How does sodium and potassium intake affect blood pressure?

This study evaluated how sodium and potassium intake and their ratio affect blood pressure, by comparing hypertensive (patients with high blood pressure or hypertension) with non-hypertensive individuals. 

Sodium and potassium are essential chemical elements found in our body and are consumed in our daily diet (for example sodium in salt and potassium in bananas). The recommended consumption amount should be 3,000 mg daily for sodium and 4,700 mg daily for potassium, and the sodium-to potassium ratio should be lower than 1. In addition, sodium and potassium also have an important role in regulation of blood volume, blood pressure, blood acidity level (pH) and kidney function. Altered sodium and potassium balance can cause hypertension (blood pressure levels higher than 140/90 mmHg), which is considered to be a major risk factor for heart disease. Hypertension can be prevented or reversed by diet and physical activity.

10,563 individuals were chosen for this trial. Participants were not under a specific diet and were not taking any blood pressure lowering medications. Sodium and potassium were measured according to food consumption and blood pressure was measured in a single physical examination. The results showed that systolic blood pressure (the pressure in the arteries when the heart beats, normally between 90 and 120 mmHg) was increased by 1.04 mmHg per 1000 mg/d sodium intake, while it decreased by 1.24 mmHg per 1000 mg/d potassium intake. It was found that hypertensive individuals generally had higher sodium and lower potassium intake compare to non-hypertensive individuals. 

In conclusion, this article found that there was an association between increased sodium intake and high blood pressure, indicating that a change in diet to low sodium and high potassium can help maintain blood pressure within the normal range.

The evaluation of sodium and potassium intake was based on a dietary recall interview and not on blood test. This could have under- or overestimated the actual results. 

Ask your doctor about changing your diet according to the recommended sodium and potassium amounts and regularly check your blood pressure.