How dietary potassium lowers blood pressure
Potassium helps the kidneys excrete sodium and relaxes blood vessel walls, both of which tend to lower blood pressure. Pooled trial data suggest that increasing potassium intake produces a small but real reduction in systolic pressure, on the order of a few mmHg, with a larger effect in people who are hypertensive or eating high-sodium diets. The relationship across the typical intake range is broadly graded.
The effect partly reflects the balance between sodium and potassium rather than potassium alone, which is why both are usually considered together.
Getting potassium safely from food first
Most guidance favors raising potassium through food (fruits, vegetables, legumes, dairy) rather than supplements, because food sources are not associated with the buildup risk that concentrated supplements can pose. Potassium supplements and salt substitutes can be hazardous for people with reduced kidney function or those on certain blood pressure medications.
This is general educational information, not medical advice. Anyone with kidney disease or on medication affecting potassium should consult a clinician before increasing intake.