Abstract
Sodium and potassium intake through successive three-day habitual diets of 20 individuals aged. from 16 to 86 years and their 24 hours urinary excretion of sodium and potassium on the three identical days were determined directly by the absorption spectrophotometer. During the same period the blood pressure, was checked at the hospital. The data were analyzed according to the following three age groups; 16 to 29 years (Y group), 33 to 53 years (M group), and 62 to 86 years (O group). The food and urine samples were kept freezed until determination of sodium and potassium. Total sodium intake in mg/day ranged from 6, 019 to 9, 137, the highest being in Y group. Urinary sodium excretion corresponding to 89.7% of sodium intake in the average without age differences, ranging from 5, 452 to 8, 968 mg/day. Correlation between intake and excretion of sodium was highly significant (p<0.001). Total potassium intake in mg/day ranged from 1, 757 to 2, 878, the highest being in O group. Urinary potassium excretion was 82.0% of the intake in the average, declining from Y group to O group like 89.5, 83.1 and 61.6. The sodium: potassium ratio in food fell with the age; Y group 3.6, M group 3.2, and O group 2.4, but that of urine did not indicate any definite age group difference with the values of around 3.5.
