1. n=26 boys aged 14–19 y and 37 girls aged 13–17 y; all healthy volunteers (Eissenstat et al., 1986)

2. n=8 boys and 4 girls; aged 11–16 y (Kathman and Kies, 1984)

Usual intake was based on 4 studies:

1. n=23 (16 females, 7 males), aged 18–53 y (mean 26 y), 19 Caucasian, 4 Chinese, all normal healthy volunteers (Kathman and Kies, 1984)

2. n=7,277 randomly selected British households from the U.K. National Food Survey (Bull and Buss, 1982)

3. n=37 males, 54 females (26 institutionalized, 65 noninstitutionalized), aged 65+ y (Srinivasan et al., 1981)

4. n=12 healthy men, half were aged 21–35 y and half were aged 65–79 y (Tarr et al., 1981)