This appendix contains information on how schoolchildren’s dietary intakes compare with Estimated Average Requirements and data and a description of the use of the probability method to calculate the Target Median Intake for iron for adolescent females.
Table I-1 Estimated Average Requirements (EARs) for Schoolchildren and Reported Nutrient Intakes at the 5th Percentile and Median by Age-Grade Group and Gender
Table I-2 Iron Intake Distribution for 14–18-Year-Old Female Participants (mg/d)
Table I-3 Iron Intake Distribution for 11–13-Year-Old Female Participants (mg/d)
Table I-4 Iron Requirement Distribution for 14–18-Year-Old Females (mg/d)
Table I-5 Iron Requirement Distribution for 9–13-Year-Old Females (mg/d)
Table I-6 Estimated Iron Requirement Distribution for 11–13-Year-Old Females (mg/d)
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 285
Appendix I
Dietary Intake Data and Calculation
of the Target Median Intake for Iron
This appendix contains information on how schoolchildren’s dietary
intakes compare with Estimated Average Requirements and data and a
description of the use of the probability method to calculate the Target
Median Intake for iron for adolescent females.
LIST OF TABLES
• Table I-1 Estimated Average Requirements (EARs) for Schoolchil-
dren and Reported Nutrient Intakes at the 5th Percentile and Median by
Age-Grade Group and Gender
• Table I-2 Iron Intake Distribution for 14–18-Year-Old Female Par-
ticipants (mg/d)
• Table I-3 Iron Intake Distribution for 11–13-Year-Old Female Par-
ticipants (mg/d)
• Table I-4 Iron Requirement Distribution for 14–18-Year-Old Fe-
males (mg/d)
• Table I-5 Iron Requirement Distribution for 9–13-Year-Old Fe-
males (mg/d)
• Table I-6 Estimated Iron Requirement Distribution for 11–13-
Year-Old Females (mg/d)
OCR for page 285
SCHOOL MEALS
TABLE I-1 Estimated Average Requirements (EARs) for Schoolchildren
and Reported Nutrient Intakes at the 5th Percentile and Median by Age-
Grade Group and Gender
6–10 years 11–13 years 14–18 years
Males Females Males Females Males Females
Nutrient (n=295) (n=317) (n=342) (n=342) (n=506) (n=512)
Protein (g/kg/d)
EAR 0.76 0.76 0.76 0.76 0.73 .71
0.7 0.5
Intake at 5th 1.5 1.5 1.1 0.9
Median Intake 2.4 2.3 1.8 1.4 1.5 1.1
Vitamin A (µg RAE/d)
EAR 343 333 445 445 630 485
373 236 280 175
Intake at 5th 352 367
Median Intake 631 614 689 529 635 439
Vitamin C (mg/d)
EAR 29 29 39 39 63 56
24 32 19
Intake at 5th 36 48 43
Median Intake 83 90 92 73 90 67
Vitamin E (mg αT/d)
EAR 7.2 7.2 9.0 9.0 12.0 12.0
4.9 3.4 4.1 2.6 4.2 2.6
Intake at 5th
Median Intake 6.0 5.2 6.5 5.4 7.2 5.3
Thiamin (mg/d)
EAR 0.6 0.6 0.7 0.7 1.0 0.9
0.7
Intake at 5th 1.0 1.0 1.2 0.7 1.1
Median Intake 1.6 1.5 1.7 1.4 1.9 1.3
Riboflavin (mg/d)
EAR 0.6 0.6 0.8 0.8 1.1 0.9
0.8
Intake at 5th 1.4 1.4 1.6 1.0 1.4
Median Intake 2.3 2.2 2.5 2.0 2.6 1.7
Niacin (mg/d)
EAR 7.2 7.2 9.0 9.0 12.0 11.0
9.6
Intake at 5th 13.9 12.9 15.1 10.8 18.1
Median Intake 20.5 19.9 22.5 19.6 27.1 18.2
Vitamin B6 (mg/d)
EAR 0.6 0.6 0.8 0.8 1.1 1.0
0.7
Intake at 5th 1.2 1.0 1.2 0.8 1.5
Median Intake 1.7 1.6 1.9 1.6 2.2 1.4
Folate (µg DFE/d)
EAR 196 196 250 250 330 330
219
Intake at 5th 310 322 415 228 361
Median Intake 553 536 640 477 647 442
Vitamin B12 (µg/d)
EAR 1.2 1.2 1.5 1.5 2.0 2.0
1.4
Intake at 5th 2.5 2.5 3.9 2.0 3.0
Median Intake 5.1 4.6 6.0 4.5 6.1 3.8
Iron (mg/d)
5.7a
EAR 4.8 4.7 5.9 7.7 7.9
6.0
Intake at 5th 8.5 8.6 10.9 6.9 10.6
Median Intake 14.6 13.9 16.2 13.3 17.9 11.8
OCR for page 285
APPENDIX I
TABLE I-1 Continued
6–10 years 11–13 years 14–18 years
Males Females Males Females Males Females
Nutrient (n=295) (n=317) (n=342) (n=342) (n=506) (n=512)
Magnesium (mg/d)
EAR 146 146 200 200 340 300
181 134 182 110
Intake at 5th 165 172
Median Intake 253 236 266 223 291 206
Zinc (mg/d)
EAR 5.2 5.2 7.0 7.0 8.5 7.3
5.9 8.0 4.7
Intake at 5th 6.9 6.5 8.7
Median Intake 11.1 10.0 12.4 9.9 14.2 9.1
Phosphorus (mg/d)
EAR 665 665 1,055 1,055 1,055 1,055
636 971 597
Intake at 5th 874 917 1082
Median Intake 1,376 1,281 1,483 1,171 1,622 1,087
NOTES: αT = α-tocopherol; d = day; DFE = dietary folate equivalents; g = gram; kg = kilogram;
mg = milligrams; n = sample size; RAE = retinol activity equivalents; µg = micrograms.
aThe committee used a reference value of 7.5 mg for girls ages 11–13 years, as explained
under “Iron Status” in Chapter 3.
SOURCES: Weighted tabulations of data from the third School Nutrition Dietary Assess-
ment study (SNDA-III) (USDA/FNS, 2007a); adapted from Table VI.16 in Volume II and
tables in Appendix J to Volume II. Dietary intake data (24-hour recalls) were collected dur-
ing the 2004–2005 school year and do not include intakes from dietary supplements (e.g.,
multivitamin-multimineral preparations). The personal computer version of the Software for
Intake Distribution Estimation (PC-SIDE; ISU, 1997) was used to estimate the usual nutri-
ent intake distributions and the percentage of children with usual intakes below the EARs.
The EARs used in the analysis were from the DRI reports (IOM, 1997, 1998, 2000a, 2001,
2002/2005). EARs shown for the males and females ages 6–10 years are weighted averages
of two DRI age groups. Bolded numbers indicate that intake at the 5th percentile is below
the EAR.
CALCULATION OF THE TARGET MEDIAN INTAKES FOR IRON
The Probability Approach for Calculating the Prevalence of Inadequacy
The distribution of iron requirements has been estimated using facto-
rial models based on component losses and the deposition of iron. Since
it was expected that the distribution was not normal, the distribution was
estimated using simulation of a population of 100,000 individuals (IOM,
2000b, p. 569). A consequence of the nonnormality of the requirement
distribution is that the Estimated Average Requirement (EAR) cut-point
method does not provide a sufficiently accurate estimate of the prevalence
of inadequacy, particularly for menstruating women. The recommended al-
ternative is to use the probability approach (IOM, 2000b, pp. 205–208).
The basic idea underlying the probability approach is most easily
OCR for page 285
SCHOOL MEALS
understood in terms of a large population of individuals with known in-
takes. For each individual, the probability of inadequacy is calculated from
the requirement distribution (i.e., the probability that the requirement is
greater than the individual’s intake). These probabilities are averaged over
all individuals in the population to give the prevalence of inadequacy.
The two inputs for the calculation are the intake distribution and the
requirement distribution. Let FR(r) and FI(i) denote the cumulative distri-
bution functions for requirement and intake, respectively. The prevalence
of inadequacy is the probability that the intake, I, is less than or equal to
the requirement, R, that is, P(I ≤ R). In terms of the cumulative distribu-
tion functions, we have the following expression for the prevalence of
inadequacy:
P(I ≤ R) = ∫ P(I ≤ R I = i)dFI (i) = ∫ 1 − FR (i) dFI (i)
Let x1 ≤ x2 ≤ L ≤ xn denote an ordered set of intakes that span the
range of the distribution. The probability of inadequacy can be approxi-
mated by
n − 1 1 − F (x ) + 1 − FR (x j )
P(I ≤ R) ≈ ∑
j +1 F (x ) − F (x )
R
J
j +1
2 I I
j =1
Intake and Requirement Distributions
Calculations using this method were performed for 14–18-year-old
females and 11–13-year-old females. The intake distribution was based on
National School Lunch participants included in the third School Nutrition
Dietary Assessment study. For the 14–18-year-old female participants, the
intake distribution is in Table I-2.
For the 11–13-year-old female participants, the intake distribution is
shown in Table I-3.
The requirement distributions for iron are given by IOM (2001). For
14–18-year-old females, the requirement distribution is shown in Table I-4.
For 11–13-year-old females, the requirement distribution is not available
but the requirement distribution is given for 9–13-year-old females (see
Table I-5).
Because the 11–13-year-old females will have a higher percentage of
menstruating females than the 9–13-year-old females, the iron requirements
OCR for page 285
TABLE I-2 Iron Intake Distribution for 14–18-Year-Old Female Participants (mg/d)
Percent 0.01 0.025 0.05 0.08 0.10 0.13 0.15 0.18 0.20 0.23 0.25 0.28 0.30 0.33
Intake 5.26 6.13 6.96 7.56 8.05 8.47 8.86 9.22 9.55 9.88 10.2 10.5 10.8 11.1
Percent 0.35 0.375 0.40 0.43 0.45 0.48 0.50 0.53 0.55 0.58 0.60 0.63 0.65 0.68
Intake 11.4 11.7 12.0 12.2 12.5 12.8 13.1 13.4 13.8 14.1 14.4 14.8 15.1 15.5
Percent 0.70 0.725 0.75 0.78 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 0.99
Intake 15.9 16.3 16.8 17.3 17.8 18.4 19.1 19.9 20.8 22.0 23.6 26.3 29.7
NOTE: mg/d = milligrams/day.
TABLE I-3 Iron Intake Distribution for 11–13-Year-Old Female Participants (mg/d)
Percent 0.01 0.025 0.05 0.08 0.10 0.13 0.15 0.18 0.20 0.23 0.25 0.28 0.30 0.33
Intake 5.61 6.50 7.37 7.99 8.49 8.93 9.32 9.69 10.0 10.4 10.7 11.0 11.3 11.6
Percent 0.35 0.375 0.40 0.43 0.45 0.48 0.50 0.53 0.55 0.58 0.60 0.63 0.65 0.68
Intake 11.9 12.2 12.5 12.8 13.1 13.4 13.7 14.0 14.3 14.7 15.0 15.3 15.7 16.1
Percent 0.70 0.725 0.75 0.78 0.80 0.83 0.85 0.88 0.90 0.93 0.95 0.98 0.99
Intake 16.5 16.9 17.4 17.9 18.4 19.0 19.7 20.5 21.4 22.6 24.2 26.9 30.3
NOTE: mg/d = milligrams/day.
OCR for page 285
TABLE I-4 Iron Requirement Distribution for 14–18-Year-Old Females (mg/d)
0
Percentile 0.025 0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.95 0.975
Requirement 4.63 5.06 5.61 6.31 6.87 7.39 7.91 8.43 9.15 10.03 11.54 13.08 14.8
NOTE: mg/d = milligrams/day.
TABLE I-5 Iron Requirement Distribution for 9–13-Year-Old Females (mg/d)
Percentile 0.025 0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.95 0.975
Requirement 3.24 3.6 4.04 4.59 4.98 5.33 5.66 6.0 6.36 6.78 7.38 7.88 8.34
NOTE: mg/d = milligrams/day.
TABLE I-6 Estimated Iron Requirement Distribution for 11–13-Year-Old Females (mg/d)
Percentile 0.025 0.05 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.95 0.975
Requirement 4.18 4.61 5.16 5.86 6.42 6.94 7.46 7.98 8.70 9.58 11.1 12.6 14.35
NOTE: mg/d = milligrams/day.
OCR for page 285
APPENDIX I
for 11–13-year-old females are higher than those for 9–12-year-old females
and the shape of the distribution is likely to be skewed to the right, as is the
distribution for 14–18-year-old females. Therefore, an estimated require-
ment distribution for 11–13-year-old females was computed by setting the
EAR at 7.46 (versus 5.66 for 9–13-year-old females and 7.91 for 14–18-
year-old females) and using the shape of the distribution for 14–18-year-old
females. Thus, the estimated requirement distribution for 11–13-year-old
females was obtained by subtracting 0.45 (7.91–7.46) from each of the per-
centiles of the requirement distribution for 14–18-year-old females. Table
I-6 presents the resulting distribution.
Modeling the Distribution
Normal quantile plots indicated that the intake distribution for 14–18-
year-old females is skewed to the right. Taking logs and making similar
plots suggested that the distributions were fairly close to lognormal but
were slightly less skewed. A cubic equation gave a very accurate descrip-
tion of the relationship between the normal score and log iron seen in the
normal quantile plot for log iron. Therefore, the cumulative distribution
for intake was determined by an equation of the form
FI (i) = Φ–1 (Constant + A log (i) + B log (i)2 + C log (i)3)
where the constant, A, B, and C were estimated by least-squares. This
cubic function is used to compute the cumulative distribution for the iron
intake distribution needed for the probability approach for calculating the
prevalence of inadequacy. The modeled percentiles agreed with reported
percentiles exactly when rounded to the reported percentiles. The modeled
intake distribution for 14–18-year-old females is
FI (i) = Φ −1(–5.898954 + 1.926415log(i) + 0.124009log(i)2 + 0.006763log(i)3 )
l
where Φ–1 is the inverse of the normal cumulative distribution function and
i is the requirement. The situation was similar for the intake distribution of
11–13-year-old females. The modeled intake distribution is
FI (i) = Φ −1(–6.050645 + 1.888511log(i) + 0.148162log(i)2 +0.005342log(i)3 )
l
The requirement distributions were somewhat more skewed. The
method used for the intake distributions gave similarly accurate fits. For
14–18-year-old females, the modeled requirement distribution is
OCR for page 285
SCHOOL MEALS
FR (r) = Φ −1(–2.481062–4.568515log(r) + 4.384396log(r)2 –0.771171log(r)3 )
l
For 11–13-year-old females, the modeled requirement distribution is
FR (r) = Φ −1(–2.391755–3.901541log(r) + 3.938058log(r)2 --0.698517log(r)3 )
l
These approximations for the intake and requirement distributions are
very accurate when applied to values within the range of the reported per-
centiles. In the calculations used for the Target Median Intakes, the modeled
values given above are used for intakes between the 0.5 percentile and the
99.5 percentile (tabled values for intakes are given for the 1.0 percentile
and the 99 percentile) and for requirements between the 1.25 percentile
and the 98.75 percentile (tabled values for requirements are given for the
2.5 percentile and the 97.5 percentile). For values outside these ranges, the
cumulative distributions are set to zero for low values and one for high
values.
Using the Probability Approach and the Modeled
Distributions to Find Target Median Intakes
The probability approach was used with the modeled distributions to
determine the prevalence of iron inadequacy for 14–18-year-old females
and 11–13-year-old females. Alternative intake distributions were assumed
to be of the same distributional form but shifted to higher or lower values.
Computationally, this was accomplished by adding a constant to the value
of i in FI(i). The prevalence of inadequacy was computed for a range of val-
ues of the constant and the value corresponding to a 5 percent prevalence
of inadequacy was determined. The value represents the shift in the intake
distribution needed to achieve a 5 percent prevalence of inadequacy. The
Target Median Intake is the median of the shifted distribution.
For 14–18-year-old females, the Target Median Intake is 15.92 mg/d;
and 11–13-year-old females the Target Median Intake is 15.53 mg/d.