Implementing food-based dietary guidelines for - United Nations ...

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the prevalence of intakes outside the range is high, then
some type of intervention might be considered. The
prevalence that is a cause for concern could vary among
countries or regions, but prevalences greater than 2%
to 3% would be consistent with the use of values like
the INL 98 for other nutrients. Because this type of
assessment is using the AMDR to define cutpoints, it
is essential that the intake distribution be adjusted for
day-to-day variation first.
Pitfalls to avoid
When NIVs are used to assess the intakes of groups,
there are several errors to avoid [18].
In the past, the intakes of groups were evaluated by
comparing the mean intake with the INL 98 and assuming
that the prevalence of inadequacy was low if the
mean was equal to or greater than the INL. However,
it can be shown that this assumption was almost always
incorrect due to the large variation in nutrient intakes.
Because intakes are more variable than requirements,
a substantial proportion of the group still has intakes
below the ANR, even if the mean intake is equal to the
INL 98 . Typically, a prevalence of inadequacy of 25% or
more may be observed in this case. For the prevalence
of inadequacy to be low (less than 5% to 10%), the
mean intake must usually be well above the INL 98 . For
this reason, it is preferable to use either the probability
approach or the cutpoint method to calculate a more
accurate estimate of the prevalence of inadequacy for
the group.
Likewise, it is not helpful to compare the mean intake
of a group with the ANR. If the mean intake is equal to
the ANR, then the prevalence of inadequacy is 50%.
Group intake distributions must be adjusted to
remove the effect of day-to-day variation in intakes.
Unless such an adjustment is made, the prevalence of
inadequacy, the prevalence of excessive intakes, and
the prevalence of intakes outside the AMDR will not
be correctly estimated.
Intakes must be accurately assessed, and the conversion
of food intakes to nutrient intakes must use
appropriate food-composition tables (both of these
topics are covered in more detail below).
Planning nutrient intakes for groups
Goal
The goal of planning the nutrient intakes for groups is
to minimize the prevalence of inadequate intakes and
also to minimize the prevalence of potentially excessive
intakes [3, 19].
Using the cutpoint approach to plan intakes
The cutpoint approach, described above for assessing
the intakes of groups, is also useful for planning
the intakes of groups. To minimize the prevalence of
inadequate intakes, the planner would try to minimize
the proportion of the group with intakes below the
ANR. As noted earlier, the cutpoint approach may be
used for all nutrients with an ANR and a symmetrical
requirement distribution. It also assumes that the
distribution of intakes is greater than the distribution
of requirements, although this assumption is seldom
violated among free-living groups. To minimize the
prevalence of excessive intakes, the planner would try
to minimize the proportion of the group with intakes
above the UNL.
Steps in planning intakes
S. P. Murphy and H. H. Vorster
Planning diets for groups using the cutpoint approach
consists of several steps [3, 19].
1. Decide the exact goals for the planning process. This
involves deciding what prevalences of inadequacy
and prevalences of usual intakes above the UNL are
acceptable. Although it might be considered ideal to
have only 2% to 3% of the group below the ANR or
above the UNL, these may not be practical goals in
some situations.
2. Select the target distribution of usual intakes that
meets these goals. In order to select this target distribution,
it is usually necessary to know the current
intake distribution so that the need for change can be
assessed. In some cases, the intake distribution may
already be acceptable (i.e., very few intakes are below
the ANR or above the UNL). In other situations, it
may be necessary to increase intakes (i.e., move the
current distribution to the right) so that fewer people
would fall below the ANR, or it may be necessary to
decrease intakes (move the current distribution to
the left) so that fewer people are above the UNL.
3. Plan menus or food patterns that achieve these goals
for all of the nutrients of concern. This will usually
require the use of dietary assessment software that
will use an appropriate food-composition table to
calculate the nutrient content of a menu. The goal
might be for the menu to provide nutrient levels at
the midpoint of the target distributions that were
chosen for each nutrient. The foods and amounts
that will actually be consumed, not just those provided
by the menus, should also be considered.
4. Because there are many uncertainties in the planning
process, it is usually essential that the results
be assessed after the menus or food patterns are
implemented. If the planning goals are not met, then
it may be necessary to repeat these steps until the
results are satisfactory.
Planning using the AI
For nutrients with an NIV, such as an AI, intakes should
be planned so that the mean amount consumed by the
group is equal to the AI. The distribution of intakes
does not need to be planned for these nutrients.