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large (likely attributable to methodological limitations) to use these data with any confidence in setting an EAR. However, these data are consistent with the EAR derived from a factorial approach.

Zinc EAR and RDA Summary, Ages 4 through 8 Years

EAR for Children

4–8 years

4 mg/day of zinc

The RDA for zinc is set by using a CV of 10 percent (see Chapter 1) because information is not available on the standard deviation of the requirement. The RDA is defined as equal to the EAR plus twice the CV to cover the needs of 97 to 98 percent of the individuals in the group (therefore, the zinc RDA is 120 percent of the EAR). The calculated RDA was rounded to the nearest 1 mg.

RDA for Children

4–8 years

5 mg/day of zinc

Children Ages 9 through 13 Years

Evidence Considered in Estimating the Average Requirement

Factorial Analysis. Estimates used for factorial analysis are similar for boys and girls, and therefore calculations are used to estimate a single average requirement for both genders. With use of the same values as for younger children, an average accretion of 10 g/day of new tissue (Kuczmarski et al., 2000), and a reference weight of 40 kg, the required amount of absorbed zinc is 2.1 mg/day (Table 12-5). Based on a fractional absorption of 0.3 observed in infants and young children (Davidsson et al., 1996; Fairweather-Tait et al., 1995), the EAR is 7 mg/day.

TABLE 12-5 Requirement for Absorbed Zinc for Children Aged 9 through 13 Years

Intestinal losses

34 μg/kg/day × 40 kg

= 1,360 μg/day

Urinary and integumental losses

14 μg/kg/day × 40 kg

= 560 μg/day

Requirement for growth

10 g/day × 20 μg/g

= 200 μg/day

Required absorbed zinc

 

= 2,120 μg/day



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