Dietary Reference Intakes Applications in Dietary Planning (2003) / Chapter Skim
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3. Using Dietary Reference Intakes in Planning Diets for Groups
3. Using Dietary Reference Intakes in Planning Diets for Groups
Pages 55-88
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From page 55... ...
This information is used to plan for a usual nutrient intake distribution in which intakes will meet the requirement of all but a specified proportion of the group. This framework importantly shifts the focus of planning away from past practices of using dietary recommendations or Recommended Dietary Allowances to decide what to serve, toward what is ultimately desired in terms of the distribution of usual intakes as measured by actual consumption.
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From page 56... ...
Because the goal of planning is to achieve a clesireci distribution of usual intake, it is clear that to judge the success of the planning activity, assessment must occur. In most situations, planning group cliets is an iterative, ongoing effort in which planners set planning goals for usual intake, assess whether the goals are achieved, and then mollify their planning procedures accordingly.
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From page 57... ...
Because this framework considers the distribution of usual nutrient intakes of the group as the basis for planning, it shifts the focus of planning away from using clietary recommendations in clecicling what to offer, to what is ultimately clesireci in terms of the distribution of usual nutrient intake. By focusing explicitly on the distribution of nutrient intakes of a group as the goal of group planning, the framework presented below is, in many respects, a new paradigm, and it should be tested before beingimplemented in large-scale group-feeding situations.
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From page 58... ...
OVERVIEW OF PLANNING FOR NUTRIENT INTAKES OF GROUPS Planning nutrient intakes for a group is difficult because inclivicluals in a group, even if offered the same meal, vary in the amount and selection of foocis that they eat. Planning for group fouling typically focuses on planning for institutional feeding, which includes such settings as residential schools, prisons, military garrisons, hospitals, and nursing homes.
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From page 59... ...
the variance in intakes is larger than the variance in requireConcept of a Target Usual Nutrient Intake Distribution Suppose a planner is interested in planning a group diet with a high probability of nutrient adequacy (e.g., such that the prevalence of inadequacy in the group is no more than 2 to 3 percent)
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From page 60... ...
If the planning goal was to attain a prevalence of inaclequacy of no more than 2 to 3 percent, the target usual nutrient intake distribution could be achieved by simply shifting the baseline usual intake distribution up, as shown in Panel B The appropriate shift (up or down)
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From page 61... ...
Shifting the baseline distribution up so that the prevalence of inadequate intakes reflects the planning goal (in this example, 2 to 3 percent) attains the target usual nutrient intake distribution (Panel B)
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From page 62... ...
The median of the current zinc distribution for these girls is 9.4 mg/day, so the meclian of the target usual nutrient intake distribution would be 9.4 + 0.8 = 10.2 mg/day. The median of a target usual nutrient intake distribution exceeds the RDA because the variance in usual intakes typically exceeds the variance of the requirement.
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From page 63... ...
These include: · estimating the existing or baseline distribution of usual nutrient intake; · selecting the target prevalence of inacloquacy; · estimating the target usual nutrient intake distribution; · assessing the feasibility of obtaining the target usual nutrient intake distribution; and · planning for groups when assumptions of the Estimated Average Requirement cut-point method are violated. Estimating the Existing or Baseline Distribution of Usual Nutrient Intake Estimating the target usual nutrient intake distribution requires information about the shape of the existing distribution of usual nutrient intakes.
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From page 64... ...
In these situations it may be possible to approximate the percentiles of usual intake for the target group from existing data on usual intakes for a group with similar characteristics. Distributions of usual nutrient intake derived from general population surveys are presented in appendixes to the DRI reports (IOM, 1997, 1998a, 2000b, 2001, 2002a)
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From page 65... ...
The intake clistribution will simplistically be assumed to be normal, with a standard deviation of usual intake of 18 units. Panel A, with a group prevalence of inadequacy of 2 to 3 percent, is similar to the target usual nutrient intake distribution portrayoci in Figure 3-1, while Panels B and C show the two scenarios clescribeci above.
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From page 66... ...
.. _ ~ 86 101 A RDA = Median of the Target E R Intake Distribution Requirement Distribution Intake Distribution — 50 65 86 Usual Intake FIGURE 3-2 Panel A: low group prevalence of inadequacy: 2.5 percent of the population has usual intake below the estimated average requirement.
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From page 67... ...
When the target usual nutrient intake clistribution is positioned to have a meclian equal to the RDA, the expected prevalence of inacloquate intake is fairly high, around 28 percent in this example. The reason for this apparent inconsistency is the variance in usual intake that is observed in most groups.
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From page 68... ...
of inacloquacy is the underlying goal, then meals, food plans, and food assistance benefits for groups must offer substantially more than the RDA for the resulting distribution of usual intake to achieve this goal. On the other hanci, planners might clecicle that a target usual nutrient intake distribution with a meclian intake equal to the RDA is the planning goal (Panel C)
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From page 69... ...
would be expected when the meclian intake was 86 units (86 = 50 + t1.96 x 181~. Estimating the Target Usua;t Nutrient Intake Distribution Assuming a Non-Norma;t Distribution of Usua;t Intake In most cases, however, the distribution of usual nutrient intakes is not normally clistributeci, so the Unusual intake cannot be used to iclentify the position of the target usual nutrient intake distributions The approach to estimating the target distribution for a non-normal usual intake distribution is similar in principle to the approach clescribeci above, although it floes not clepenci on the SD of intakes and a Z value.
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From page 70... ...
That shift is about 0.8 ma, so the target usual nutrient intake distribution would have a meclian of about 9.4 + 0.8 = 10.2 mg (where 9.4 is the observed meclian zinc intake for this group) , if it is assumed that the shape of the distribution floes not change with whatever intervention is required to increase intakes by 0.8 ma.
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From page 71... ...
Feasibility of Obtaining the Target Usual Nutrient Intake Distribution The principle underlying the framework for planning for group fouling is that information on the nutrient requirements and usual intakes can be used to develop a plan where intakes will meet the requirements of all but a targeted proportion of the group. In esti
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From page 72... ...
In group-feecling situations, such as nursing homes or other long-term care facilities where staff have a good knowledge of food consumption patterns and are able to tailor menu options to meet the preferences of most inclivicluals in the group, target usual nutrient intake distributions may be readily attainable. Planners may also be able to manipulate the variance in usual intakes to some extent through the design of menus.
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From page 73... ...
, the method overestimates the true prevalence. Thus, if planning for normal group feecling involves a nutrient where the requirement distribution is not symmetric, positioning the target usual nutrient intake distribution as a function of the EAR will not achieve the targeted risk of inacloquacy.
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From page 74... ...
Instead of using the EAR cut-point method to define that target usual intake distribution, however, the probability approach can be used. In this case, the first step is to estimate the distribution of usual intakes in the group.
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From page 75... ...
, the distribution of usual intakes may display less variance than the distribution of incliviclual requirements for a particular nutrient. When this is confirmed or strongly suspected, the probability approach is the preferred methoci to define the target usual nutrient intake distribution.
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From page 76... ...
Two approaches to meeting this objective could be consiclereci: estimate requirements for the reference person used to establish the Dietary Reference Intakes (DRIs) , or obtain an average of estimated requirements for group members.
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From page 77... ...
and then use the average of these values as the average group-planning goal. Table 3-3 shows an example of how this could be clone for a small group of six healthy men.
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From page 78... ...
For protein, the prevalence of usual intakes both below and above the acceptable range is essentially zero, so one might plan to maintain the current usual intake distribution with a meclian intake of 15.6 percent of energy. For carbohydrate, however, approximately 20 percent of women have usual intakes below 45 percent of energy, the lower end of the range.
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From page 79... ...
In contrast, for fat the prevalence of intakes below 20 percent of calories is essentially zero (< 1 percent) , but over 25 percent of women have usual intakes above the upper end of the range (> 35 percent)
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From page 80... ...
PLANNING MENUS TO ACHIEVE TARGET USUAL NUTRIENT INTAKE DISTRIBUTIONS After the planner has estimated a target usual nutrient intake distribution for each nutrient of interest, this information then neecis to be incorporated into a plan of how to feeci a group such that the target usual nutrient intake distribution is achieved.
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From page 81... ...
establishing an initial goal for the nutrient content of the menu that is based on the target usual nutrient intake distribution; 2. determining what foods to offer that will most likely result in a distribution of usual nutrient intake that approximates the target, and thus attains the desired probability of nutrient adequacy; and 3.
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From page 82... ...
In an attempt to offer practical guidance to planners, several still-tobe-testeci assertions may be of use: · Offering meals with an average nutrient content equal to the meclian of the target usual nutrient intake distribution is likely to result in lower than planneci-for acloquacy of intakes. This is because inclivicluals in a group tend to consume less than what is offered to them.
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From page 83... ...
In these cases the AI is similar conceptually to the meclian of a target usual nutrient intake distribution. In other cases the AI is the level of intake at which subjects in an experimental study met the criterion of acloquacy.
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From page 84... ...
. Thus, regardless of how the AI has been estimated, it is not possible to use the AI to plan a target distribution of usual intakes with a known prevalence of inadequacy.
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From page 85... ...
0-12 mo 1-18 y 19-50 y > 50 y Pregnancy and lactation (all ages) Group Mean Intake Total fiber n-6 Polyunsaturated fatty acids n-3 Polyunsaturated fatty acids Calcium Fluoride Magnesium Phosphorus Selenium Biotin Choline 0-12 mo 0-12 mo 0-12 mo 0-12 mo 1-18 y 19-50 y > 50 y Pregnancy and lactation (all ages)
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From page 86... ...
86 TABLE 3-5 Continucci DIETARY REFERENCE INTAKES Nutrient Life Stage Group Group Mean Intake Folate 0-12 mo Yes Niacin 0-12 mo Yes Pantothenic acid 0-12 mo Yes 1-18 y Yes 19-50 y Yes > 50 y Yes Pregnancy (all ages) Yes Lactation (all ages)
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From page 87... ...
Interventions targeted to only those in the lower tail, if successful, would reduce the prevalence of inadequate intakes, while interventions targeted to those in the upper tail would reduce the prevalence of excessive intakes. An intervention to reduce the total variance in usual intakes might reduce the prevalence of both inadequate and excessive intakes.
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From page 88... ...
. Food and nutrition assistance programs target low-income families on the assumption that they are at higher risk of inacloquate intakes.
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