Dietary electrolyte intake and blood pressure in older subjects: The Rotterdam Study

Objective. To examine the relation between dietary electrolyte intake and blood pressure in older people. Methods. The study included 3239 participants of the Rotterdam Study (41% of the total cohort) who were aged over 55 years and had not been prescribed antihypertensive drugs. Their dietary intake was assessed by a semiquantitative food frequency questionnaire. The association of energy-adjusted intakes of potassium, magnesium and calcium with blood pressure was studied in a linear regression model with adjustment for age, sex, body mass index and alcohol intake. Results. An increase in potassium intake of 1 g/day was associated with a 0.9 mmHg lower systolic and a 0.8 mmHg lower diastolic blood pressure. An increase in magnesium intake of 100 mg was associated with a 1.2 mmHg lower systolic and a 1.1 mmHg lower diastolic blood pressure. Calcium intake was not independently related to blood pressure, except for a subgroup of 1360 hypertensive subjects in which a significant inverse association with diastolic blood pressure was observed. Conclusions. Our findings support the view that an increase in the intake of foods rich in potassium and magnesium could lower blood pressure at older age.