mean arterial blood pressure was seen (Miller and Weinberger, 1986; Miller et al., 1988). In another trial of 80 hypertensive children (6 to 9 years old) with sodium intakes of 2.0 g (87 mmol)/day versus 2.9 g (130 mmol)/day, there were no significant reductions in blood pressure (Gillum et al., 1981), possibly because of the limited contrast in sodium intake.

In a controlled trial of adolescents, a 3-year reduced sodium intervention lowered the age-related increase in systolic and diastolic blood pressure in girls, but not in boys (Sinaiko et al., 1993). As in other trials, the contrast in urinary sodium excretion was small.

Overall, available evidence on the effects of sodium reduction on blood pressure in children is limited and inconsistent. Hence there are insufficient data to directly set a UL based on expected blood pressure change. Therefore, the ULs for children and adolescents were determined by extrapolating from the adult ULs based on averages of median energy intakes as was used for setting the AIs for children.

Extrapolation of the adult UL to children is appropriate. Numerous observational studies have documented that blood pressure tracks with age from childhood into the adult years (Bao et al., 1995; Dekkers et al., 2002; Gillman et al., 1993; Van Lenthe et al., 1994). Further, it is increasingly recognized that the antecedents of chronic conditions in adults, such as elevated blood pressure and atherosclerosis, occur in childhood.

The median energy intake for adults was 2,150 kcal/day. For children 1–3, 4–8, and 9–13 years of age, the median energy intakes were 1,372, 1,757, and 2,042 kcal/day, respectively. The ULs for children are extrapolated from the adult UL of 2.3g (100 mmol)/day based on these estimated energy intakes, after rounding. Since the estimated energy intake for adolescents is in the same range as adults, the ULs for this age group are the same as those for adults.