Dietary Reference Intakes Applications in Dietary Planning (2003) / Chapter Skim
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4. A Theoretical Approach Using Nutrient Density to Plan Diets for Groups
4. A Theoretical Approach Using Nutrient Density to Plan Diets for Groups
Pages 89-106
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From page 89... ...
This approach takes into account the differences both in energy and nutrient needs of the distinct subgroups to derive target nutrient intake distributions expressed as nutrient densities. The medians of the target nutrient density intake distributions for the various subgroups are then compared to set planning goals for the whole group.
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From page 90... ...
The problem with this approach, however, is that even if the planning appears to meet the group neeci for the nutrient, there is no guarantee that nutrient intakes will be clistributeci among inclivicluals in the group in a manner to satisfy nutrient requirements. For example, in planning for iron intakes for a group of men and women, simply computing the average iron requirement and planning accordingly does not ensure that incliviclual group members will have their iron requirement satisfied.
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From page 91... ...
; it is assumed that the other subgroups will obtain acloquate nutrient intakes if they fulfill their energy requirements. This approach, while simple and straightforward to implement, does not consider the variability in energy intakes within a subgroup and may therefore result in a prevalence of inacloquacy that differs from the planning goal.
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From page 92... ...
By planning for a nutrient density that is acloquate for the subgroup with the highest neecis, it is possible that a substantial proportion of some of the other subgroups will consume cliets that exceed the UL. Each of the methods proposed above requires an estimate of the distribution of usual nutrient intakes in the various subgroups of interest.
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From page 93... ...
The following discussion assumes that one can approximate the distribution of usual energy intakes in the subgroup of interest by using self-reporteci energy intake ciata. It is important to recognize, however, that insofar as systematic reporting errors distort the clistribution of usual energy intakes, these errors may seriously bias estimates of the distribution of both nutrient requirements and nutrient intakes expressed as densities.
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From page 94... ...
has been cletermineci, the target meclian nutrient intake is the meclian of the distribution obtained by repositioning (if necessary) the usual nutrient intake distribution in the subgroup of interest so that an acceptably low proportion of inclivicluals in the subgroup has intakes below the EAR.
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From page 95... ...
cat , Assessing the adequacy of the group's nutrient intakes is particularly critical when this approach to dietary planning is used. By using only the mean energy intake or requirement of each subgroup, it fails to consider the variability of energy intakes among members of a subgroup.
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From page 96... ...
2. Combine the target distribution of usual nutrient intakes with the usual energy intake (or expenditure distribution in each subgroup to obtain the target distribution of usual nutrient intakes expressed as densities.
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From page 97... ...
While the method presented in Chapter 3 essentially consisted of repositioning the usual nutrient intake distribution, an aciclitional step is neecleci when planning for a heterogeneous group. The target usual nutrient intake distribution must be combined with the distribution of usual energy intakes in each subgroup to obtain the target nutrient density intake distribution.
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From page 98... ...
The calculation above can be taken one step further if one considers a group in which inclivicluals vary in their usual nutrient intake. In the unlikely case in which everyone in the group has the exact same usual energy intakes, say 2,000 kcal, then given the distribution of usual nutrient intakes in the group, it is a simple matter to calculate the usual intake distribution of the nutrient expressed as a density: simply clivicle each usual nutrient intake in the group by 2,000 and multiply by 1,000.
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From page 99... ...
To derive the target usual nutrient density distribution, each value in the target nutrient intake distribution is paired with each value from the energy intake distribution, as shown in Table 4-1. As shown in the fourth column of the table, the target nutrient density intake distribution ranges from 3.33 units/1,000 kcal to 7.0 units/1,000 , , ——— ~
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From page 100... ...
It can be seen that none of the men would have intakes below the EAR of 10 units, so the planned-for very low prevalence of inadequacy would be attained. In practice, it is not really necessary to proceed with the average over all energy consumption levels as above, nor is it necessary to
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From page 101... ...
density for each of the q usual nutrient intakes drawn from the distribution in the subgroup would then be calculateci as inclicateci in either of the two expressions presented above. In the example in Chapter 5, q= 400, so that about 10 percent of the usual vitamin C intakes for women were drawn from the target usual intake distribution to compute the incliviclual weighted averages using equation (2~.
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From page 102... ...
~ 1 The target nutrient density intake distribution is obtained from an adequate target nutrient intake distribution, and therefore the resulting target distribution of nutrient density intakes meets the criterion for adequacy that was selected. It is also important to monitor the proportion of indiv?
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From page 103... ...
Correlation Between Nutrient Intakes and Energy Intakes A premise of the nutrient density distribution approach to planning intakes of heterogeneous groups is that the correlation between usual nutrient intakes and usual energy intakes is moclerate to low. This assumption permits computing the simple Monte Carlo average that results in a target distribution of nutrient density intakes in each subgroup.
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From page 104... ...
Note that while the discussion below relates primarily to the nutrient density distribution approach, the issues raised are equally relevant to the simple approach that relies on the estimated meclian energy intake. The estimated distribution of usual energy intakes is required to derive a distribution of nutrient requirements expressed as clensities when planning intakes of a single food or of a cliet composed of a variety of foocis with similar nutrient density.
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From page 105... ...
If some of the energy intakes are systematically unclerreporteci, but the target nutrient intake clistribution is less affected by underreporting, then some overestimation of nutrient requirements in relation to energy would occur. If energy and nutrient intakes have both been unclerreporteci to the same extent, then the target density intake distribution may be less biased.
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From page 106... ...
All of these parameters are subject to measurement error, particularly if selfreporteci ciata are used. Furthermore, use of the energy expencliture equations floes not eliminate the neeci to use self-reporteci nutrient intake ciata to obtain an estimate of the target nutrient intake distribution.
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