first approximation of the requirement for this age group. A number of assumptions related to serum Pi during adolescence and growth needs were necessary to complete this calculation, and the resulting value was not dissimilar from that determined using tissue accretion and the factorial method.

EAR Summary: Ages 9 through 13 and 14 through 18 Years

The EAR for children ages 9 through 13 years can be set based on the factorial approach at 1,055 mg (34 mmol)/day. Although accretion data are not available for ages 14 through 18 years, it seems reasonable to maintain this EAR value for the older adolescent since a similar value was obtained using the serum phosphorus curve extrapolated from adults. It should be noted, however, that this age range (9 through 18 years) brackets a period of intense growth, with growth rate, absorption efficiency, and normal values for ECF Pi changing during this time. Because of the similarity of these sexspecific estimates and the uncertainties involved, a single value of 1,055 mg (34 mmol)/day is selected for both males and females ages 9 through 18 years.

EAR for Boys

9 through 13 years

1,055 mg (34 mmol)/day

 

14 through 18 years

1,055 mg (34 mmol)/day

EAR for Girls

9 through 13 years

1,055 mg (34 mmol)/day

 

14 through 18 years

1,055 mg (34 mmol)/day

Utilizing the 1994 CSFII intake data, adjusted for day-to-day variations (Nusser et al., 1996), this EAR of 1,055 mg (34 mmol)/day is slightly below the twenty-fifth percentile (1,090 mg [35.2 mmol]) of phosphorus intake for boys, aged 9 through 13 years, and slightly above the twenty-fifth percentile of intake (1,005 mg [32.4 mmol]) for girls in this same age range (see Appendix D). For boys ages 14 through 18, the EAR of 1,055 mg (34 mmol)/day is close to the tenth percentile (1,072 mg [34.6 mmol] ) of phosphorus intake. The EAR of 1,054 mg (34 mmol)/day for girls ages 14 through 18 is slightly below the fiftieth percentile (1,097 mg [35.4 mmol]) of phosphorus intake.

Determination of the RDA: Ages 9 through 13 and 14 through 18 Years

The variance in requirements cannot be determined from the available data. Thus, a CV of 10 percent (1 SD) is assumed. This results in a RDA for phosphorus of 1,250 mg (40.3 mmol)/day for girls and boys ages 9 through 18 years.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement