Unit 3 - Lipids Flashcards
what are lipids? what are they soluble in vs not?
- organic compounds
- soluble in organic solvents
- not soluble in water
what is another term for lipids
- fat
describe the relation between fat & energy
- fat is the body’s chief storage place for excess food energy
- fat provides us with a large amount of energy to perform much of the body’s work
how do fat cells accomodate to store energy?
- they can expand indefinitely to store excess energy
describe the roles of fat during times of famine/starvation (2)
- brain & nerve cells develop the ability to gain half their energy from ketones
- during times of famine they enable us to survive thru the storage of excess food energy
list 3 other functions of lipids
- secrete hormones to regulate appeitie
- serve as basis for natural oils in skin & hair
- phospholipids & sterols in cell membrane
what happens when the body starts to run out of fuel from food
the body turns to body stores as a source of energy:
- fatty acids are used for energy by many organs
what is a “typical fuel mix” for use of energy by organs
- 50/50 carb/lipid for liver & muscle
what must be available any time fat is broken down for energy
- carbs
list 6 functions of fats in the body
- energy stores
- muscle fuel
- padding
- insulation
- cell membranes
- raw material
what is meant by the function of fat as padding?
- fat pads inside the body cavity protect the internal organs from shock
what is meant by the function of fat of insulation
- fats insulate against extreme temps by forming a fat layer under the skin
describe the relation between fats & cell membranes
- fats form the major material of cell membranes
describe the relation between fats & raw materials; give 3 examples
fats are converted to other compounds as needed, such as:
- hormones
- bile
- vitamin D
what are the 3 major classes of lipids
- triglycerides
- phospholipids
- sterols
what are triglycerides made of
- 3 fatty acids
- glycerol backbone
what are triglycerides
- major form of lipid found in the body & in foods
how are fatty acids (FA) classified?
- chain length (short, medium, long)
2. saturation (saturated, monosaturayed, polyunsaturated)
what does chain length of fatty acids mean
- refers to the number of carbons
what does saturation of fatty acids mean
- number of hydrogen bonded to the carbon
what are saturated FA
- every available carbon is bonded to full capacity by hydrogen atoma
- only single bonds between carbons
what are unsaturated FA? what do they result in?
- hydrogen atoms missing from chains
- results in double bonded carbon atoms = point of unsaturated
what does 1 vs 2 or more points of unsaturation mean
- 1 = monounsaturated
- 2 = polyunsaturated
fats with short chain or unsaturated FA are… (3); provide an example
- soft at room temp
- melt easily
- liquid at room temp (ex. oils)
saturated fatty acids are… (2); provide an example
- hardest at room temp
- do not melt easily
ex. lard
what is hydrogenation
- the combination of a hydrogen
what is the purpose of hydrogenating FA (2)
- makes them more firm at room temp –> increases solidity of fats
- makes fat less likely to go rancid (bad), stabilizes them
how are trans-fatty acids created? what does this result in?
- type of unsat fat that has been altered thru hydrogenation: occur as a result of changing configuration of hydrogen on the carbon chain
- makes them behave more like sat fats
- also greatly increased blood cholesterol levels
what do trans-fatty acids increase the risk of
- heart disease
what are solid fats
- fats that contain an abundance of trans & sat fats
what is an example of solid fats? where are they commonly found?
ex. shortening
- commonly found in grain-based desserts, pizza, etc.
describe the structure of phospholipids
- glycerol backbone
- 2 FA
- one phosphate group
what is an example of a phospholipid
- lecithin –> found in egg yolk
what are 3 functions of phospholipids
- play a major role in cell membrane
- generate signals in response to insulin
- used as emulsifiers
what are emulsifiers? what is an example
- chemical additives that encourage the suspension of one liquid in another
ex. the mixture of oil & water in margarine
how can phospholipids be used as emsulifiers
- one side is hydrophobic (fatty acids)
- one is hydrophillic (phosphate group)
what are sterols
- large molecules consisting of interconnecting rings of carbon atoms
- with side chains of carbon, hydrogen, and oxygen
what is an example of sterols
- cholesterol
what are plant sterols
- phytochemicals that interfere w cholesterol absorption in the intestinal tract
= lower blood cholesterol levels
where are significant levels of cholesterol found?
- only in animal products
ex. cheese, meat, eggs
what manufactures cholesterol? what happens to that cholestrol?
- the liver
- either goes to bile or enters cells
what is required to transport cholesterol
- lipoproteins
what does high cholestrol increase the risk of
- atherosclerosis
list the 4 structures involved in fat digestion & absorption
- mouth & salivary glands
- stomach
- small intestine & pancreas
- large intestine
describe the role of the mouth & salivary glands in fat digestion/absorption
- some hard fats begin to melt as they reach body temo
- the sublingual salivary gland in the base of the tongue secretes lingual lipase
- lingual lipase slightly hydrolysis’ most fats but is more effective for milk fats
describe the role of the stomach in fat digestion/absorption (2)
- the stomach’s churning action mixes fat with water & acid
- gastric lipase accesses & hydrolyzes (a small amt) of fat
describe the role of the small intestine & pancreas in fat digestion/absorption
- cholecystokinin (CKK) signals the gallbladder to release bile (via the common bile duct) = fat –> emulsified fat (triglycerides)
- pancreatic lipase flows in from the pancreas (via the pancreatic duct) = emulsified fat –> monoglycerrides, FA
describe the role of the large intestine in fat digestion/absorption
- some fat & cholestrol, trapped in fiber, is excreted thru feces
list 2 lipoproteins that are important in regards to heart health
- low density lipoprotein (LDL)
2. high density lipoprotein (HDL)
describe the relation between high LDL levels & heart disease
- high LDL = increased risk
describe the relation between high HDL and heart disease
- high HDL = low risk
list 3 ways to increase HDL levels
- maintain healthy body weight
- engage in physical activity
- quit smoking
list 3 ways to lower LDL
- maintain healthy body weight
- increase intake of soluble fiber
- reduce intake of sat and trans fat
describe the relation between blood cholestrol levels and heart disease risk
- important indicator
describe the impact of food cholesterol on blood cholesterol levels
- has little to no effect
describe the effect of high intakes of saturated & trans fat on LDL; what changes can be made to prevent this?
- high intakes of sat & trans fat = increased LDL
- replace sat & trans fat with mono & polyunsaturated FA will lower heart disease risk
what is one family of polyunsaturated FA
- omega-3 FA
where are omega-3 FA /polyunsat FA found?
- found abundantly in oils of fatty fish
- human milk
where is it preferred to get your omega-3 intake from
- preferred to get it from foods than supplements
what are potent protectors against heart disease?
- polyunsaturated FA (PUFA) of the omega-3 families
what are 2 examples of omega-3 FA
- EPA (eicosapentaenoic acid)
- DHA (docosahexaenoic acid)
what 2 things do omega-3 FA exert their beneficial effects on
- heart
- blood vessel
list 5 ways EPA and DHA protect heart health
- lower blood triglycerides
- lower bp
- prevent blood clots
- protect against irreg heartbeats
- defend against inflammation
list 5 examples of fish that are good sources of omega-3
- salmon
- char
- mackerel
- herring
- cod
list 4 lifestyle interventions that can lower the risk of cardiovascular disease
- increase physical activity/engage in regular physical activity
- lose weight
- avoid exposure to tobacco
- quit smoking
describe how smoking increases the risk of cardiovascular disease (6)
- promotes atherosclerosis
- decreases O2 reaching heart tissue
- raises HR
- inhibits vasodilation
- promotes blood clotting
- reduces exercise tolerance
describe how regular physical activity helps reduce the risk of cardiovascular disease (4)
- lowers LDL
- reduces bp
- increases insulin sensitivity
- promotes weight loss
list 10 dietary interventions to lower the risk of cardiovascular disease
- reduce sat & trans fats
- consume unsat fats
- increase soluble fibre intake
- increase intake of EPA and DHA
- limit alcohol intake
- reduce dietary sodium
- emphasize fruits, veggies
- whole grains
- fat-free or low-fat
- limit intake of sweets
how does increasing soluble fiber intake help reduce the risk of CVS disease
- lowers LDL by inhibiting cholesterol & bile absorption in the small intestine
what is hypertriglyceridemia
- elevated blood triglycerides
list 5 dietary or lifestyle interventions to manage hypertriglyceridemia
- engage in regular physical activity
- restrict alcohol intake
- limit intake of refined carbs
- limit intake of simple sugars
describe treatment of hypertriglyceridema in severe cases
- lifestyle changes paired w drug therapy & very low fat diet
who is hypertriglyceridemia common in (3)
- DM
- obesity
- metabolic syndrome
what is metabolic syndrome
- group of conditions that occur together to increase a person’s risk of other health problems
what are examples of conditions that are included in metabolic syndrome (5)
- insulin resistance
- increased BG levels
- abdominal obesity
- abnormal blood cholestrol
- high BP
what health problems does metabolic syndrome increase a person’s risk for (3)
- heart disease
- stroke
- type 2 DM
what can cause metabolic syndrome (3)
- genetics
- enviro
- abdominal obesity
what are 2 common treatments for metabolic syndrome
- weight loss
- increased physical activity
describe how abdominal obesity can cause metabolic syndrome
- visceral fat triggers a number of metabolic changes which promote insulin resistance
- release more fat into the blood increasing blood lipid levels & the kidney produces more VLDLs
obesity promotes insulin resistance. describe the effect of hyperinsulinemia and how that effects metabolic syndrome
- promotes sodium absorption in the kidneys
- high FA levels prompt vasoconstriction
- adipocytes produce angiotensinogen
= elevated BP
how does metabolic syndrome contribute to heart disease?
through:
- obesity
- high LDLs
- HTN
- atherosclerosis
- reduction in nitric oxide leading to reduced vasodilation
- release of pro-inflammatory cytokines which increase oxidative stress
what is the treatment for metabolic syndrome
- correct abnormalities that increase CVD and diabetes risk
list some examples of treatment for metabolic syndrome
- weight loss & physical activity to improve insulin resistance, BP, and serum lipid levels
- dietary & lifestyle modifications
- treat hypertriglyceridemia
- treat hyperglycemia
- treat HTN
- decrease sat & trans fat to treat the high LDL
- meds
how can we control HTN
- reduce sodium intake
how can we control hyperglycemia
- reduce carb intake
how can we control hypertriglyceridemia
- reduce added sugar, refined grain, increase whole grains, and foods high in fiber
what is the diagnostic criteria for metabolic syndrome (5)
- high BP (> 130/85, or receiving meds)
- high BG (>5.6, or receiving meds)
- high TG (>1.7, or receiving meds)
- low HDL (<1 in men, 1.3 in women)
- large waist circumference (>102 in men, 88cm in women)
what are the DRI recommendations for dietary fats? what is it specifically for sat and trans fat?
- 20-35% energy from dietary fat
- <10% from sat fats
- keep trans fat low as possible
what are the benefits of lowering sat and trans
- helps reduce blood cholestrol –> which reduces heart disease
what is a benefit (?) of unsat fat
- reduces blood clotting
what is the DRI recommendations for polyunsat fats
- 5-10% from linoleic acid (omega 6)
- 0.6-1.2% energy from linolenic acid (omega 3)
what is the DRI recommendation for cholestrol?
- minimize intake within context of healthy diet
what are 3 things you can limit to lower dietary cholestrol intake
- eggs
- shellfish
- liver
what types of oils are recommended
- raw oil in nuts, avacados, and seafood
list 4 vitamins that are important sources of fat?
- A, E, D, K
list examples of solid fat food sources
- steak
- candy
- cheese
- coconut
- burger
- most dessets
what are pros and cons of milk & yogurt products?
- rich in calcium & protein
- but also contain solid fats
describe fat in meats; what does loin mean’ what about chicken?
- make up most of our solid fat source & major source of sat fat
- labelled loin = fats trimmed off & are easily trimmable
- chicken is very lean and has lower fat content (besides skin)
describe fat in veggies or fruit; what are the exceptions? what type of fat?
- contains little to no
- avacado & olives are the exception
- almost all fat in unsat
a diet rich in _____ (4) offers abundant vitamin C, folate, vit A, vit E, and dietary fiber ?? what is another benefit of this diet? (2)
- veggies
- fruit
- whole grains
- legumes
- proctects against disease by reducing sat fat, total fat, and increasing nutrients
- provide valuable phytochemical that help defend against heart disease
what are fat replacers
- ingredients that replace some or all of the functions of fat & may or may not provide calories
what are some examples of fat replacers
- sugar
- fibre
- proteins
- olestra
what is olestra
- fat replacer with similar structure to fat
what is the benefit of olestra
- human enzymes do not recognize Olestra & do not split the fatty acids from the sucrose ring
= will pass thru the digestive tract and exit the body intact
how effective is low fat diets?
- findings indicate that it is not total fat intake that is to blame for higher rates of heart disease but rather the type of fat consumes
list 1 type of fat that supports good health; what type(s) is the big problem
- omega 3 = good
- sat, trans, problem
what type of diet is high in “good fats”
mediterranean
what type of foods are emphasized in mediterranean diets
fresh & whole foods:
- crusty breads
- whole grains
- potatoes & pasts
- veggies
- legumes
- feta & mozza
- yogurt
- nuts
- fruit
- some: fish, seafood, poultry, and eggs
- little meat
what are benefits of olive oil
protects against heart disease:
- lower blood clotting factors
- BP
- total and LDL cholestrol
what causes the effects of olive oil
- phytochemicals
what are the benefits of nuts
- contain few sat fats
- abdundance of mono & polysat fats
- provide fibre, veggies proteins, essential FA
- have phytochemical that act as antioxidants
what is the benefit of fish
- contain high omega 3
= promotes cardio health
what foods are highest in sat fats
- fatty meats
- whole milk products
- tropical oils (coconut)
what foods are highest in trans fat
- solid shortening
- margarine made from veggie oils
