Relationship between dietary cations and blood pressure.

The relationship between dietary cations and blood pressure is complex. Epidemiological evidence points to a significant independent positive relationship between dietary sodium and blood pressure. The same evidence favours the existence of a significant negative relationship between dietary potassium and blood pressure. On a molar basis 1 mmol of potassium is about 2.5 times more effective in lowering blood pressure than sodium is in raising it. The evidence concerning the effect of dietary calcium on blood pressure remains controversial. Intervention studies favour a blood-pressure-lowering effect, but serum and urinary calcium correlate positively with blood pressure. Dietary magnesium has probably a slight blood-pressure-lowering effect, but more data are needed in order to evaluate its importance. At the population level blood pressure is significantly related to the dietary intake of cations.