min C concentration of about 45 mg/L at 9 months (the midpoint of this age group) of lactation (Salmenpera, 1984) would be approximately 27 mg/day. Adding the intake from milk (27 mg/day) and food (22 mg/day), the total AI for vitamin C is rounded to 50 mg/day.

An alternative method to calculate vitamin C intake is to use the method described in Chapter 3 to extrapolate from the AI for infants ages 0 through 6 months who receive human milk. Utilizing this method, the AI for the older infants is rounded up to 50 mg/day of vitamin C. This is comparable to the value calculated above utilizing human milk and solid food.

The 1994 to 1996 CSFII data for infants 7 through 12 months of age ranged from 21 to 293 mg/day, with median 106 mg/day of vitamin C (Appendix Table D-1).

Vitamin C AI Summary, Ages 0 through 12 Months

AI for Infants

   

0–6 months

40 mg (227 µmol)/day of vitamin C

≈6 mg/kg

7–12 months

50 mg (256 µmol)/day of vitamin C

≈6 mg/kg

Children and Adolescents Ages 1 through 18 Years
Evidence Considered in Estimating the Average Requirement

No direct data were found on which to base an Estimated Average Requirement (EAR) for vitamin C for children ages 1 through 18 years. In the absence of additional information, and because vitamin C is a water-soluble vitamin and males have a larger lean body mass and total body water than women, EARs for children and adolescents have been estimated on the basis of relative body weight as described in Chapter 3 using reference weights from Chapter 1 (Table 1-1).

The Recommended Dietary Allowances (RDAs) estimated below for children 1 through 13 years of age are lower than the AIs calculated above for infants 0 through 12 months of age. The reason an AI may be higher than an RDA lies in the way they are determined (see “Differences Between the AI and the RDA” in Chapter 1). The AI is based on data on milk composition and volume of milk consumed to calculate an adequate intake of infants. The vitamin C RDA, in the case of 1- through 13-year-old children, is based on assumed differences in body weight from adults for whom there are some data. Thus, the data that are utilized to estimate the AI and RDA are different and cannot be compared.



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