Abstract
Excessive salt intake is blamed for high frequency of hypertension in Japan. Japanese dietary habit is recently changing with expectation of less consumption of salt.
We picked up ten sanatorium scattering all over Japan and investigated exact daily salt intake among their in-patients on regular diet. Each of ten facilities chose volunteers of in-patients who agree to join this study and were instructed to eat all of their meal and on more than that. 24-hours urine were collected daily for 3 days to determine the amount of excreted sodium and creatinine per day. Urine sample with less than one gram creatinine were excluded as incomplete collection of 24-hours urine.
The average daily salt excretion among all ten facilities was 10.81±3.51g/day. This value was less than average Japanese salt intake and was very close to the guide line figure 10g/day by Ministry of Health and Welfare. However, there was wide distribution among facilities, ranging from 7.08±0.54g/day to 12.72±2.54g/day with ratio of 1 to 1.8.
Sodium excretion of three consecutive days were compared each other. Day 1 to Day 2, Day 1 to Day 3, and Day 2 to Day 3 were all well correlated respectively. So, single 24-hours urine sample could be enough to determine daily sodium excretion.
