NUTR 3330 NEW EXAM WITH QUESTIONS AND 100%
CORRECT DETAILED ANSWERS
What are phytosterols? - ANSWER - plant derived sterols
- structurally similar to cholesterol
- not synthesized by humans (must come from diet or supplements)
- over 40 phytosterols identified but most common
= beta-sitosterol
= campesterol
= stigmasterol
What are the subdivisions of phytosterols? - ANSWER 1. phytoSTEROLS
- indicates double bond at position 5
- most common
- structure VERY SIMILAR TO cholesterol
2. phytoSTANOLS
- indicates 5alpha-reduction of double bond
- saturated derivative of phytosterols
- less common
- low in food, mainly product of intestinal bacterial degradation of phytosterols
- also produced by hydrogenating sterols
What are similarities and differences between phytosterols and cholesterol? - ANSWER
- cholesterol is from animal foods
- phytosterols are plant foods
- both are atherogenic (build up of plaque in arteries)
, = not concern with phytosterols because only 1-15% are absorbed
= blood levels of phytosterols are 200x lower than cholesterol
What are the units of phytosterols/phytostanols? - ANSWER mg/day not g/day
- very low intake value!!
What are the 3 areas of health focus for phytosterols/phytostanols? - ANSWER 1.
cardiovascular disease (most attention)
2. cancer (mainly cell culture studies)
3. immunity (limited evidence)
What is concluded about 2 g of plant sterols or stanols per day? - ANSWER - decreased
plasma LDL cholesterol by 9-14% (very big %)
- no effects on HDL cholesterol or TG
- estimated to reduce heart disease risk by 25% (very big %)
What is the amount of phytosterols recommended to lower LDL cholesterol? - ANSWER
2-3 grams/day
How does phytosterols/phytostanols lower cholesterol? - ANSWER 1. competes with
cholesterol for limited space on mixed micelles in the intestine
2. more hydrophobic than cholesterol therefore higher affinity for micelles
3. displace cholesterol from micelles into feces (but phytosterols/phytostanols not
absorbed so into feces as well)
4. decreases cholesterol absorption by 30-50%
- dietary by 20%
- endogenous cholesterol from body by 80%
What are factors to consider for phytosterols/phytostanols and cholesterol lowering? -
, ANSWER - phytosterols vs phytostanols (does not matter which form)
- dose (threshold)
- format ( does not need to be in food with cholesterol because it competes with
endogenous cholesterol as well)
- background diet
- baseline cholesterol values
Can use of phytosterols/phytostanols replace lipid-lowering drug? - ANSWER - avoid
side effects
- reduced cost as cost about 3x less
- effect magnitude = phytosterols/phytostanols less effective
phytosterols/phytostanols vs drug study - ANSWER - phytosterols/phytostanols reduces
cholesterol absorption
- followed by compensatory increase in cholesterol synthesis
- concurrent use of HMG-CoA reductase inhibitor may yield synergistic effect
- there is an additive effect of both phytosterols/phytostanols and cholesterol lower
drugs by 39%
How does phytosterols/phytostanols increase their incorporation into foods? - ANSWER
- ability to incorporate phytosterols/phytostanols on food is limited due to low solubility
in fats
- by esterfying them to fatty acid it increase their incorporation into fat soluble foods by
10x
What food products have phytosterols/phytostanols? - ANSWER - margarine
- other dairy products
- minute maid heart wise orange juice
What cancer does phytosterols/phytostanols help against? - ANSWER 1. prostate
CORRECT DETAILED ANSWERS
What are phytosterols? - ANSWER - plant derived sterols
- structurally similar to cholesterol
- not synthesized by humans (must come from diet or supplements)
- over 40 phytosterols identified but most common
= beta-sitosterol
= campesterol
= stigmasterol
What are the subdivisions of phytosterols? - ANSWER 1. phytoSTEROLS
- indicates double bond at position 5
- most common
- structure VERY SIMILAR TO cholesterol
2. phytoSTANOLS
- indicates 5alpha-reduction of double bond
- saturated derivative of phytosterols
- less common
- low in food, mainly product of intestinal bacterial degradation of phytosterols
- also produced by hydrogenating sterols
What are similarities and differences between phytosterols and cholesterol? - ANSWER
- cholesterol is from animal foods
- phytosterols are plant foods
- both are atherogenic (build up of plaque in arteries)
, = not concern with phytosterols because only 1-15% are absorbed
= blood levels of phytosterols are 200x lower than cholesterol
What are the units of phytosterols/phytostanols? - ANSWER mg/day not g/day
- very low intake value!!
What are the 3 areas of health focus for phytosterols/phytostanols? - ANSWER 1.
cardiovascular disease (most attention)
2. cancer (mainly cell culture studies)
3. immunity (limited evidence)
What is concluded about 2 g of plant sterols or stanols per day? - ANSWER - decreased
plasma LDL cholesterol by 9-14% (very big %)
- no effects on HDL cholesterol or TG
- estimated to reduce heart disease risk by 25% (very big %)
What is the amount of phytosterols recommended to lower LDL cholesterol? - ANSWER
2-3 grams/day
How does phytosterols/phytostanols lower cholesterol? - ANSWER 1. competes with
cholesterol for limited space on mixed micelles in the intestine
2. more hydrophobic than cholesterol therefore higher affinity for micelles
3. displace cholesterol from micelles into feces (but phytosterols/phytostanols not
absorbed so into feces as well)
4. decreases cholesterol absorption by 30-50%
- dietary by 20%
- endogenous cholesterol from body by 80%
What are factors to consider for phytosterols/phytostanols and cholesterol lowering? -
, ANSWER - phytosterols vs phytostanols (does not matter which form)
- dose (threshold)
- format ( does not need to be in food with cholesterol because it competes with
endogenous cholesterol as well)
- background diet
- baseline cholesterol values
Can use of phytosterols/phytostanols replace lipid-lowering drug? - ANSWER - avoid
side effects
- reduced cost as cost about 3x less
- effect magnitude = phytosterols/phytostanols less effective
phytosterols/phytostanols vs drug study - ANSWER - phytosterols/phytostanols reduces
cholesterol absorption
- followed by compensatory increase in cholesterol synthesis
- concurrent use of HMG-CoA reductase inhibitor may yield synergistic effect
- there is an additive effect of both phytosterols/phytostanols and cholesterol lower
drugs by 39%
How does phytosterols/phytostanols increase their incorporation into foods? - ANSWER
- ability to incorporate phytosterols/phytostanols on food is limited due to low solubility
in fats
- by esterfying them to fatty acid it increase their incorporation into fat soluble foods by
10x
What food products have phytosterols/phytostanols? - ANSWER - margarine
- other dairy products
- minute maid heart wise orange juice
What cancer does phytosterols/phytostanols help against? - ANSWER 1. prostate
