Relation Dietary and Urinary Na, K, and Ca Level to Blood Pressure in Elderly People in Rural Area

Kwak, Eun Hee; Lee, Soo Lim; Lee, Hye Sang; Kwun, In Sook

Abstract

It has been considered that high Na intake, and low Ca/K intake are related to the incidence of hypertension. In this preliminary study, dietary Na, K, and Ca intake and their urinary excretion in rural area in Kyungpook province were measured to recognize the relationship between those blood pressure-related minerals and blood pressure regulation in elderly people in rural area of South Korea. Sixty eight subjects (male 39, female 29) aged over 60 were randomly selected in rural area in South Korea. Blood pressure and soup saltness were measured, and dietary intake using 24 hours recall and urinary excretion of Na, K and Ca were measured. Depending on the blood pressure level, the data were analyzed using non-parametric ANOVA of Kruskal Wallis analysis on the basis of categorizing of one of four blood pressure groups, such as normal, high normal, hypertension I and hypertension II. Mean systolic (124.2+/-15.1 mmHg) and diastolic (79.0+/-10.2 mmHg) blood pressures were within the normal range. Soup saltiness and systolic pressure was positively correlated (p<0.05). Even without statistical significance, dietary Na intake was higher in the upper systolic blood pressure groups then in the lower ones, which suggested higher Na intake caused the increase of blood pressure. No consistency was shown between the urinary concentration of Na, K, Ca level and blood pressure level, respectively. From the results of this study, it is assumed that high Na intake might be related to the incidence of hypertension. Further study with large sample size is needed to supplement the limitation of this preliminary study.