Several trials have documented that reduced sodium intake lowers blood pressure in older adults (Alam and Johnson, 1999; Appel et al., 2001; Cappuccio et al., 1997; Cobiac et al., 1992; Johnson et al., 2001; Weinberger and Finberg, 1991; Weinberger et al., 1986). Some trials have directly evaluated the effect of age on blood pressure responses to dietary sodium reduction. Greater reduction in blood pressure in response to reducing dietary sodium levels to less than 1.75 g (75 mmol)/day in adults over 40 years of age (up to age 54) compared with younger adults aged 21 to 39 years has been reported (Miller et al., 1987). Significantly greater systolic blood pressure reduction from a lower (versus higher) sodium intake in persons older than 45 years compared with those 45 years of age or younger has also been noted (Vollmer et al., 2001).

Limited evidence suggests that sodium sweat concentrations in the elderly are not different from those of young adults (Inoue et al., 1999) (see Table 6-3).

Overall, the data cited above provide no firm basis to modify the AI for older persons. Thus the AI for older adults is extrapolated from younger adults based on the combined average for men and women of median energy intakes (which do decrease with age). Median energy intakes for older women based on the CSFII were 1,507 and 1,356 kcal for 51 through 70 years and 71 years and older, respectively; for older men, median energy intakes were 2,109 and 1,773 kcal/day for 51 through 70 years and 71 years of age and older, respectively (IOM, 2002). The median energy intakes for both genders were averaged.

In summary, extrapolating from younger individuals based on energy intake, the AI is 1.3 g (55 mmol)/day for men and women 51 to 70 years and 1.2 g (50 mmol)/day for those 71 years and older. Chloride is calculated on an equimolar basis: the AI for those 51 through 70 is 2.0 g (55 mmol)/day; for those 71 years of age and older, 1.8 g (50 mmol)/day.