When people ate more potassium, their blood pressure went down a little—but the amount it dropped varied a lot depending on which study you looked at, so we’re not sure exactly how much potassium helps lower blood pressure.

Scientists tried to figure out how much of the blood pressure drop in a big study was due to eating less salt versus eating more potassium — and they found it’s hard to say exactly how much each one helped, because the numbers varied a lot depending on how they did the math.

When people used a special salt substitute with less sodium and more potassium, their blood pressure dropped more than scientists expected just from lowering salt — suggesting the extra potassium might be helping out in a way that’s more than just adding two effects together.

If you eat more potassium-rich foods and less salty food, your blood pressure might drop by about 3.3 mmHg—and most of that drop probably comes from eating more potassium, not less salt.

Eating the right amount of potassium—between 90 and 120 millimoles a day—seems to lower your blood pressure the most and cut your risk of stroke the most; eating more than that doesn’t help any further.

If you eat more potassium-rich foods and less salty food, your blood pressure might drop by a few points—and most of that drop probably comes from eating more potassium, not less salt.