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weighing 70 kg would require—a higher percentage than that represented by actual weight.

  1. The EAR for adults is an estimate of maintenance needs.

  2. The percentage of extra B vitamins and choline needed for growth is comparable with the percentage of extra protein needed for growth.

  3. On average, total needs do not differ substantially for males and females until age 14, when reference weights differ.

The formula for the extrapolation is

EARchild = EARadult (F),

where F = (Weightchild/Weightadult)0.75 (1 + growth factor). Reference weights from Table 1-2 are used. If the EAR differs for men and women, the reference weight used for adults differs by gender; otherwise, the average for men and women is used unless the value for women is derived from data on men. The approximate proportional increase in protein requirements for growth (FAO/WHO/ UNA, 1985) is used as an estimate of the growth factor as shown in Table 2-1. If only an AI has been set for adults, it is substituted for the EAR in the above formula and an AI is calculated; no RDA will be set.

Setting the RDA

To account for variability in requirements because of growth rates and other factors, a 10 percent coefficient of variation (CV) for the

TABLE 2-1 Growth Factors Used to Extrapolate DRIs

Age Group

Growth Factor

7 mo–3 y


4–8 y


9–13 y


14–18 y, Males


14–18 y, Females


NOTE: Growth beyond age 13 for females is assumed to represent a negligible increased requirement for vitamins.

SOURCE: The proportional increase in protein requirements for growth from FAO/ WHO/UNA (1985) was used to estimate the growth factor indicated.

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