Why the ratio shifted from ancestral diets
Diets based on minimally processed plants and fresh foods tend to deliver more potassium than sodium, the pattern thought to characterise ancestral eating. Modern processed and restaurant foods add large amounts of sodium while displacing potassium-rich produce, inverting the balance so that many Western diets supply substantially more sodium than potassium.
Researchers increasingly look at the sodium-to-potassium ratio rather than sodium alone, because the two minerals have opposing effects on fluid balance and vascular tone, and intake of one influences the impact of the other.
How sodium and potassium affect blood pressure
Higher sodium intake tends to raise blood pressure in many people, while higher potassium intake tends to counter that effect, partly by promoting sodium excretion and relaxing blood vessel walls. A diet higher in potassium and lower in sodium is associated with lower average blood pressure across populations.
Responses vary between individuals, and potassium intake must be approached carefully by people with kidney disease or those on certain medications, for whom extra potassium can be dangerous. This is general educational information, not medical advice; consult a qualified professional before changing sodium or potassium intake for a health condition.