Module 5: Lipids Flashcards
what is the scientific term for fats
lipids
define lipids
substances that are soluble in organic solvents (ether, acetone, chloroform)
what are the 3 major categories of lipids
- triglycerides
- phospholipids
- sterols
what elements compose lipids
- carbon
- hydrogen
- oxygen
what is the different between the composition of lipids and carbohydrates
- lipids have twice as many hydrogens
- lipids cannot be polymerized; they can only make up to triglycerides
define fatty acid
chain of carbons linked together
what are the two groups on the ends of a fatty acid
- carboxyl group (COOH)
- methyl group (CH3)
describe the methyl group on a fatty acid
- hydrophobic
- tail end
describe the carboxyl group on a fatty acid
- hydrophilic
- head end
what types of lipids are composed of fatty acids
- phospholipids
- triglycerides
describe saturated fatty acids
- carbon chain is fully occupied by hydrogen atoms
- no double bonds
- solid at room temperature
describe unsaturated fatty acids
- fatty acids with one or more double bonds
- monounsaturated or polyunsaturated
- liquid at room temperature
what are examples of sources of saturated fats
- animal proteins
- red meat, dairy, lard, bacon fat
why are saturated fats considered bad
large amounts cause metabolic stress and dysregulation
define essential fatty acids
- cannot be made by the body
- must be obtained through diet
what are the two essential fatty acids
- omega 6
- omega 3
what is the parent omega 6 fatty acid
linoleic acid
what is the parent omega 3 fatty acid
linolenic acid (aka: alpha LA, ALA)
what are the benefits of omega 3 fatty acids
- improves insulin sensitivity
- needed for brain function
- cellular repair after damage
- beta oxidation (fat burning)
- blocking inflammation
- prevents heart disease and blood clot formation
describe what the omega 6 fatty acid arachidonic acid does
can go down the COX metabolic pathway that produces inflammation in tissues
which type of essential fatty acid do we typically not get enough of
omega 6
what is the actual ratio of omega 6 to omega 3 that we consume vs the ideal
- actual: 10:1
- ideal: 4:1
what types of omega 3 fatty acids can be made from ALA
- EPA
- DHA
what is the more bio functional form of omega 3 fatty acids
DHA
what are the benefits of omega 6 fatty acids
- incorporated into cell membranes
- precursors to compounds involved in reproduction and blood flow
why are omega 6 and 3 fatty acids named the way they are
- omega 6 fatty acids have a double bond on the 6 carbon from the omega end
- omega 3 fatty acids have a double bond on the 3 carbon from the omega end
what group is the omega and alpha end of fatty acids
- omega end: methyl group, hydrophobic
- alpha end: carboxyl group, hydrophilic
what are sources of EPA and DHA
- cold water fish
- breast milk
what is hydrogenation
- process of adding hydrogens to unsaturated fats
- makes them sold at room temperature
describe trans fats
- made from hydrogenation
- hydrogens on opposite sides of the double bond
where are there small amounts of naturally occuring trans fats
- dairy milk
- meat
how do trans fats and cis fats differ
- trans fats: hydrogens are on opposite sides of the double bond giving them a straighter form
- cis fats: hydrogens are on the same side of the double bond giving them a more curved form
how do trans fats affect cholesterol
- increase LDL (bad cholesterol)
- decrease HDL (good cholesterol)
describe low density lipoproteins (LDL)
- bad form of cholesterol
- have a small amount of fatty acids and cholesterol
describe high density lipoproteins (HDL)
- good form of cholesterol
- pick up excess cholesterol
what do both LDL and HDL start off as
very low density lipoproteins (VLDL) in the liver
how much trans fatty acids per day does the AHA recommend
- 2g a day or less
- less than 1% of your total calories
what is a triglyceride composed of
- 3 carbon glycerol backbone
- 3 fatty acids
what is the primary form of lipid found in the body
triglycerides
what do the triglycerides found in your body reflect
dietary fatty acids consumed
which fatty acid end group is connected to the glycerol backbone
carboxyl group
what is the composition of phospholipids
- 3 carbon glycerol backbone
- 2 fatty acids
- one phosphate group
what is the purpose of phospholipids in the body
assist the body in transporting fat through watery substances (emulsification)
which part of a phospholipid is hydrophilic
phosphate head
which part of a phospholipid is hydrophobic
fatty acid tail
what are phospholipids important components of in the body
- cell membranes and organelle membranes
- lipoproteins
what are lipoproteins
- spheres made of phospholipids which protect the contents of the lipoprotein
- transport particles of fats throughout the body
what are examples of lipoproteins
- chylomicron
- LDL
- HDL
where is chylomicron made
enterocytes in the distal ileum
what is the largest lipoprotein in the body
chylomicron
what is the structure of sterols/cholesterol
four-ringed structure
what does cholesterol make
- hormones like testosterone and estrogen
- vitamin D
which cells in the body can make cholesterol
all cells
which organ makes most of the cholesterol in the body
liver makes 40%
what is the purpose of cholesterol in cell membranes
structural integrity and rigidity
is vitamin D a vitamin or a hormone
both
explain how we get vitamin D from sunlight
- sunlight hits cholesterol in the cell membranes of our skin cells
- moves to the liver and then to the kidneys to make vitamin D
is cholesterol essential or not essential
- not essential
- the body can make it; not needed in diet
what happens if you eat excess cholesterol
- body absorbs less
- liver makes less
how much cholesterol should be consumed per day according to the AHA
below 300mg a day
how does cholesterol contribute to heart disease and atherosclerosis
- excess cholesterol is absorbed through endothelial cells in blood vessels and deposited on the other side of the vessel wall
- the cholesterol builds up and presses on the vessel causing it to narrow
what are the functions of lipids in the body
- flavor and satiety
- storage of energy as fat tissue
- hormone production
- absorption of fat-soluble vitamins
- cell membrane structure
- orang protection
- heart protection from fatty acids
what is the primary energy source for the heart
lipids
how many kcal/g does fat provide
9 kcal/g
what are the two essential fatty acids
- linoleic acid (omega 6)
- linolenic acid (omega 3)
what can omega 3 and 6 fatty acids do as eicosanoids
- relax blood vessels
- promote clotting
what are the fat-soluble vitamins
K, A, D, E
what is different in regards to lipids between men and women
- % body fat
- women have greater % body fat than men
what nutrient provides the greatest level of satiety
protein
how does eating fats affect digestion
- slows stomach emptying
- duodenum senses fats and sends signals to pyloric sphincter
- makes you feel full longer
what are sources of cholesterol
animal products
describe carbohydrate-based fat mimetics
- add creaminess and moistness
- maltodextrins, cellulose, gums
- 1-4 kcal/g
describe protein-based fat mimetics
- denature under high heat
- used in frozen desserts
- 4 kcal/g
describe fat-based fat substitutes
- non-digestible or partially digestible
- contribute to taste, texture, and mouthfeel
- olestra, salatrim, caprenin
what are side effects of fat-based fat substitutes
- reduced vitamin A, D, E, and K absorption
- loose stools
- abdominal cramps
how do some marketed weight loss drugs work
inhibit the digestive enzyme that breaks down triglycerides
what are side effects of weight loss drugs
- anal leakage
- reduced fat soluble vitamin absorption
- malabsorption of oral contraceptives (cholesterol based hormones)
what is the leading cause of death in the US
heart disease
what are modifiable risk factors of heart disease
- high blood pressure
- high cholesterol
- smoking
- diabetes
- poor diet and physical inactivity
- overweight and obese
what nutrients can raise the risk of heart disease if overconsumed
- total fat
- saturated fat
- trans fat
what is the first form of lipoprotein made in the liver
very low density lipoprotein (VLDL)
what is VLDL composed of
- triglycerides
- cholesterol
what does VLDL become as it drops triglycerides to body tissues
- VLDL
- IDL
- LDL
why is LDL bad
- composed of mainly cholesterol
- drops excess cholesterol causing problems
why is HDL good
- picks up excess cholesterol
- takes it to the liver for recycling or for bile
- also takes it to the ovaries or testes for hormones
what does chylomicron distribute
dietary fats
what type of fats does VLDL, IDL, and LDL distribute
- endogenous fats
- fats made from other nutrients (carbs, proteins)
what is the primary type of heart disease linked with fat intake
atherosclerosis
define atherosclerosis
- buildup of fatty deposits in arteries
- reduces blood flow to the heart causing ischemia
- artery becomes blocked causing myocardial infarction
- can cause stroke if artery blocked is supplying blood to the brain
what vessel is responsible for most lethal myocardial infarctions
left anterior descending artery
what is the purpose of proteins on the outside of lipoproteins
markers to tell the liver what to do with it
what is the AMDR for fat
20-35%
what is the AMDR for fat for children under 2
30-35%
why do children have a greater AMDR for fats
needed for growth and nervous system development
what percent of total calories should be saturated fats
less than 10%
how much exercise should you get each week
- 150 minutes of moderate activity
- 75 minutes of vigorous activity
how many alcoholic drinks should men and women consume a day
- men: 1-2
- women: 1
why does the mediterranean diet include wine
wine has lots of phytochemicals
what has happened to the % of calories from fats in the US over the last 2 decades
decreased
is there conclusive evidence relating diets high in fat to cancer
no
what can influence cancer risk
type of fatty acid consumed
what fats increase cancer risk
saturated fats
what fats decrease cancer risk
fish high in omega 3 fatty acids
