Module 1 - Introduction, Dietary Reference Intakes Flashcards
What are DRIs?
A set of nutrient-based reference values
What do DRIs serve as a basis for?
almost all federal and state food & nutrition programs and policies (ex: SNAP & WIC)
DRIs apply to who?
only to healthy people
The DRI was published by who?
the national academy of sciences
What year was the DRI first published in?
1941
Why may DRIs differ for individuals?
because they are at different life stages
What are the 5 stages of the development of nutritional deficiency?
- dietary inadequacy (assessed by diet)
- decreased reserves (assessed biochemically)
- decreased levels in body fluids (assessed biochemically)
- decreased function/change in enzyme activity (assessed by anthropometric/biochemical)
- clinical symptoms (assessed clinically)
What are studies used to determine DRIs?
- animal models
- human feeding studies
- observational studies
- randomized controlled trials
When are animal models used?
used when human data is not available
Human feeding studies involve what?
controlled feeding studies in metabolic wards
Observational studies look at what?
free living subjects
Which study is used to determine if DRI is considered gold standard?
randomized controlled trials
Why may adjustments be made to the DRI?
because the body’s ability to absorb and use nutrients can vary depending on the food source or whether supplements are used
What does EAR stand for?
estimated average requirements
What is EAR?
the average daily nutrient intake level estimated to meet the requirement of half the healthy individuals in a particular life stage and gender group
The EAR plans intakes for who/what?
groups
What is the EAR the basis for?
RDA values
Why are studies to determine EAR limited?
limited due to few human studies
The EAR is an indicator used for what?
indicator used for nutrition intake adequacy which is important in determining requirement
What is the vit D EAR for females and males aged 19-30?
400 IU
True or False: The EAR should be used as the goal for mean intake?
False (EAR is estimated to meet the requirement of half the healthy individual but can result in half the inadequacy)
What does RDA stand for?
recommended dietary allowance
What are RDAs?
the average daily nutrient intake level sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in a particular life stage and gender group
Usual intake at RDA would have
low inadequacy probability
What is the vitamin D RDA for females and males aged 19-30?
600 IU
What is the ideal process for establishing an RDA?
- select healthy, representative sample of population
- determine EAR
- assess range of individual variability
- calculate allowances to cover needs of nearly all healthy individuals
What is the RDA equation?
RDAs = EAR + 2SD
What does AI stand for?
adequate intake
What is AI?
the recommended average daily intake level based on observations or experiments with healthy people
When is AI used?
when an RDA cannot be determined (insufficient data available, cannot do randomized trial)
What is the AI for vitamin D in infants aged 0 to 6 months and 6 to 12 months?
400 IU
What does AI represent?
the group mean intake of an apparently healthy group of people
Similar groups with mean intake at or above ai can be assumed to have what?
low prevalence of inadequate intakes
What happens when mean intakes of groups are below ai?
it is NOT possible to make any assumption about inadequacy
Issuance of an AI is an indication of what?
that more research is needed
When can AI be replaced by EAR?
when more evidence/data is available
There is less certainty about ________ than about RDAs
AI
AIs must be used with
reservation and caution
What is Tolerable upper Intake Level (UL)?
the maximum daily nutrient intake that is unlikely to cause health risks for most people
As intake increases above the UL, the potential risk of adverse effects may _______
increase
What is the UL of vitamin D in females and males aged 19 to 30?
4,000 IU
What are the challenges to setting UL?
- absence of dose-response data
- few studies in humans or animals
- few surveillance studies to establish no-observed adverse effect level
- available databases concentrate on supplement intake, not total
- significant differences in bioavailability
The ULs grew out of what?
increased fortification and supplements
What does it mean if someone is below the EAR or RDA on the DRI curve?
risk of inadequacy increases
What does it mean if we go above the UL on the DRI curve?
risk of adverse effect increases
RDA accounts for who?
majority of healthy individuals
EAR accounts for who?
50% of people
The requirements for iron are
the same up to 14, then biological sex changes it (menstruation)
RDAs and AIs are
levels of intake recommended for individual
Nutrient needs may be based on
body size
For purposes of the EAR or UL, what was used to establish age/gender values?
reference weights and heights
Within the 4-8 year old range, who would have a smaller requirement? A 4 year old or an 8 year old?
4 year old (RDA or AI cover both)
Is dietary assessment an exact science?
no
What is dietary assessment?
The best estimate of individual or group intake
What does dietary assessment calculate?
The probability of inadequacy for individuals and prevalence of adequacy within a group
Assessing an individual’s nutrient adequacy requires knowing what?
- individual’s requirement for that nutrient
- individual’s long-term usual intake of that nutrient
(neither are usually known –> assumptions are needed)
When assessing an individual’s diet we assume what?
that the individual’s requirement is the same as the EAR
Is an RDA appropriate for assessing groups?
no, it meets or exceeds requirements of 97%-98% of individuals. using RDA would overestimate the proportion of the group at risk of inadequacy
What judgement can you make if usual intake is equal to RDA?
intake is adequate
RDAs can be used in planning for what?
groups and individuals, but not in assessing adequacy or intake
What would happen if an RDA was used to assess groups?
it would overestimate the proportion of the group at risk of inadequacy
What judgement about nutrient adequacy can you make if usual intake is < EAR?
a. intake is inadequate
b. intake is adequate
c. intake is similar to RDA
a. intake is inadequate
What judgement about nutrient adequacy can you make if usual intake is equal to RDA?
a. intake is inadequate
b. intake is adequate
c. intake is similar to EAR
b. intake is adequate
In individuals what do EARs examine?
examine the possibility of inadequacy
In groups, what do EARs examine?
examine the prevalence of inadequate intakes within a group
What does it mean if an individuals usual intake is at or above the RDA?
they have low probability of inadequacy
What is RDA not used to assess?
not used to assess intakes of groups
What does it mean if an individuals usual intake is at/above the AI?
they have a low probability of inadequacy
What does it mean if a groups mean intake is at/above the AI?
low prevalence of inadequate intakes
What does it mean if an individuals usual intake is above the UL?
they may be at risk of adverse effects
What are ULs used to estimate?
used to estimate the % population at potential risk of adverse effects from excessive nutrient intake
What are the limitations of DRIs?
- EAR may be based on data from limited number of individuals
- Precise variation in requirements is approximated
- Normal distribution
What are DRIs used for?
- assess diets of individuals and populations
- basis for nutrition education
- food assistance program planning (ex: school meals, WIC)
- to assess impact of interventions
- food fortifications
- food products
Suzanna is a vegetarian and wants to know what iron intake she should be eating. What DRI level do you recommend?
a. EAR
b. RDA
c. AI
d. UL
b. RDA
You are conducting a research project where you are comparing US children (9-10 y/o) dietary vitamin D intake with recommended levels. Which DRI level should you use?
a. EAR
b. RDA
c. AI
d. UL
a. EAR
Which DRI level do infants use?
AI
Which DRI level do kids, aged 9-10, use?
EAR
