not yet into maximal growth at this age, appear to require about the same amount of magnesium as girls per kg per day. Thus, the EAR is estimated to be 5 mg (0.21 mmol)/kg/day for boys ages 9 through 13 years. Based on a reference weight of 40 kg (Table 1-3) for boys ages 9 through 13 years, their EAR is 200 mg (8.3 mmol)/day.

EAR for Boys

9 through 13 years

200 mg (8.3 mmol)/day

Based on the 1994 CSFII magnesium intake data adjusted for day-to-day variation (Nusser et al., 1996), the tenth percentile of intake for boys ages 9 through 13 years is 181 mg (7.5 mmol)/day, and the twenty-fifth percentile intake is 216 mg (9 mmol)/day (see Appendix D). Thus the EAR of 200 mg (8.3 mmol)/day for boys ages 9 through 13 years would fall between the tenth and twenty-fifth percentile of intake in this age category.

EAR Summary: Ages 9 through 13 Years, Girls

Because the protein intake of the younger girls in the Andon et al. (1996) study was not indicated, it is possible that one of the reasons that most of the girls were in positive magnesium balance on the 176 mg (7.3 mmol)/day intake was their higher intake of dietary protein. The second possible reason is their younger age and body size. In the absence of additional data and assuming a protein intake of 50 g/day, the EAR for girls ages 9 through 13 years is 5 mg (0.21 mmol)/kg/day, based primarily on the Andon et al. (1996) study, in which all girls who consumed this level or less were in positive balance. Their average weights were 41 kg (90 lb), and few had yet started menarche. In the Greger et al. study (1979), the average weight was 52.5 kg (115.7 lb), and 6 of the 11 girls had already started menarche. Their requirements reflect a greater lean body mass. Thus, based on the reference weight of 40 kg (Table 1-3) for girls ages 9 through 13 years, their EAR is 200 mg (8.3 mmol)/day.

EAR for Girls

9 through 13 years

200 mg (8.3 mmol)/day

Based on the 1994 CSFII intake data and adjusted for day-to-day variation (Nusser et al., 1996), the twenty-fifth percentile magnesium intake for girls ages 9 through 13 years is 194 mg (8.1 mmol), and the median intake is 224 mg (9.3 mmol)/day (see Appendix D). Thus, the magnesium EAR of 200 mg (8.1 mmol)/day would be



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