Chapter 6 - Lipids Flashcards
What is meant by “lipid”?
Chemical term for fat and oil
What are the families of lipids?
triglycerides
phospholipids
sterols
What is the energy yield of fat?
9 Cals/gram
What percentage of energy comes from fat in the typical American diet?
34%
What is hidden fat?
not seen
saturated and unsaturated fats
What is visible fat?
easily seen
butters and oil pockets in salad dressing
What is the chemical makeup of triglycerides?
3 fatty acids attached to a glycerol backbone
What reaction releases fatty acids from glycerol?
hydrolysis
How many carbons do short-chain fatty acids have?
6 or fewer
At colder temperatures, what state do short-chain fatty acids stay in?
liquid
How many carbons do medium-chain fatty acids have?
6-12
What happens to medium-chain fatty acids at room temperature and cooler temperatures?
liquid at room temperature
solid when chilled
How many carbons are in long-chain fatty acids?
12 or more
At room temperature, what state are long-chain fatty acids in?
solid
What makes a fatty acid saturated?
hydrocarbon chain is saturated with hydrogen
What state are saturated fats in at room temperature?
solid
What is the relationship between rancidity and saturated fatty acids?
saturated fatty acids are more resistant to rancidity
What is another name for rancidity?
oxidation
oxidative damage
Where are saturated fatty acids found?
animal fats
tropical oils
What makes a fatty acid unsaturated?
hydrocarbon chain is not saturated with hydrogen
Why are unsaturated fatty acids bent?
they contain at least one double bond between the carbon atoms
What is the relationship between unsaturated fats and rancidity?
unsaturated fats are less resistant to rancidity
What oils contain unsaturated fatty acids?
plant oils
How to trans fats form?
via hydrogenation to artificially saturate oils
What happens to trans fats in our body?
deposited in our arteries because we don’t have enzymes to deal with trans-bonds
What kind of cholesterol is bad?
LDL
What kind of cholesterol is good?
HDL
Why do we use trans fats?
to increase shelf-life
What are the functions of triglycerides?
- concentrated source of energy
- main fuel source for all cells except nervous system and RBCs
- insulate and cushion organs
- help absorb and transport fat-soluble vitamins
Why are omegas essential?
your body needs them but can’t make them
What are omega-3’s?
alpha-linoleic acid
What do omega-3’s make?
EPA and DHA
Where are omega-3’s found?
sea foods
nuts
seeds
What are omega-6’s?
linoleic acid
What do omega-6’s make?
arachidonic acid
Where are omega-6’s found?
animal protein and veggie oils
What is the main function of omegas?
make eicosanoids
What are eicosanoids?
like hormones, but aren’t hormones
- work locally
- effective in small doses
- aren’t made without omegas
What is the recommended omega-6 to omega-3 ratio?
5:1 to 10:1
What is the Western diet’s omega ratio?
15:1 to 17:1
What properties do omega-3’s present?
anti-inflammatory properties
What properties do omega-6’s present?
pro-inflammatory properties
What do epidemiological studies observe?
patterns
What do dietary intervention studies observe?
cause and effect
purposefully change diet
What are the function of eicosanoids?
- regulate cell division rates
- maintain normal kidney function and fluid balance
- directing hormones to target cells
- regulate flow of substances in and out of cells
- regulate ovulation, body temp, immune system function, hormone synthesis
When is DHA needed?
fetal life
infancy
What is DHA needed for?
- normal development and function of retinas
- normal development and maturation of nervous system
What are phospholipids?
lipids attached to phosphate group
What is the major class of phospholipids?
phosphoglycerides
What are the functions of phospholipids?
- act as emulsifier
- lipid bilayer in cell membranes
Are phospholipids essential or nonessential?
nonessential
liver makes them
What is the structure of sterols?
carbons arranged in multi-ringed structures
Cholesterol is used to make what?
- sex hormones
- active form of vitamin D
- adrenal hormones
- bile
- cell membranes
What organ makes cholesterol?
liver
How much lipid digestion and absorption occurs in the mouth?
a little
What allows for lipid digestion and absorption in the mouth?
lingual lipase
How much lipid digestion/absorption happens in the stomach, and what allows for it?
a little
gastric lipase
How much lipid digestion/absorption happens in the small intestine, and what does it trigger?
a lot
release of CCK
What emulsifies fat?
bile
What does bile break fat down into?
micelles
What do micelles do for lipid digestion and absorption?
increases the surface area
allows pancreatic lipase to break down triglycerides to free fatty acids and monoglycerides
Where does lipid absorption occur?
by brush border of enterocytes
What determines where fatty acids are absorbed into?
carbon chain length
Where are short and medium-chain fatty acids absorbed?
cardiovascular system
portal vein
liver
Where are long-chain fatty acids absorbed?
lymphatic system
How is fat removed from the small intestine?
lipoproteins
What do lipoproteins do?
transport lipids all around the body
What are the four major types of lipoproteins?
chylomicrons
VLDL
LDL
HDL
Where are chylomicrons made?
intestinal cells
What are chylomicrons made up of?
triglycerides
What do chylomicrons do?
- transport lipids from intestines to lymph circulation
- deposit triglycerides to skeletal muscle and adipose tissue
What happens to chylomicrons as fat is pulled out over time?
shrink over time
Where do chylomicrons end up?
liver
What does VLDL stand for?
Very-low-density lipoproteins
What is the function of VLDL?
transport lipids from liver to tissues
Where do VLDLs start?
liver
after consuming saturated fats
What are VLDLs made of?
triglycerides
Where do VLDLs end?
circulation
What does LDL stand for?
low-density lipoproteins
What is the function of LDL?
deliver cholesterol to tissues
Where does LDL start?
not made anywhere
VLDL is turned into LDL
What is LDL made up of?
cholesterol
Where does LDL end?
liver for decontruction
or
deposits in the arteries
What does HDL stand for?
high-density lipoproteins
What is the function of HDL?
artery scrubber
picks up cholesterol and returns it to liver
Where does HDL start?
liver
after consuming unsaturated fats
What are HDLs made up of?
45-50% protein
Where does HDL end?
returns cholesterol to liver
85.6 million Americans suffer from some form of what?
cardiovascular disease
What is atherosclerosis?
disease in which lipids and fibrous materials are deposited in artery walls
What is the number one prescribed drug of all time?
lipitor
How do you decrease your risk of CVD?
- increase poly and mono-unsaturated fat intake
- increase plant food intake
- B-vitamins
- antioxidants
- moderate alcohol consumption
- whole foods
How do you increase your risk of CVD?
- saturated fat
- trans fat
- sodium
- excess sugar
