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.