Lecture 12 - How Good is this Groups Nutrient Intake

Question 1

why is information on group intake important

Answer 1

1. monitor population intakes
2. identify problem nutrients for a population
3. plan programmes to address problem nutrients
4. need to know appropriate methods to decide whether to believe (and use) papers you read

Question 2

what is the use of EAR in groups

Answer 2

use to estimate the prevalence of inadequate intakes within a group

Question 3

use of RDI in groups

Answer 3

DO NOT USE

Question 4

use of AI in groups

Answer 4

mean usual intake > this level implies low prevalence of inadequate intakes

Question 5

use of UL in groups

Answer 5

use to estimate %age of population at potential risk of adverse effects

Question 6

what are the steps to assessing nutritional adequacy in groups

Answer 6

step 1 : collect multiple days dietary data

step 2 : adjust intake distribution

step 3 : use EAR to determine adequacy

Question 7

what is the first step to assessing nutritional adequacy in groups

Answer 7

collect multiple days dietary data

• diet record : collect 2+ independent days (or 3+ consecutive days)
• 24hr recall : collect 2nd independent day in >50%

Question 8

what is step 2 to assessing nutritional adequacy in groups

Answer 8

adjust distribution of observed intakes to remove day to day variability in intakes

Question 9

what are the two methods for step three of assessing nutritional adequacy in groups

Answer 9

use EAR to determine adequacy

• cut point methods
• probability approach

Question 10

what is the EAR cut point method

Answer 10

prevalence of inadequacy ~ proportion of group with intakes < EAR

Question 11

what does the EAR cut point method assume

Answer 11

• no correlation between intakes and requirements
• distribution of requirements is symmetrical
• variance of intakes > variance in requirements
• prevalence of inadequate intakes is neither very high nor very low (ideally 10-90%)

Question 12

in the EAR cut point method, if your values are higher than the EAR but your intake is lower than your requirement then

Answer 12

you are part of the group that are missed by the EAR cut point method

Question 13

in the EAR cut point method, if your values are above what you need but below the EAR you are considered a

Answer 13

false positive

Question 14

in the EAR cut point method the number of false positives and negatives should

Answer 14

be the same and cancel each other out

Question 15

what is the probability approach

Answer 15

the prevalence of inadequacy = weighted average of risks at each intake level

Question 16

the probability approach assumes

Answer 16

no correlation between intakes and requirements

Question 17

the probability approach must be used if

Answer 17

• Fe in premenopausal women
• if prevalence inadequate intakes very high or low in population

Question 18

what are the steps to the probability approach

Answer 18

1. construct a risk curve (gives probability for each intake level that intake is inadequate)
2. determine % of intakes in each risk category
3. determine prevalence of inadequacy

Question 19

the AI can not be used to

Answer 19

determine the prevalence of inadequate intake in a group

Question 20

when using the AI for a group, mean intake of group is > AI then

Answer 20

prevalence inadequate intakes probably low

Question 21

when using the AI for a group, mean intake of group is < AI then

Answer 21

can not determine adequacy

Question 22

when using the Ai for a group it assumes

Answer 22

variance of intake similar to that of population AI based on

AI based on mean intake of healthy population

Question 23

when using the UL for groups , it uses

Answer 23

similar approach to the EAR cut point method

Question 24

when using the UL for groups it uses appropriate

Answer 24

intake distribution

e.g
- some nutrients need intakes from all sources (like Vitamin C)

• some nutrients need intakes from supplements only (like Vitamin E)

Question 25

what are the limitations for determining group nutrient adequacy

Answer 25

• cant use EAR cut point method or probability methods to identify specific people with inadequate intake
• full probability approach time consuming
• don’t have EAR for all nutrients

Question 26

group nutritional adequacy methods can only be used for

Answer 26

groups not individuals because there are some false positives and negatives with the cut off method and issues with the probability method

Question 27

things not to do when assessing nutrition groups

Answer 27

• compare group mean intakes to EAR or RDI
• use EAR cut point method to assess Fe intake in premenopausal women
• use EAR cut point method for small groups (<30)
• use the proportion of the groups < RDI
• forget to adjust for day-to-day variation in intakes