Potassium
The mineral most Americans dramatically under-consume. Critical for blood pressure, muscle function, and electrolyte balance. Food-first; supplements are dose-capped for safety reasons.
Strong evidence that adequate potassium intake reduces blood pressure, stroke risk, and cardiovascular mortality. The DASH diet (high in fruits and vegetables, hence high in potassium) lowers BP comparably to a single antihypertensive medication. Effects: 2–4 weeks for BP.
Potassium is the primary intracellular cation — the partner to sodium that drives nerve impulses, muscle contraction, and the maintenance of cellular electrical gradients. Adequate intake lowers blood pressure (works by relaxing vascular smooth muscle and offsetting sodium's effects), reduces stroke risk, supports bone density, and prevents muscle cramps. The RDA is 3,500–4,700 mg/day; most Americans get half that. The catch: supplemental potassium is FDA-capped at 99 mg per pill (low-acid concentrations of potassium can ulcerate the GI tract; bulk dosing can dangerously elevate blood potassium and stop the heart). So getting enough is almost entirely a food problem.
- Form
- Food first (food potassium is delivered slowly and safely). Supplemental: potassium citrate, gluconate, or chloride — capped at 99 mg per OTC pill in the US. Lite-Salt (50/50 sodium / potassium chloride) is the easiest practical supplement. Prescription potassium chloride is available for documented deficiency.
- Dose
- Total intake: 3,500–4,700 mg/day. OTC supplements rarely deliver meaningful amounts on their own — they're top-ups, not solutions.
- Timing
- With food. Spread doses across the day if supplementing.
- Schedule
- Daily (food primarily).
- Side effects
- GI upset, ulcer risk from concentrated pill forms. Cardiac arrhythmias and arrest from too-rapid IV or oral mega-doses.
- Interactions
- ACE inhibitors, ARBs, potassium-sparing diuretics (spironolactone, eplerenone) — all raise potassium; supplementing on top can cause dangerous hyperkalemia. NSAIDs mildly elevate potassium. Digoxin — potassium balance critical for safety.
- Contraindications
- Kidney disease (CKD stage 3+) — kidneys clear potassium; impaired kidneys can't, supplementation is dangerous. On any of the K-elevating medications above — supplement only under medical supervision with blood monitoring. Addison's disease.
- Lab markers
- Serum potassium (normal 3.5–5.0 mEq/L). Narrow safe range — both high and low are dangerous. Pair with serum sodium and creatinine for context.
- Food sources
- Beans (especially white and black beans), potato (especially with skin), sweet potato, spinach, swiss chard, beet greens, avocado, banana, salmon, yogurt, coconut water, oranges, dried apricots, tomato paste. One banana ≈ 400 mg — not as much as the reputation suggests.
Pairs with
Magnesium — these track together; magnesium deficiency makes potassium repletion harder. Sodium (paradoxically — getting the ratio right matters more than absolute amounts; aim for higher K than Na).
within Minerals