What it is
Potassium is the inside-the-cell partner to sodium's outside: together they run fluid balance, nerve signals, and muscle contractions — your heartbeat included. The sodium-potassium ratio matters to blood pressure as much as sodium alone, and modern diets get it backwards on both ends.
How much
Adequate intakes run around 2600–3400 mg a day — a bar most people miss by a wide margin, since potassium lives in exactly the whole foods modern eating skimps on. It's a floor to work toward, not a ceiling. The exception that matters: anyone with kidney disease or on potassium-affecting medication should follow their clinician's numbers, where too much becomes the concern.
How well it's tracked
Moderately: potassium joined newer labels and is well covered for produce in generic data, but plenty of older label entries omit it — expect a mild undercount.
Food sources
The banana is famous; the potato is better — and beans, lentils, dairy, salmon, avocado, squash, and leafy greens all outperform their reputation. Eating potassium well and eating "more whole foods" are nearly the same instruction.
In the app
Potassium's Insights card with contributors shows which foods do your heavy lifting, and its goal works as a floor — the direction that actually needs the push.