Potassium
Potassium
Also known as: Potassium chloride, Potassium citrate, Potassium bicarbonate, K+ (ionic form)
Potassium is an essential mineral and electrolyte critical for heart function, muscle contraction, nerve transmission, and blood pressure regulation. Most people do not consume adequate amounts.
Introduction
Potassium is an essential mineral and major cation (positive ion) in the body. Along with sodium and chloride, it is one of the primary electrolytes that maintain fluid balance, transmit nerve signals, and enable muscle contractions.
The body contains approximately 120 grams of potassium, with about 98% located inside cells. This intracellular concentration is maintained by the sodium-potassium pump (Na+/K+-ATPase), which uses about 20-30% of the body's resting energy expenditure.
Potassium's relationship with sodium is particularly important. While sodium tends to increase blood pressure, potassium helps lower it by promoting sodium excretion through the kidneys, relaxing blood vessel walls, and reducing the effects of angiotensin II.
Despite its importance, most people in developed countries consume inadequate potassium. The average intake in the US is only about 2,500 mg/day, well below the recommended 3,400-4,700 mg. This is largely due to low consumption of fruits and vegetables and high consumption of processed foods.
Increasing potassium intake through diet (fruits, vegetables, legumes) is associated with reduced blood pressure, lower stroke risk, and reduced risk of kidney stones and osteoporosis. Supplementation should be approached cautiously, especially in those with kidney disease or taking certain medications.
Main Benefits
Lowers blood pressure by promoting sodium excretion, relaxing blood vessels, and counteracting effects of high sodium intake.
Reduces risk of stroke and cardiovascular disease; higher intake associated with lower stroke incidence.
Essential for normal heart rhythm; deficiency causes dangerous arrhythmias and cardiac arrest.
May reduce kidney stone risk by increasing urinary citrate and reducing calcium excretion.
Supports bone health by reducing calcium loss and may help preserve bone mineral density.
Mechanism of Action
Potassium functions through multiple mechanisms:
Blood Pressure Regulation: Potassium lowers blood pressure through several mechanisms:
- Promotes sodium excretion through kidneys (natriuresis)
- Relaxes vascular smooth muscle, reducing peripheral resistance
- Reduces sensitivity to angiotensin II
- Modulates baroreceptor sensitivity
Electrolyte Balance: As the primary intracellular cation, potassium maintains:
- Cell membrane potential (essential for all cells)
- Fluid balance between intracellular and extracellular compartments
- Acid-base balance
Nerve Transmission: The sodium-potassium pump maintains the electrochemical gradient across nerve cell membranes. Action potentials (nerve impulses) depend on rapid sodium influx and potassium efflux.
Muscle Contraction: Muscle cells require proper potassium concentrations for:
- Action potential generation in muscle fibers
- Coupling of electrical signals to muscle contraction
- Normal heart muscle function
Kidney Stone Prevention: Potassium citrate increases urinary pH and citrate, which inhibits calcium oxalate and uric acid stone formation.
Bone Health: Potassium's alkalizing effect reduces bone resorption and calcium loss, potentially preserving bone mineral density.
Natural Sources
Potassium is abundant in fruits, vegetables, legumes, and dairy. Processed foods are typically low in potassium and high in sodium.
Examples:
White beans and lentils
Potatoes (with skin)
Sweet potatoes
Beet greens and spinach
Avocado
Bananas
Yogurt
Salmon and halibut
Coconut water
Oranges and orange juice
Abundant in whole foods; deficiency rare with adequate diet; most people consume less than recommended; processed foods low in potassium.
Deficiency Symptoms
Hypokalemia (low blood potassium) causes weakness, arrhythmias, and can be life-threatening. Usually results from losses (diuretics, vomiting, diarrhea) rather than inadequate intake alone.
Common Symptoms:
Muscle weakness and cramps
Fatigue
Constipation
Heart palpitations and arrhythmias
Tingling and numbness
Breathing difficulties (severe deficiency)
Life-threatening cardiac arrest (severe deficiency)
Dietary deficiency uncommon; hypokalemia usually from medical conditions or medications (diuretics, laxatives); most people get some potassium but below optimal amounts.
Can cause life-threatening cardiac arrhythmias; muscle paralysis possible; serious medical emergency when severe.
Recommended Daily Intake
AI: 3,400 mg/day for men, 2,600 mg/day for women. No established UL for dietary potassium; supplements limited to 99 mg per serving in US due to toxicity risk.
Reference Values:
| Adult men | 3,400 mg/day (AI) |
| Adult women | 2,600 mg/day (AI) |
| Pregnancy | 2,900 mg/day (AI) |
| Lactation | 2,800 mg/day (AI) |
| Supplement limit | 99 mg per serving (US) |
Sources for RDI/AI:
Most potassium should come from food. US regulations limit potassium supplements to 99 mg per serving due to hyperkalemia risk. Salt substitutes provide potassium chloride.
Effectiveness for Specific Focuses
Strong evidence for blood pressure reduction and stroke prevention; essential for heart rhythm; foundational for cardiovascular health.
Potent blood pressure lowering effect; increases sodium excretion; relaxes blood vessels; DASH diet cornerstone; prevents stroke.
Essential for muscle function; lost in sweat; important for preventing cramps; critical for hydration balance.
May preserve bone mineral density; reduces calcium loss; modest effect on bone health.
Safety Information
Potential Side Effects
Gastrointestinal upset (supplements)
Hyperkalemia (high blood potassium) - dangerous
Heart arrhythmias (with excess)
Muscle weakness (with excess)
Contraindications
Kidney disease (reduced potassium excretion)
ACE inhibitors and ARBs
Potassium-sparing diuretics
Severe dehydration
Overdose Information
No UL for dietary potassium, but supplements can cause hyperkalemia; life-threatening cardiac arrhythmias possible; FDA limits supplements to 99 mg.
Hyperkalemia causes muscle weakness, paralysis, heart arrhythmias, cardiac arrest. Potentially fatal.
Documented Overdose Symptoms:
Muscle weakness
Heart arrhythmias
Cardiac arrest
Paralysis
Dietary potassium very safe. Supplemental potassium can be dangerous, especially with kidney impairment or ACE inhibitors/ARBs.
Interactions
Drug Interactions:
ACE inhibitors and ARBs (increase potassium retention)
Potassium-sparing diuretics (amiloride, spironolactone, eplerenone)
NSAIDs (may increase potassium)
Heparin (increases potassium)
Dangerous hyperkalemia risk with ACE inhibitors, ARBs, and potassium-sparing diuretics; medical supervision required.
Other Supplement Interactions:
Salt substitutes (often potassium chloride) - additive effects
Calcium - may compete for absorption
Salt substitutes add significant potassium; caution with multiple potassium sources.
Do NOT use potassium supplements without medical supervision if taking ACE inhibitors, ARBs, or potassium-sparing diuretics, or if you have kidney disease. Hyperkalemia can be fatal.
Forms and Bioavailability
Potassium supplements in the US are limited to 99 mg per serving. Potassium chloride is most common; citrate may have additional benefits for kidney stones.
Potassium Chloride
Most common form; well-absorbed; also used in salt substitutes.
Good bioavailability; inexpensive; well-studied; effective.
Standard form. Can irritate stomach; take with food. Used in salt substitutes (Nu-Salt, NoSalt).
Potassium Citrate
Alkalizing form; well-absorbed; provides citrate which inhibits kidney stones.
Good absorption; citrate component beneficial for urinary pH and stone prevention.
Preferred form for kidney stone prevention. Less stomach irritation than chloride form. May have better cardiovascular effects.
Potassium Bicarbonate
Alkalizing form; may help neutralize dietary acid load.
Good absorption; alkalizing effect may benefit bone health and blood pressure.
Used in some research studies showing cardiovascular and bone benefits. Less commonly available as supplement.
Warnings & Suitability
Did You Know...?
The sodium-potassium pump (Na+/K+-ATPase) uses about 20-30% of the body's resting energy expenditure - more than any other cellular process.
Bananas are famous for potassium, but a medium potato with skin actually contains more than twice as much potassium (about 900 mg vs 400 mg).
The "lethal injection" used in capital punishment in the US typically includes potassium chloride to stop the heart.
Salt substitutes like Nu-Salt and NoSalt are almost pure potassium chloride and can provide substantial potassium intake for those limiting sodium.
General Scientific Sources
Tags
Content Verification
Last Medical Review: 2/13/2026
Reviewed by: Editorial Team