provides support for combining the ages of 4 through 8 years in terms of phosphorus needs. The overall mean value for males of 62 mg (2.0 mmol)/day phosphorus accrued is in the same range as the value 68.2 mg (2.2 mmol)/day computed from the phosphorus composition of weight gain from Sheikh et al. as cited in the review by Lemann (1996). The slightly lower value of 40.8 mg (1.3 mmol)/day for females presumably reflects the differences in the amount of bone and lean tissue between the sexes at this age interval.

The value derived for phosphorus accretion of lean and osseous tissue is supported by estimates of phosphorus retention from balance studies in children aged 4 to 12 years; that is, phosphorus retention of 10 g (323 mmol)/kg body weight gained (Fomon et al., 1982), when applied to the average weight gain over this age interval. For males, ~2.15 kg are gained each year over this period (Fomon et al., 1982); thus a total increment of 21.6 g (697 mmol) of phosphorus is gained each year. Daily accretion of phosphorus is then predicted to be 60 mg (1.9 mmol). For females, daily phosphorus accretion calculated in this manner would be 62 mg (2.0 mmol). These estimates are similar to those calculated by summing phosphorus accretion in lean and bony compartments (Table 5-4).

For the factorial estimate of the EAR for children ages 4 through 8 years, as outlined previously for children ages 1 through 3 years, and an accretion value of 62 mg (2.0 mmol)/day, a value of 405 mg (13.1 mmol)/day was derived. The assumptions for efficiency of phosphorus absorption and urinary loss of phosphorus are identical to that used for the 1 through 3 years age group.

The estimated EAR for boys and girls ages 4 through 8 years is 405 mg (13.1 mmol)/day.

Utilizing the 1994 CSFII intake data, adjusted for day-to-day variations (Nusser et al., 1996), this value derived for the EAR again represents a low dietary intake of phosphorus, as it falls below the first percentile of intake, 537 mg (17.3 mmol)/day, for phosphorus intakes of children aged 4 through 8 years (see Appendix D). Since excess phosphorus intake will be excreted, consuming intakes in excess of physiological needs by such a magnitude is not likely of any consequence.