1 - DRIs Flashcards
expand RDA by current and past definitions. when were RDAs first published?
current: Recommended Dietary Allowances
past: Recommended Daily Allowances
published: 1941
expand RNI. when first published?
Recommended Nutrient Intakes
published: 1938
why did the D change from daily to dietary in RDA?
daily is a misnomer bc in reality, your body can use stores of nutrients. the specified amount is averaged out over days/months.
what largely determines a vitamin’s turnover rate in the body?
water/fat solubility
when were RNIs, safe levels of intake, and RDAs last reviewed?
RNI: 1990
Safe Level of Intake: 1985
RDA: 1995
why are upper reference levels made?
came about as a result of toxicity associated with recent fortification/supplementation
How many nutrient-based references are there for DRIs? what are they?
four: EAR, RDA, AI, UL
what is EAR?
Estimated Average requirement (from which RDA is determined)
what is RDA?
recommended Dietary allowance, which replaces the former RDA and RNI
what is AI?
Adequate Intake (alternative reference when EAR and consequently RDA are not available)
what is UL?
Tolerable Upper Intake Level
True or false: a nutrient without an EAR has an RDA
false
what percentage of people will receive sufficient nutrition by consuming an EAR?
50%
what percentage of people will receive sufficient nutrition by consuming an RDA?
97.5%
how is an RDA determined?
2 standard deviations above an EAR
true or false: not all nutrients have an RDA
true
RDAs are determined on experimentation on a (compromised/healthy) population
healthy - RDAs are usually deficient for sick people
RDAs are based on estimation of a minimal requirement to achieve some ______ _____
measurable outcome
what are some limitations of RDAs?
since it’s based on young/healthy ppl, it poses risk to elderly which have different needs
extrapolation downward for childhood is also a limitation, potentially becoming deficient due to their growth needs
what is a balance study?
finds point of input that leads equal output
what kind of studies to RDAs consider in addition to healthy people?
- deficiency states
- balance studies
- animal research
what must an RDA account for?
- individual variability in a population
- bioavailability
- sex and age differences
- physiological state
what’s coefficient of variation?
CV = sd/mean
what is a limitation of Canada’s RDAs regarding bioavailability?
they are based on the fact that animal proteins are a normal part of the diet. it does not account well for vegetarian diets. on this bases, the values of absorption need to be much higher for vegetarians or vegans, esp because of phytates, tannins, & oxalates which are more prevalent here.
growth tends to (increase/decrease) nutrient requirements
increase
what are 2 examples of different physiological states that affect efficacy of RDAs?
pregnancy, lactation
when are EARs suitable to use?
intakes for GROUPS
EARs are based on the intake _____ of the group and not the _____ intake
based on intake distribution
not average intake
How do you set an RDA when the SD of EAR is available?
RDA = EAR + 2SD
how do yous et an RDA when the SD of EAR is not available?
assume CV = 10% calculate SD using the CV formula using EAR as mean, so: CV = SD/EAR. rearrange to: SD = EAR x CV then: RDA = EAR + 2SD
when are RDAs suitable to use?
as reference points for INDIVIDUALS
what do RDAs allow an estimate of?
probably risk of deficiency for an individual when diet is assessed over time
at what percentage of the RDA is an individual considered to be at high risk for deficiency and in need for an intervention?
66%
what kind of diets are intended for RDAs?
one with a variety of foods
true or false: prevention of chronic disease is being considered as part of the RDA development
true (like folate)
what are RDAs NOT designed to do?
- overcome nutrient deficiencies
- recover from illness
how do you estimate target mean intakes using EAR values?
EAR/(1-[2 x CVintake])
expand DRI
Dietary Reference Intakes
how are DRIs different from former RDAs and RNIs?
1) reduction in risk of chronic degenerative disease in included
2) concepts of probability/risk explicitly underpin the determination of the DRIs, and applications
3) upper levels of intake are established
4) food components that may not meet the traditional concept of a nutrient are considered
name some examples of nontraditional food component that aren’t really nutrients but are still important
- polyphenols
- carotenoids w/o vit A activity (zeaxanthin and leutin)
when are AIs used?
when an EAR cannot be calculated
true or false: intakes below the UL are unlikely to pose risks of adverse health effects in healthy people
true
what are DRIs?
refers to a set of reference values used to plan diets of healthy ppl. includes RDA, AI, and UL,
what are AIs based on?
- observed or experimentally determined approximations
- estimates of nutrient intake by groups (or groups) of healthy people that are assumed to be adequate
- used when RDA cannot be determined
how likely is a diet to be adequate if intake > AI?
almost certainly adequate
how likely is a diet to be inadequate if intake < AI?
no quantitative/qualitative estimate can be made of the probability of nutrient adequacy bc the point where risk increases cannot be determined
true or false: consuming ULs is likely to pose risk of adverse health effects for almost all individuals in the general population
false
what influences the gap between the RDA and UL?
the individual nutrient and life stage. elderly folks have a wider gap (can tolerate greater levels beyond the RDA)
