Objective: The aim of the study was to examine the adherence to a salt restriction diet and the effect of salt restriction on blood pressure in free living subjects with mildly elevated blood pressure.
Design: Subjects with mildly elevated blood pressure participated in a controlled study on the effect of salt restriction on blood pressure. Subjects received oral and written instructions by a clinical nutritionist to reduce sodium chloride intake to five grams per day. A low sodium bread (0.5%) was supplied free of charge for the subjects during the whole low-sodium period (between weeks 4-24).
Subjects and methods: Subjects were recruited from previous studies at the Kuopio Research Institute of Exercise Medicine and from local occupational health care services. Twenty-four men and 15 women aged 28-65 y with the mean daytime ambulatory diastolic blood pressure between 90-105 mmHg and office diastolic blood pressure between 95-115 mmHg were included in the study. Salt intake was monitored by 4-d food diaries and 24-h urinary sodium excretion.
Results: Twenty percent of the subjects achieved a urinary sodium excretion level of less than 74 mmol/24 h corresponding to a salt intake of five grams per day. There was a significant decline (7.1+/-12.7/4.2+/-7.5) in systolic and diastolic blood pressure levels during the salt restriction diet.
Conclusions: Even moderate salt restriction seems to be effective in the treatment of mildly elevated blood pressure. However, the recommended salt intake level of less than five grams per day is difficult to achieve even after intensive counselling and regular use of low salt bread.