprotein)
Chylomicrons
transport dietary triglycerides and contain mostly triglycerides
VLDL (Very low density lipoproteins)
product of the liver
liver converts extra glucose to fatty acids packing them into VLDL for delivery to fat cells
mostly triglycerides but when they unload the triglycerides they are cholesterol rich leftovers called LDLs
LDL (low density lipoprotein)
mainly cholesterol and deliver cholesterol to cells (bad cholesterol)
HDL (high density lipoprotein)
synthesized in the liver
scavenge for cholesterol from dead and dying cells and return to the liver
Mainly protein (good cholesterol)
Cardiovascular disease (CVD)
Disease of the heart or blood vessels
CVD responsible for 25% of deaths in Canada, costs Canadian econ more than $18 bil/year
most common Cardiovascular disease (CVD)
Coronary heart disease
Path leading to CVD begins where?
with inflammation of the arterial wall
–> Excess LDL cholesterol or excess glucose cause irritation of blood vessels increasing the permeability of the arteries and elicits an inflammatory response from the immune system
–> cells fromimmune sys rush over to repair and pick up LDL cholesterol and harden in arteries (plaque) and they narrow
Heart attack
the death of cardiac muscle tissues resulting from blockage of one or more coronary arteries (which supply blood to cardiac muscles)
–> If there is build up in the artery, nutrients like oxygen are prevented from reaching the muscle cells that make up the heart tissue, cells die causing the heart to stop and gynopctorus is caused by partial blockage of the coronary arteries and results in chest pains
Stroke
death of nervous tissue in the brain, usually from rupture or blockage of arteries in the head
Reducing risks of CVD
- Increase soluble fiber intake
- Limit fat intake to AMDR (20-35% of cals should come from lipids)
- Increase omega-3 fatty acid intake
effects of an increase in soluble fiber intake to reduce risks of CVD
magic goo caries bile (which has cholesterol) for elimination to the large intestine
–> evacuates cholesterol
effects of an increase in soluble omega-3 fatty acid intake to reduce risks of CVD
Anti-inflammatory effect
trans fat not made by man
butter
a free radical (effect of deep frying)
atoms with incomplete valence shell
frying lipid created rancid lipids, which are free radicals
this is bad
the most common phospholipid
lecithin
key cholesterol functions
vitamin d synthesis
bile contains cholesterol, which is crucial for the digestion of lipids
