Studies in community nutrition: Estimation of sodium output

A practical procedure for estimating dietary intake of salt would facilitate examination of the possible relationship between salt intake and hypertension and could provide feedback to aid persons in changing salt intake when such is recommended. This is a study with 19 subjects of a sampling procedure of estimating sodium output which requires less patient cooperation than that needed for a 24-hr urine sample. Each subject provided timed urine samples for portions of the entire 24-hr period for three consecutive days. Sodium excretion for any one of the entire 24-hr periods correlated well with the mean 24-hr excretion for the 3-day period. The mean sodium excretion of the three 9-hr overnight urine samples correlated equally well with the mean 24-hr excretion for the entire 3-day period. This latter procedure, which puts far less a burden of compliance on the subjects, is suggested as preferable to obtaining a 24-hr urine sample. For purposes of checking compliance with dietary suggestions, it is possible to replace the analysis for sodium with a simple titrator strip that measures chloride.