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OCR for page 107
7
Examples of
Planning for Groups
SUMMARY
Several applications of group planning are presented in this chap-
ter. Two examples focus on normal group fouling situations where
the distribution of intakes is shifted but the shape of the clistribu-
tion is not explicitly changed. Two examples focus on planning for
heterogeneous groups using a simple and a complex (but theoreti-
cally more correct) nutrient density approach. The final two examples
discuss the problem of planning interventions designed to change
the shape of the usual intake distribution of one or more nutrients
in a targeted population group.
It is often difficult to plan cliets that will achieve exactly the clesireci
effect. Therefore, when planning normal cliets or clietary interven-
tions it is critically important to assess the likely effects not only on
the target group, but also on other groups that would be affected by
the intervention.
Important unpredictable factors such as food preferences, partici-
pation rates in food assistance programs, or population-based edu-
cational programs make the job of an intervention planner very
difficult. Typically, forecasting the effect of an intervention is not
straightforward, and several cycles of planning followed by assess-
ment may be neecleci. The applications clevelopeci in this chapter
are hypothetical.
107
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108
DIETARY REFERENCE INTAKES
INTRODUCTION
Planning diets for population subgroups is carried out in many
diverse settings and thus has multiple and varied applications. Some
of the more visible group-planning applications include planning
diets for institutionalized groups, food and nutrition assistance pro-
grams, food fortification, nutrition education for groups, and mili-
tary food and nutrition planning.
The discussion below provides an in-depth analysis of six specific
planning applications. Examples (1) an assisted living facility for
seniors and (2) school nutrition programs, present the principles
described in Chapter 3 for shifting the distribution of usual intakes.
Examples (3) a group of teen boys, adult men, and adult women
using the simple nutrient density approach and (4) a group of teen
boys, adult men, and adult women using the nutrient density distri-
bution approach, present the approaches described in Chapter 4.
Finally, examples (~) nutrient supplementation and (6) food fortifi-
cation, illustrate how interventions intended to shift the distribu-
tion of usual intakes may also change the shape of the usual intake
distribution. This discussion is not intended to prescribe how these
planning activities should be conducted. Rather, based on the prin-
ciples for group planning developed in Chapters 3 and 4, the dis-
cussion of these examples is intended to present the issues involved
in these planning applications.
The group-planning framework should be applied in pilot situa-
tions before it is adopted for large-scale programs.
PLANNING DIETS IN AN ASSISTED-LIVING FACILITY
FOR SENIOR CITIZENS
An example of planning diets for institutionalized groups is menu
planning for senior citizens who reside in an assisted-living facility.
Menus planned for these institutions usually assume that the resi-
dents have no other sources of foods or nutrients, and thus the
menus are designed to meet all nutrient needs of the residents.
Based on the framework developed in Chapter 3, the goal of menu
planning is to provide meals that supply adequate nutrients for a
high proportion of the residents, or conversely, to ensure that the
prevalence of inadequate intakes are acceptably low among the res-
idents. An important note, and caveat perhaps, is that to fully im-
plement the planning approaches described in this report, data on
usual intakes must be available. Unfortunately, such data are sel-
dom available; planners for these and other institutionalized groups
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EXAMPLES OF PLANNING FOR GROUPS
109
(e.g., prisons, boarding schools) frequently do not collect clietary
intake ciata in order to evaluate their menu planning. It is possible
to generate usual intake ciata on the target population through ciai-
ly food intake records or intake recalls on each incliviclual. Howev-
er, if the facility is large (e.g., more than 100 resiclents), intakes
could be measured on a representative subsample of residents. Us-
ing this technique, two nonconsecutive clays or three consecutive
clays of food intake records or recalls are necessary. Alternatively,
records of amounts served and plate waste ciata for inclivicluals mon-
itoreci, again for a minimum of two nonconsecutive or three con-
secutive clays, can be used. In both cases, ciata should be acljusteci to
remove within-person variability and to obtain the usual nutrient
intake distribution by using procedures such as those clevelopeci by
Nusser and colleagues (1996) or the National Research Council (NRC,
1986~.
Another possibility is to use usual nutrient intake distributions
from another group in which the members are of similar age to the
target group. Ideally, such ciata would also be for a similar (e.g.,
gentler mix, ethnicity) institutionalized population, since the varia-
tion in the distribution of usual intakes is likely to differ among
inclivicluals who live in institutionalized settings and those who do
not. If such comparable usual intake ciata are not available, then
the only option may be to use usual intake distributions from
national surveys such as the Continuing Survey of Food Intakes by
Inclivicluals (CSFII) or the Third National Health and Nutrition
Examination Survey (NHANES III).
From the most appropriate ciata set available as clescribeci above,
the Planner examines the proportion of the group with usual
intakes less than the Estimated Average Requirement (EAR) (for
each of the nutrients for which EARs have been established as an
estimate of the prevalence of inacloquate intakes. If the prevalence
is unacceptably high for one or more nutrients, then intakes need
to be increased. As clescribeci in Chapter 3, to estimate the amount
of the increase for a given nutrient, the difference between the EAR
for that nutrient and the usual intake level corresponding to the
selected percentile of the current usual intake distribution (which
is the chosen acceptable prevalence of inacloquacy) is cletermineci.
The meclian usual intake should be increased by this amount,
assuming the shape of the distribution is not expected to change. It
is crucial to reassess intakes after the change is macle, especially if
the change is large, because it is possible (even likely) that the shape
of the distribution will change.
As an example, consider a planner who is developing a menu for
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DIETARY REFERENCE INTAKES
an assisteci-living facility in which the residents are retired nuns age ci
70 years and above. For this age group, the EAR for vitamin B6 is 1.3
mg/ciay (IOM, 1998a). Assume that no ciata can be located on the
distribution of usual intakes of this group or a similar group, and
that resources are not available to conduct a clietary survey in the
institution. How could the planner proceed to determine the target
intake distribution of vitamin B6 neecleci to attain an acceptable
prevalence of inacloquacy?
Step I. Determine an acceptably Stow prevalence of inadequacy.
For vitamin B6, the EAR was set at a level acloquate to maintain
plasma pyricloxal phosphate levels at 20 nmol/L (IOM, 1998a). This
plasma level is not accompanied by observable health risks, and
thus allows a moderate safety margin to protect against the clevelop-
ment of signs or symptoms of deficiency. This cutoff level was select-
eci recognizing that "its use may overestimate the B6 requirement
for health maintenance of more than half the group" (IOM, 1998a).
For this reason, assume that the planner has cletermineci that a
10 percent prevalence of inadequacy (i.e., 10 percent with intakes
below the EAR) would be an acceptable planning goal.
Step 2. Determine the target usual nutrient intake distribution.
Next, the planner needs to position the intake distribution so the
nutrient intake goals are met. In this example, the planner clecicles
that the prevalence of inacloquacy in the group will be set at 10
percent, and as a result the usual intake distribution of the group
should be positioned such that only 10 percent of the group has
usual intakes less than the EAR. Using the EAR as a cut point for
estimating the prevalence of inadequate intakes builds directly on
the approaches previously clescribeci for assessing intakes (IOM,
2000a).
Because ciata on the usual nutrient intake distributions of the
residents are not available, other sources must be used to estimate
the target usual nutrient intake distribution. Data on the clistribu-
tion of usual clietary intakes of vitamin B6 from CSFII (conclucteci in
1995), NHANES III (conducted between 1988 and 1994), and the
Boston Nutritional Status Survey (conclucteci between 1981 and
1984) are available (IOM, 1998a).i The adjusted percentiles for
~ Caution should be used when selecting data sets. If more recent data sets were
used in this example, it would provide a better reflection of changes in fortifica-
tion levels.
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EXAMPLES OF PLANNING FOR GROUPS
111
women age ci 70 years and above (in the Boston survey, age ci 60
years and above) are summarized in Table 5-1. Assuming there are
no changes in the shape of the distribution, the amount of the shift
can be calculated as the aciclitional amount of the nutrient that
must be consumed to recluce the proportion of the group that is
below the EAR. This is accomplished by determining the difference
between the EAR and the intake at the acceptable prevalence of
inacloquacy (in this case, the 10th percentile of the usual intake
distributions. Examination of the ciata from the three surveys shows
that estimated usual intakes of vitamin B6 vary by as much as 30
percent among the surveys. As a result, the difference between the
EAR of 1.3 mg and the intake at the 10th percentile varies, clepenci-
ing on which ciata are used: for NHANES III the difference is
0.26 mg (1.3 mg - 1.04 mg = 0.26 mg); for CSFII, the difference is
0.42 mg (1.3 mg- 0.88 mg = 0.42 mg), and for the Boston survey,
the difference is 0.7 mg (1.3 mg- 0.6 mg = 0.7 mg). In this exam-
ple, the planner may have no reason to choose ciata from one par-
ticular survey as "more applicable" to his group than another, so he
may estimate target usual nutrient intake distributions using all
three ciata sets. Accordingly, the target intake distributions shift up
by 0.26 ma, by 0.42 ma, and by 0.7 mg using NHANES III, CSFII,
and the Boston survey, respectively. In each case the target usual
nutrient intake distribution would leaci to the accepted prevalence
of inacloquacy. Rather than choosing one set of survey ciata over
another, the planner could simply average the summary measures
clescribeci in the next section.
TABLE 5-1 Selected Percentiles of the Distributions of Usual
Intake of Vitamin B6 from Foods in Older Women
Percentile of Usual Intake Distribution of
Vitamin B6 (mg/day)
Studya n 5th 1 0th 25th 50th 75th 90th 95th
CSFII 221 0.76 0.88 1.11 1.41 1.76 2.12 2.35
NHANES III 1,368 0.92 1.04 1.24 1.53 1.93 2.43 2.76
Boston 281 0.5 0.6 0.7 1.0 1.3 1.6 1.8
a CSFII = Continuing Survey of Food Intakes by Individuals (women > 70 y), NHANES
III = Third National Health and Nutrition Examination Survey (women > 70 y), Boston
= Boston Diet Study (women > 60 y).
SOURCE: IOM (1998a).
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DIETARY REFERENCE INTAKES
Step 3. Select a summary measure of the target usual nutrient intake
distribution to use in planning.
After the planner has estimated a target usual intake distribution,
this information neecis to be operationalizeci into a menu. In order
to do this, the planner will first have to select a summary measure of
the target usual nutrient intake distribution to use as a tool in plan-
ning the menu. The meclian of the target intake distribution is the
most useful; it can be calculated as the meclian of the current intake
distribution, plus (or minus) the amount that the distribution neecis
to shift to make it the target usual intake distribution.
In the current example, although the baseline intakes at the 10th
percentile and the meclian differ among the three surveys, the esti-
mates of the meclians of the target usual intake distributions are
quite similar, as shown in Table 5-2. Assuming that a 10 percent
prevalence of intakes below the EAR was consiclereci acceptable, a
meclian intake for vitamin B6 of 1.7 to 1.8 mg/ciay would be the
planning goal. Accordingly, the menu would neeci to be planned so
that vitamin B6 intakes would be at this level.
Estimates of target nutrient intakes must be converted to esti-
mates of foocis to purchase, offer, and serve that will result in the
usual intake distributions meeting the intake goals. As cliscusseci
previously, designing menu offerings to meet intake targets is a dif-
TABLE 5-2 Identification of the Target Meclian Intakea of
Vitamin B6 to Obtain a 10 Percent Prevalence of
Inacloquacy in Olcler Women
Difference Target
Intake at (EAR- Median Median
EAR 10th Percentile intake at 10th Intake Intake
Studyb (mg/day) (mg/day) percentile) (mg/day) (mg/day)
CSFII 1.3 0.88 0.42 1.41 1.83
NHANES III 1.3 1.04 0.26 1.53 1.79
Boston 1.3 0.6 0.7 1.0 1.70
a The target median intake is estimated by adding the difference between the Estimated
Average Requirement (EAR) and the intake at the acceptable prevalence of inadequacy
(in this case, 10%) to the observed median intake.
b CSFII = Continuing Survey of Food Intakes by Individuals, NHANES III = Third
National Health and Nutrition Examination Survey, Boston = Boston Diet Study.
SOURCE: IOM (1998a).
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EXAMPLES OF PLANNING FOR GROUPS
113
ficult task. Meals with an average nutrient content equal to the
meclian of the target usual nutrient intake distribution may not meet
the planning goals, as inclivicluals in a group tend to consume less
than what is offered and served to them. Thus, the planner might
aim for a menu that offers a choice of meals with a nutrient content
range that includes, or even exceeds, the meclian of the target usual
nutrient intake distribution.
Step 4. Assess implementation of the plan.
Ideally, after the menu has been planned and implemented, a
survey would be conclucteci to assess intakes and determine whether
the planning goal has been attained. This would then be used as
the basis for further planning.
PLANNING MENUS FOR A SCHOOL NUTRITION PROGRAM
Probably the largest group planning application in the United
States is for the nutrition assistance programs sponsored by the U.S.
Department of Agriculture (USDA) . These include the Food Stamp
Program; the Supplemental Nutrition Program for Women, Infants,
and Children; the Child and Adult Care Feecling Program; the
National School Lunch Program (NSLP); the School Breakfast Pro-
gram (SBP); and the Summer Food Service Program.
The NSLP and SBP are federally administered nutrition programs
that operate ciaily in the nation's schools. The primary objective of
these programs is "to safeguard the health and well-being of the
Nation's children" (Richarci B. Russell National School Lunch Act,
42 U.S.C. § 1751 (2) t20021 ~ . The Recommencleci Dietary Allowanc-
es (RDAs) have long formed the basis for fooci-baseci menu plan-
ning in the school nutrition programs. USDA regulations require
that NSLP lunches provide, over time, one-thirci of the RDA for key
nutrients. The goal of the SBP is to provide one-fourth of the RDA.
Findings from two school nutrition clietary assessment studies incli-
cate that, on average, school meals meet or exceed their goals of
offing one-thirci of the RDA for lunch and one-fourth of the RDA
for breakfast (Burgharcit et al., 1995; Devaney et al., 1995; Fox et al.,
2001~.2
2 It is important to note that program regulations are based on the former
RDAs. In addition to the implications of the framework developed for group plan-
ning in this report, the concepts underlying the new RDAs and differences between
the new and old RDAs are important considerations in planning school meals.
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DIETARY REFERENCE INTAKES
Thus, planning for the school nutrition programs has focused on
what is offered in school meals. Since it can be assumed that the
intent of the USDA programs is to protect the intakes of the target
population, the following approach to planning is indicated.
Multiple program objectives for school-baseci meals leaci to im-
portant analytic issues in applying the group-planning framework.
If the objective of the school nutrition programs were simply to
provide meals that would replicate what school children would get
in the absence of the programs, then application of the group-
planning framework cliscusseci in Chapter 3 would not be appropri-
ate. Planners would simply examine the distributions of usual nutri-
ent intake at breakfast and lunch and attempt to provide school
meals that would result in these same usual intake distributions.
Since the school nutrition programs, however, have nutritional
objectives such as safeguarding the health of the nation's children
through the provision of nutritionally acloquate meals in school (as
stated in the language of the federal legislation) then the group-
planning framework clevelopeci in Chapter 3 is relevant and the
question is how best to apply it. Actual application of the framework
is difficult since school meals supply only part of chilciren's usual
ciaily intake, while Dietary Reference Intakes (DRIB) are clefineci on
the basis of usual ciaily intake. USDA has aciciresseci this issue in its
current regulations that specify that school lunches and breakfasts
must provide, on average, one-thirci and one-fourth of the RDA,
respectively. However, the current practice of prorating of the RDA
for meals offered does not imply that it is appropriate to prorate
the DRIs for clietary planning or assessment. The DRIs are a set of
clietary reference values baseci on nutrient intakes over a period of
time and are not meant to be clivicleci into parts of a clay. In acicli-
tion, the proportion of usual intake accounted for by breakfast and
lunch varies considerably among inclivicluals.
Despite these difficult conceptual issues, there are some options
for applying the framework for planning school meals. The first
step is to examine ciaily usual intakes of a representative group of
children covered by the school nutrition programs. Table 5-3 pre-
sents ciata on the usual intakes of vitamin A, vitamin C, and zinc for
boys 9 to 13 years of age from the Third National Health and Nutri-
tion Examination Survey and the Continuing Survey of Food Intakes
by Inclivicluals (IOM, 2000b, 2001~. These ciata suggest a low preva-
lence of inadequacy for the intakes of vitamin C and zinc. For vita-
min A, the estimated prevalence of inacloquacy is ~ to 10 percent.
Suppose planners were interested in using information on the
usual intakes of school children to plan the school meals consumed
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EXAMPLES OF PLANNING FOR GROUPS
TABLE 5-3 Daily Usual Intake of Vitamins A and C and Zinc,
Boys 9 to 13 Years of Age
115
Vitamin A Vitamin C Zinc
(RAE) a (mg) b (mg) b
(EAR= (EAR= (EAR=
Percentile 445 ,ug RAE) 39 ma) 7.0 ma)
1 311 44.1 5.4
2 350 47.9 6.0
3 377 51.7 6.3
5 415 59.2 6.9
10 480 65.9 7.7
25 606 85.6 9.1
50 774 1 19.3 1 1.2
95 1 ,330 334.6 1 8.5
99 1,635 598.3 28.5
Approximate percent < EAR 5-10% 0% 5%
Target median intake 774 + 80
a Usual intake from food only. Taken from the Continuing Survey of Food Intakes by
Individuals and converted to retinal activity equivalents (RAE) using data on vitamin A
and carotenoid intakes. EAR = Estimated Average Requirement.
b Usual intake from food and supplements. Taken from the Third National Health and
Nutrition Examination Survey and adjusted for day-to-day variation using the Iowa State
University method.
SOURCE: IOM (2000b, 2001).
by program participants. As described in Chapter 3, determining
the target usual intake distribution first involves selecting a group
prevalence of inadequacy. In the case of these selected nutrients,
planners are likely to conclude that the usual intakes of vitamin C
and zinc are acloquate, and would therefore plan to maintain cur-
rent intakes. For vitamin A, however, if the acceptable group preva-
lence of inacloquacy is set at 2 to 3 percent rather than the current
~ to 10 percent, planners would aim to shift the usual intake clistri-
bution by about 80 ,ug retinal activity equivalents (RAE) so only 2 to
3 percent are below the EAR, resulting in a target median intake of
854 ,ug RAE.
The next step in applying the group-planning framework is to
clecicle how the school nutrition programs should or could be used
to achieve the targeted usual intake distribution. Two possible
options are (1) to derive the target ciaily usual intake distribution
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DIETARY REFERENCE INTAKES
and prorate the target intakes across meals, or (2) to derive the
target ciaily usual intake distribution, estimate the cleficit in 24-hour
intakes, and plan for intakes from school meals to make up these
cleficits.
The first of these options is consistent with the way in which the
school nutrition programs currently operate, where the amount
offered in the school meals is a specified proportion of the RDAs.
Implementing this option in the case of vitamin A, for example,
would entail prorating the target usual intake distribution, with the
target meclian intake of 854 ,ug RAE, in such a way that a certain
proportion is consumed at breakfast and at lunch.
The second option makes the nutritional objectives of the school
nutrition programs more explicit. Implementing this option involves
planning school breakfasts and lunches such that the distribution
of usual ciaily intakes of participants is the target usual intake clistri-
bution. In this case, the school meals are expected to make up the
cleficit in usual ciaily vitamin A intake of 80 ,ug RAE. The cleficit
could be macle up by planning menus that would acici 80 ,ug RAE to
the meclian intake at breakfast or lunch. This amount could also be
split between the two meals. Tailoring food choices or portion sizes
at the point of service may be impractical. Thus, a methodology of
planning for heterogeneous groups may be neecleci.
In summary, application of the group-planning framework for the
U.S. food and nutrition assistance programs is a complex task that
involves several considerations related to program goals, nutritional
considerations, and program implementation. Like any new para-
cligm, it must first be tested for its feasibility and practicality. The
discussion of the school nutrition programs above is intencleci to
identify the main issues involved in applying the framework and
options to consider in its implementation it is not intencleci to
prescribe how this framework should be implemented in the con-
text of school fouling.
. .
PLANNING DIETS FOR A HETEROGENEOUS GROUP
USING A NUTRIENT DENSITY APPROACH
The examples provided to this point have assumed that planning
is occurring for a group that consists of a single life stage and gender
group or life stage and gentler groups with similar requirements.
Frequently, however, planning will occur for groups that encom-
pass multiple life stage and gentler groups with very different nutri-
ent and energy requirements. Two examples that incorporate the
nutrient density approaches clescribeci in Chapter 4 are provicleci
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EXAMPLES OF PLANNING FOR GROUPS
117
below. The first illustrates the simple nutrient density approach, in
which the target meclian intake for each subgroup is compared to
the average energy neecis of the subgroup. The second example
illustrates the nutrient density distribution approach, which includes
a consideration of the variability of energy and nutrient neecis within
each subgroup.
To compare and contrast the two approaches, both examples con-
sicler the vitamin C intakes of a group consisting of adolescent boys
age ci 14 to 18 years, women age ci 19 to 50 years, and men age ci 19 to
50 years. As in most of the examples in this chapter, ciata used here
are real ciata, in this case collected in the 1994-1996 Continuing
Survey of Food Intakes by Inclivicluals. Intake distributions of vita-
min C and of energy for the three subgroups were acljusteci using
the Iowa State University method (IOM, 2000a; Nusser et al., 1996~.
The estimated usual intake distributions of energy in each of the
subgroups were used as estimates for the distributions of require-
ments of energy. The examples were constructed using the ciata
presented in Table 5-4.
Simple Nutrient Density Approach
Step I. Obtain the target median vitamin C intake for adolescent
boys, adu;tt women, and adu;tt men.
Adolescent Boys. The estimated prevalence of vitamin C inacloquacy
in this particular subgroup of adolescent boys is approximately 19
percent when comparing usual intakes to their Estimated Average
Requirement (EAR) of 63 mg/ciay. Thus, a target vitamin C intake
distribution would be obtained by shifting the baseline usual intake
distribution by an amount sufficient to move the 3rd percentile of
the distribution from its current 31 mg to approximately 63 mg
(assuming that a prevalence of inacloquacy of 2 to 3 percent is what
is desired). By shifting the intakes of vitamin C by 32 mg/day
(EAR- 3rci percentile: 63 - 31 = 32), the target vitamin C intake
distribution is obtained (as was clescribeci in Chapter 3~. In this
target vitamin C intake distribution, the 3rci percentile is now
approximately at the EAR of 63 mg/ciay. The target meclian intake
is now 139 mg/ciay.
Adult Women. The prevalence of inacloquacy among the women in
this example is approximately 33 percent compared to their EAR of
60 ma. To obtain the target vitamin C intake distribution, it is
necessary to shift the distribution by approximately 37 mg/ciay
(EAR- 3rd percentile: 60 - 23 = 37), so that the proportion of
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DIETARY REFERENCE INTAKES
· This process was repeated a total of 400 times in each subgroup
(for each of the 400 vitamin C intakes in each subgroup).
· Then, for each subgroup, the 400 average nutrient density
intakes were used to construct the target vitamin C density intake
distribution.
Adolescent Boys. In the case of boys age ci 14 to 18 years, the target
nutrient density intake distribution has a meclian of 52 mg of vita-
min C/l,OOO kcal, and Sth and 95th percentiles of 26 and 112 ma/
1,000 kcal, respectively.
Adult Women. In this example, the target vitamin C density intake
distribution for women age ci 19 to 50 years has a meclian of 71 ma/
1,000 kcal, a Sth percentile of 42 mg/1,000 kcal, and a 95th percen-
tile of 135 mg/1,000 kcal.
Adult Men. For the subgroup of men age ci 19 to 50 years, the
resulting target vitamin C density intake distribution has a meclian
of 57 mg/1,000 kcal, and Sth and 95th percentiles of 33 and 115 mg /
1,000 kcal, respectively.
Step 3. Compare the target median vitamin C density for each dis-
crete subgroup to set planning goals for the group as a whole.
In this example, the target vitamin C density distribution for women
haci the highest meclian (71 mg/1,000 kcal compared to 57 ma/
1,000 kcal for adult men and 52 mg/1,000 kcal for adolescent boys).
This amount would normally be chosen as the reference nutrient
density intake distribution for the group as a whole, and intakes
would be planned on this basis. The planned menus resulting from
this activity should be checkoci for both total milligrams of vitamin
C and milligrams of vitamin C/l,OOO kcal.
Comparison of the Simple Nutrient Density Approach and the
Nutrient Density Distribution Approach
It is useful to compare the planning results that would be achieved
when using the two nutrient density methods clescribeci above (anci
in Chapter 4~. Recall that for the same group of boys, women, and
men, the meclian of the target nutrient density intake distribution
that would be obtained by simply dividing the target median vita-
min C intake by the mean energy requirement in each of the groups
was 48, 66, and 54 mg/1,000 kcal, respectively. Baseci on these
values, the planner would aim for a target nutrient density intake
distribution in each of the subgroups with a median equal to the
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EXAMPLES OF PLANNING FOR GROUPS
123
highest of the three values, or 66 mg/1,000 kcal. Using this method,
which floes not take into account the distribution of energy require-
ments in the group, results in a prevalence of vitamin C inacloquacy
of approximately 8 to 9 percent for the women in the group (for
adolescent boys and men the resulting intakes would be acloquate
for all inclivicluals). In contrast, using the nutrient density clistribu-
tion approach results in a projected prevalence of inacloquacy of
approximately 2 to 3 percent for the women, and essentially zero
for the men and adolescent boys. Because the nutrient density clis-
tribution approach accounts for variability in energy intakes, it is
more likely to achieve planning goals.
INTERVENTIONS THAT MAY CHANGE
THE SHAPE OF THE INTAKE DISTRIBUTION:
NUTRIENT SUPPLEMENTATION
Some planning applications involve interventions that aim to
mollify food or nutrient intakes. One way to mollify nutrient intakes
when a fooci-baseci approach is not possible is to incorporate use of
a nutrient supplement within a group. If every incliviclual in the
group consumed the identical supplement every clay, the clistribu-
tion of usual intakes would simply shift up, with no change in shape,
by the close of the supplement. In practice, however, all inclivicluals
in a group may not take the supplement on a regular basis, and,
among those who do take it, the close may not be constant. As a
result, misleacling conclusions and practices may result if uniform
supplement usage is assumed.
As an example, suppose a planner wished to recluce the preclicteci
prevalence of zinc inacloquacy among a group of free-living teenage
girls through the use of a supplement. The first step would be to
examine the current intake distribution. Let us assume that the
group of teenage girls being targeted is similar to the sample of
girls age ci 14 to 18 years surveyoci by the Third National Health and
Nutrition Examination Survey (NHANES III), so that ciata from
NHANES III can be used to estimate the current intake clistribu-
tion. Participants in NHANES III are free-living and have not been
the target of any national public health intervention regarding the
use of zinc supplements. Table 5-5 presents information on the clis-
tribution of usual intake of zinc from foocis (acljusteci for within-
person variation) and from supplements. The EAR for zinc in girls
aged 14 to 18 years has been set at 7.3 mg/ciay. As shown in
Table 5-5, more than 25 percent of teen girls haci inacloquate usual
intake of zinc from food alone. If the acceptable group risk of inaci-
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TABLE 5-5 Estimated Usual Zinc Intake Distribution for Girls,
14 to 18 Years of Age (mg/day)
Percentile of Zinc from
Usual Intake Foods
Zinc from
Supplements Total Zinca
1 4.0 0.83 3.9
3 4.7 0.9 4.8
5 5.1 1.0 5.2
10 5.8 1.0 5.8
25 7.1 2.5 7.2
50 8.8 8.0 9.0
75 10.9 15.0 11.6
90 13.2 15.0 13.8
95 16.4 37.5 16.0
99 18.6 45.5 26.6
Sample size 949 48 949
Mean 9.27 9.75 9.82
a Because only 48 of the 949 girls used supplements containing zinc, total zinc intake
does not equal the sum of the zinc intakes from food and supplements.
SOURCE: IOM (2001).
equacy were set at 3 percent, then the 3rci percentile of usual intake
should be increased to the level of the Estimated Average Require-
ment (EAR). That is, the 3rci percentile value of 4.7 in Table 5-5
should increase to 7.3, an increase of 2.6 ma. Assuming that the
usual intake distribution floes not change its shape, the meclian
intake would be the existing meclian intake + 2.6 mg (8.8 mg + 2.6
mg = 11.4 mg). This new usual intake distribution could be achieved
if everyone took a supplement containing 2.6 mg of zinc.
Before recommencling consumption of a supplement containing
2.6 mg of zinc, however, it is important to determine current sup-
plement use. Accordingly, the next step is to examine the reported
use of zinc supplements and the computed distribution of intakes
from both sources, which are shown in Table 5-~. Note that only 48
of the 949 teen girls in the survey reported taking a zinc supple-
ment (approximately ~ percent), so including supplements floes
not affect the total intake for most participants. Indeed, the distri-
bution of total zinc intake differs primarily in the upper percentiles,
with very little change in the lower percentiles. The third percentile
increases only 0.1 mg/day, from 4.7 to 4.8 mg/day. Thus, there is
almost no effect of current use of zinc supplements on the preclicteci
prevalence of inacloquacy. The increase that is neecleci to recluce
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EXAMPLES OF PLANNING FOR GROUPS
125
the prevalence to 3 percent is now 2.5 mg/ciay (7.3 - 4.8) versus 2.6
mg/ciay when food alone is consiclereci.
In theory, planners could develop an education intervention that
recommencleci that teen girls consume a supplement that provides
2.5 mg of zinc/day. Special supplements providing this level of
intake could even be marketed. However, several observations
regarding supplement usage patterns in free-living populations are
important to highlight:
· Although the average supplement provicleci 9.75 mg of zinc, the
change in the meclian intake of zinc, when acicling in supplement
use, was only 0.2 mg (9.0 mg- 8.8 mg).
· Although the meclian intake of zinc increased by 0.2 mg when
supplements were inclucleci, the magnitude of the change at the
3rci percentile was only 0.1 ma.
· The prevalence of inacloquate intake of zinc still exceeds 25
percent, even when intake from currently consumed supplements
is acicleci to the intake from food.
· As is usually the case, supplement usage was not uniform across
this group of inclivicluals. Teen girls with higher intakes of zinc from
food were more likely to take a supplement and perhaps more likely
to take a higher-close supplement.
Thus, supplement use by a free-living population may not achieve
the planner's goals, and the challenge is to determine how to either
shift the whole distribution by 2.5 mg/ciay or to increase the use of
supplements or zinc-rich foods by individuals in the lower percen-
tiles. If an aciclitional supplement of 2.5 mg/ciay of zinc was clistrib-
uteci and consumed by the entire population, then the distribution
would shift as clesireci. As the ciata in Table 5-5 illustrate, it may take
an intensive intervention to achieve this goal.
An alternative approach is to ensure supplement use by those in
the lower percentiles. This might be possible if there are character-
istics that would identify inclivicluals with low intakes (such as
income level or age). Such interventions to increase supplement
use are likely to be more successful in a confined population (where
supplement use could be monitored than in a free-living one.
The important conclusion from this example of planning is that
an intervention to change usual intakes through supplementation
can be difficult to design and implement. In a free-living popula-
tion, not every person can be expected to consistently take a supple-
ment (or a given food or food group rich in a specific nutrient),
and interventions in such a group may be expected to change both
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DIETARY REFERENCE INTAKES
the location and shape of the usual intake distribution. It is impor-
tant to unclerstanci the patterns and predictors of supplement use
in order to model and plan such interventions. Simply assuming
uniform use of a supplement in free-living populations would likely
result in a failure to achieve the planning goals.
FOOD FORTIFICATION
Fortification is often seen as a potentially desirable public health
measure that could achieve an increased intake of specified nutri-
ents without changes in food consumption practices or compliance
with specific nutrient supplement usage. Historically, mandatory
fortification programs have been applied in many countries as a
means to aciciress particular public health concerns. In these pro-
grams, public health authorities determine both the food vehicles
and levels of fortification, and only fortified versions of the selected
foocis are permitted on the market. One such example is the man-
ciatory fortification of table salt with iodine in Canada, a measure
undertaken to recluce iodine deficiency in the population. Alterna-
tively, food fortification programs may be voluntary, with food man-
ufacturers having the option of Hilling particular nutrients (some-
times within prescribed limits) to foocis, but not being required to
do so. One example of this approach is the fortification of orange
juice with calcium; because the program is voluntary, it is possible
to purchase orange juice with or without calcium acicleci. Regula-
tions on food fortification differ between Canada and the United
States, with voluntary fortification permitted in the United States.
Regardless of whether fortification is mandatory or voluntary, if it
is intencleci to achieve public health goals, then it is often necessary
to "target" the fortification. Such targeting could be accomplished
by selecting only foocis for fortification that are used exclusively or
in substantially greater amounts by the group targeted by a fortifica-
tion program, or by mounting an educational program to promote
the use of specific fortified foocis by the target group.
Fortification, however, also carries the potential for detrimental
effects. Fortification of foocis might increase nutrient intakes to
excessive levels among those persons who have high intakes of the
fortified food or those who already have high intakes of the nutri-
ent and then consume the newly fortified food. Minimally con-
trolleci fortification of foocis, even at low levels in incliviclual foocis,
can have unexpected effects, ranging from negligible benefits to
public health concerns about potentially detrimental high intakes.
Further, unless fortified foods reach only the target group (unusual
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EXAMPLES OF PLANNING FOR GROUPS
127
in practice, except for infant foocis), it is possible that the risk of
detrimental effects will appear in other sectors of the population
(i.e., nontarget groups). Because of the range of potential effects
that can accompany fortification programs, both beneficial and
detrimental, the potential impact of proposed fortification is usually
examined before implementation.
In general, no simple method can be used to predict the effects of
fortification. Fortifying foocis with nutrients will have impacts on
the nutrient intakes of those who consume the fortified foocis and
will not have impacts on those who do not consume them. Further,
the degree of impact clepencis not only on the level of the nutrient
acicleci, but also on the distribution of usual intakes of the food. In
recent years, predicting the effect of fortification has been compli-
cateci in the United States by introduction of food products forti-
fieci with a nutrient while the evaluation of the neeci for fortifica-
tion is still in progress. Thus, it is difficult to anticipate changes in
the usual intake distribution of the nutrient when even changes in
the amount of the nutrient in the food supply are almost impossible
to predict. A more extencleci discussion on the issue of voluntary
fortification is presented in Appendix D.
The approach presented below involves mocleling and estimating
the effects of a mock fortification effort by using ciata on foocis and
nutrients consumed and then calculating the change in nutrient
intake after the foocis are fortified. The preclicteci benefits and risks
associated with the fortification can be assessed through application
of assessment methods baseci on the Estimated Average Require-
ment (EAR) and Tolerable Upper Intake Level (UL) (IOM, 2000a).
Such an approach was utilized by Lewis and colleagues (1999) to
examine the impact of folate fortification of cereal-grain products
in the United States if increased fortification of foocis was manciateci.
A similar approach is illustrated below for the hypothetical aciclition
of vitamin A to fluici milk. For simplicity, this example assumes that
only one food will be fortified with vitamin A. As was cliscusseci
earlier, this assumption is unlikely to hold when voluntary fortifica-
tion of foocis with vitamin A is permitted.
Addition of Vitamin A to Fluid Milk
Two levels of requirements for vitamin A have been established
with different functional endpoints in mind (IOM, 2001~. For adult
women, the EAR for prevention of functional deficiency of vita-
min A is 300 ,ug retinal activity equivalents (RAE)/ciay while the
EAR to establish and maintain desirable levels of liver vitamin A
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DIETARY REFERENCE INTAKES
stores has been set at 500 ,ug RAE/ciay. For adult women 19 to 50
years of age, examination of the 1994-1996 CSFII (USDA/ARS,
1997) ciata suggests that about 15 percent have intakes below 300 ,ug
RAE/ciay and hence have intakes apparently inacloquate to meet
their own functional requirements. The same ciata suggest that about
44 percent may have intakes inacloquate to provide minimal stores
of vitamin A. These descriptors of a potential problem may moti-
vate planning interventions to raise vitamin A intakes in this target
group, although planners would also obtain other types of ciata (e.g.,
biochemical or clinical outcome information such as incidence of
night blinciness) before proceeding with an intervention.
Suppose that in order to increase vitamin A intake by adult
women, a fortification program is consiclereci that acicis vitamin A to
all fluici milk. In the United States milk is frequently fortified with
vitamin A, but it is not required. This example assumes that no
fortification is currently taking place.
Baseci on ciata from the CSFII (USDA/ARS, 1997), Table 5-6 illus-
trates the preclicteci impact of this fortification on the distribution
of total vitamin A intake of adult women. Total intake equals reported
TABLE 5-6 Impact of the Aciclition of Vitamin A to Milk on
the Expected Distribution of Total Vitamin A Intake in
Women 19-50 Years of Age
Level of Addition of Vitamin A (as Retinyl Ester) to Fluid Milk
(Pg./ 100 ml)
Percentile
of Intake 0 50 100 150 200 250 300
1 135 138 140 143 145 147 149
5 225 238 247 253 259 268 276
10 272 287 298 308 319 327 337
25 368 398 421 445 465 484 505
50 542 592 635 670 711 747 787
75 785 872 964 1,083 1,151 1,245 1,333
90 1,150 1,259 1,389 1,549 1,679 1,811 1,954
95 1,390 1,560 1,715 1,915 2,084 2,234 2,411
99 2,026 2,154 2,372 2,573 2,777 3,067 3,325
NOTE: n = 2,325 women. In this example, the amount by which vitamin A increases
reflects the initial fluid milk consumption of those in the various percentile groups. For
example, those in the 1st percentile drink little milk, so their vitamin A intake increases
only slightly as the level of addition of vitamin A to milk increases. In contrast, those in
the 99th percentile, who drink much more milk, have a much greater increase.
SOURCE: USDA/ARS (1997) as reported in IOM (2001).
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EXAMPLES OF PLANNING FOR GROUPS
129
intake of vitamin A plus the increase that would come from con-
suming fortified milk. It is possible to determine the theoretical
increase because the CSFII database can be clisaggregateci to cleter-
mine the amount of milk consumed by each incliviclual. Thus, the
amount of the increase in vitamin A intake will reflect the amount
of milk consumed: those women who consume large amounts of
fluici milk will increase their intake substantially, while those who
consume little or no fluici milk will not increase their intake.
Table 5-7 provides some information on the likely benefits and
potential risks of this fortification. Baseci on the results for adult
women, Billing vitamin A to fluici milk could be expected to have
beneficial impacts by raising intakes without a major concern about
possible detrimental effects. That is, as the level of fortification
increases, the prevalence of usual intake of vitamin A less than the
EAR to prevent night blindness (300 ,ug RAE) declines from
approximately 15 percent at no fortification to approximately 7 per-
cent at a fortification level of 300 ,ug of retinol/100 mL of milk. The
prevalence of usual intake less than the EAR for maintaining stores
(500 ,ug RAE) declines from 44 percent at no fortification to 24
TABLE 5-7 Apparent Benefits and Potential Risks Associated
with the Aciclition of Vitamin A to all Fluid Milk as a Function
of Level of Aciclition, Women 19-50 Years of Age
Prevalence of Inadequate Intakesb
(below the EAR)
Prevalence of
Potentially Excessive
IntakesC
Level of Additiona % UL
(Pg/100 ml) (300 ,ug RAE) (500 fig RAE) (3,000 ,ug)
0 (baseline) 14.6 44.3 0.0
50 12.1 38.9 0.0
100 10.2 35.6 0.1
150 8.8 33.3 0.1
200 8.0 29.9 0.2
250 7.6 28.8 0.3
300 6.9 24.3 0.7
NOTE: n = 2,325 women.
a Added as a retinyl ester.
b Based on total vitamin A intake as ,ug of retinal activity equivalents (RAE). EAR
Estimated Average Requirement.
c Based on preformed vitamin A only. UL = Tolerable Upper Intake Level.
SOURCE: USDA/ARS (1997).
=
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DIETARY REFERENCE INTAKES
percent at a fortification level of 300 ,ug of retinol/100 ml of milk.
In contrast, as the level of fortification increases, the prevalence of
usual intake above the UL increases only slightly from 0 to 0.7 per-
cent. On the basis of this evidence only, the decision to fortify milk
with vitamin A would seem a worthwhile endeavor.
Other subgroups, however, may not have the same benefits or
risks at that level of vitamin A fortification. Table 5-8 shows the
impact of this fortification of fluici milk for boys 9 to 13 years of age.
In this case, the prevalence of inacloquate vitamin A intake without
fortification (at baseline) is lower than for adult women. With forti-
fication, the prevalence of inacloquate intakes baseci on maintain-
ing stores (EAR = 445 ,ug RAE for this age group) cleclines from
about 11 percent to 3.5 percent. Since there is very little prevalence
of inacloquate intake of vitamin A baseci on preventing night blinci-
ness (EAR = 230 ,ug RAE for this age group) without fortification,
the aciclition of more vitamin A to milk would have a negligible
effect on prevalence of this criterion of inacloquate intake. On the
other hanci, the potential detrimental effect with fortification is
TABLE 5-8 Apparent Benefits and Potential Risks Associated
with the Aciclition of Vitamin A to all Fluid Milk as a Function
of Level of Aciclition, Boys 9-13 Years of Age
Prevalence of Inadequate
Intakesb (below the EAR)
Prevalence of
Potentially
Excessive IntakesC
Level of Additiona % UL
,ug/100 ml (230 ,ug RAE) (445 ,ug RAE) (1,700 ,ug)
0 (baseline) 0.5 11.1 0.9
50 0.3 8.2 2.6
100 0~3 7.0 5~9
150 0.3 5.6 12.2
200 0.3 4.5 19.0
250 0.3 4.2 30.0
300 0.3 3.5 37.8
NOTE: n= 574 boys.
a Added as a retinyl ester.
b Based on total vitamin A intake as ,ug of retinal activity equivalents (RAE). EAR =
Estimated Average Requirement.
c Based on preformed vitamin A only. UL = Tolerable Upper Intake Level.
SOURCE: USDA/ARS (1997).
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EXAMPLES OF PLANNING FOR GROUPS
131
high, as shown by increasing percentages with usual intake above
the UL as the level of fortification increases. Specifically, with no
fortification, the prevalence of usual intakes above the UL for this
age group is approximately 1 percent, while at a fortification level
of 300 ,ug of retinol/100 mL of milk, the prevalence of usual intakes
above the UL would increase to 38 percent. The reason for these
differential impacts for adult women and boys 9 to 13 years of age is
that the latter group has a higher initial intake of vitamin A, and an
overall higher consumption of the vehicle chosen for fortification-
milk.
By combining the analyses for adult women and boys 9 to 13 years
of age, the relationship between the potential benefits to women
and the potential risks to adolescent boys of fortifying milk at the
various levels is clemonstrateci. Figure 5-1 summarizes the benefits
to adult women by the declining percentage with inacloquate intake
and the increasing potential risk to boys 9 to 13 years of age by the
increasing percentage over the UL. Baseci on these results, planners
would have to consider the preclicteci potential risk to boys 9 to 13
years of age and the preclicteci benefits to the target group of adult
women before reaching a decision on whether to fortify and at what
50 -
40 -
30-
ct
-
ct
~ 20-
Cal
10-
O-
Benefit to women: preserve liver stores
-
Benefit to women: preserve function
-
ma_ _
~—
l
by__
.~
-
Risk to boys of excess
-
-
-
-
~_
_
0 50 100 150 200 250 300
Level of Addition (,ug/100 ml)
- 50
- 40
o
-30 ~
s
- 20 ,c
Cal
-
- 10
- o
FIGURE 5-1 Projected benefits and potential risk associated with the addition of
vitamin A to fluid milk. UL = Tolerable Upper Intake Level.
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DIETARY REFERENCE INTAKES
amount. Of course, this exercise should be repeated for other sub-
groups of the population before final decisions are macle.
When only a few foocis are involved in compulsory fortification,
regulatory agencies run mock fortification studies (like the vitamin
A example above) and weigh the expected benefits and potential
risks associated with different levels of fortification. However, with
voluntary fortification such as what is currently the practice in the
United States, as the number of fortified foocis increases, it becomes
extremely difficult to run meaningful mock fortification scenarios.
In aciclition, it has not been possible to keep food composition ciata-
bases current with regard to branci-specific fortified foocis, and not
all nutrient composition databases in the United States are clesigneci
to do so. Food composition databases in the United States used in
national surveys usually reflect the average composition of foocis
that are available in the market, with varieties or brancis weighted
by general market share. Thus, it is difficult to investigate the effect
of voluntary fortification of specific brancis of foocis unless all brancis
within a category are fortified. More cletaileci survey ciata, as well as
more specific food composition tables, are neecleci for investigation
of branci-specific fortification.
Planning Fortification: General Conclusion and Recommendation
The principal conclusion drawn from this fortification applica-
tion is the importance of examining the potential impacts on all
groups notjust on the targeted subgroups that have a higher than
clesireci prevalence of inacloquate intakes without fortification. It is
recommended that a modeling approach, such as that presented
here, be conclucteci prior to any major introduction of fortification.
Representative terms from entire chapter:
intake distribution
