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Potassium is essential for normal bodily function. It is obtained in the diet and found in several foods. Potassium-containing drugs are sometimes used to treat certain conditions. Potassium salts (e.g. potassium chloride) are used in reduced-sodium added-potassium salt substitute interventions and in sodium restriction diets to help treat high blood pressure.
Potassium is most often used for
Last Updated:March 14, 2024
Potassium, an element essential for maintaining normal cellular function in the body, regulates electrolyte balance, blood pressure, and electrical impulses in nerves and muscle cells.[5][6] The latter is crucial for maintaining contractile function in muscles, including the heart.
Potassium is obtained in the diet and is found in many foods, including fruits, vegetables, legumes, meat, and animal products (milk, yogurt, etc.).[1][3] In the USA, the adequate intake (AI) for potassium — the amount assumed to ensure nutritional adequacy — in adults without known health conditions is 3,400 mg/day in males and 2,600 mg/day in females, but the AI changes with age and during pregnancy (see the Dosage Information section).[1][3]
The potassium concentration in the blood is tightly regulated within a range of 3.5 to 4.5 millimoles per liter of blood (mmol/L).[5][7][6] Several factors can push blood potassium concentrations outside this range. These include dietary potassium intake, some drugs (e.g., insulin, diuretics, and potassium binders), and certain clinical conditions (e.g., chronic kidney disease and diabetic ketoacidosis).[5][7][6][8][9] Blood potassium concentrations outside the healthy reference range — hyperkalemia (high blood potassium[10]) and hypokalemia (low blood potassium[11]) — are problematic because they’re associated with an increased risk of heart problems (e.g., heart arrhythmias) or dying from a cardiovascular event.[12][13][14][15][16][17]
Some studies have shown that short-term daily supplementation with a potassium salt (e.g., potassium chloride or potassium citrate) can lower blood pressure in adults without known health conditions[18] and in people with hypertension.[19][20] While early systematic reviews and meta-analyses found that the evidence was mixed and that there was large variability in effects between studies,[21] it now appears that supplementation with a potassium salt can cause a moderate and meaningful effect to lower blood pressure.[22][23] However, the blood-pressure-lowering effect of potassium is likely to be greatest in people with lower potassium intake at baseline, higher sodium intake at baseline, or in people who don’t use a blood-pressure-lowering medication.[23][24]
Observational studies find a correlation between higher levels of daily dietary potassium intake and a reduced risk of stroke and cardiovascular disease.[25][26] [27][28] However, because these studies estimate dietary potassium intake from food recall questionnaires, the direct protective effect of dietary potassium on cerebrovascular or cardiovascular risk cannot currently be proven.
Observational studies also show an association between higher levels of daily dietary potassium intake and better bone health.[29][30] Furthermore, randomized controlled trials show that supplementation with potassium improves aspects of bone metabolism in postmenopausal women with osteopenia[31][32] and in older adults with osteoporosis.[33][34] However, it is currently unclear whether supplementation with potassium prevents bone loss in such people.
Potassium-containing drugs — e.g., potassium chloride, potassium gluconate, potassium bicarbonate, potassium acetate, etc. — are used to treat low blood potassium (hypokalemia). Other potassium-containing drugs are also used clinically. For example, potassium citrate is used to treat some kidney defects, and potassium phosphate is used in the treatment and prevention of low blood phosphorus (hypophosphatemia).
A high blood potassium concentration — hyperkalemia[10] — is associated with an increased risk of heart problems (e.g., heart arrhythmias).[14][15][16][17] Hyperkalemia-related symptoms have been associated with salt substitutes in several case studies,[35][36][37][38][39] but case studies of individual people only show what is possible rather than what is typical.
In people without known health conditions, serum potassium concentrations are between 3.5 and 4.5 millimoles per liter of blood (mmol/L).[5][7][6] A meta-analysis of randomized controlled trials found that daily supplementation with potassium chloride in the range of 22 to 140 mmol/day — equivalent to approximately 0.9 to 5.5 grams/day of potassium — caused a statistically significant but clinically meaningless increase (+0.14 mmol/L) in serum potassium.[4] Therefore, generally, supplementation with potassium is unlikely to cause hyperkalemia. Furthermore, in potassium supplementation studies, adverse effects are uncommon and biomarkers of renal function (urinary and serum sodium and creatinine) are typically unaffected.[4]
While supplementation with potassium salts (e.g. potassium chloride) can improve (i.e., lower) blood pressure,[18][19][20][22][23] some evidence shows that very high doses might increase blood pressure.[24] Consequently, if you use a potassium salt to treat high blood pressure, always use the dose recommended by your doctor.
The potassium concentration in the blood is primarily regulated by the kidneys, where potassium channels (protein structures that pass potassium ions across cell membranes) in the cells of the distal tubules regulate potassium excretion in the urine.[40][5][6] Distribution of potassium within the body’s tissues is regulated by insulin, catecholamines (e.g., noradrenaline and adrenaline), and aldosterone.[5][6]
There is a steep gradient between the potassium concentration in the blood (i.e., the extracellular potassium concentration: 3.5 to 4.5 millimoles per liter, or mmol/L) and the potassium concentration in the cells (the intracellular concentration: 120 to 140 mmol/L). This gradient is critical for maintaining normal function in every cell in the body because it helps potassium ions constantly cross the cell membrane that separates the blood from the cell, generating a membrane potential. This vitally important membrane potential drives electrical impulses in neurons and contractions in muscle cells.[5][6]
This gradient is maintained by the potassium channels found in cell membranes. One of the most important is the sodium-potassium ATPase pump, which is found in every cell in the body and uses energy — adenosine triphosphate (ATP) — to maintain the potassium (and sodium) gradient across the cell membrane.[5][6]
The correlation between higher daily dietary potassium intake and a reduced risk of stroke and cardiovascular disease[25][26] [27][28] is likely explained by the blood-pressure-lowering effect of potassium.[22][23] While some evidence shows that potassium intake causes natriuresis — increased sodium excretion in the urine — and reduces vascular resistance,[6][22][41] it is not precisely understood how supplementation with potassium lowers blood pressure.
The adequate intake (AI) for potassium in people without known health conditions — i.e., the daily amount assumed to ensure nutritional adequacy — is as follows:[1]
Age | Male | Female | Pregnant | Lactating |
---|---|---|---|---|
Birth to 6 months | 400 mg/day | 400 mg/day | - | - |
Infants 7–12 months | 860 mg/day | 860 mg/day | - | - |
Children 1–3 years | 2000 mg/day | 2000 mg/day | - | - |
Children 4–8 years | 2300 mg/day | 2300 mg/day | - | - |
Children 9–13 years | 2500 mg/day | 2300 mg/day | - | - |
Teens 14–18 years | 3000 mg/day | 2300 mg/day | 2600 mg/day | 2500 mg/day |
Adult 19–50 years | 3400 mg/day | 2600 mg/day | 2900 mg/day | 2800 mg/day |
Adult 51+ years | 3400 mg/day | 2600 mg/day | - | - |
Some evidence suggests that dietary potassium insufficiency might be common: the global mean potassium intake has been estimated at 2250 mg/day, with only 35% of adults estimated to be achieving adequate intakes.[2]
Potassium is found in many foods, including fruits, vegetables, legumes, meat, and animal products.[1][3] Consult the FoodData Central database to check the amount of potassium in the foods you eat.
Potassium supplements are generally safe for consumption and are unlikely to cause adverse effects if used within the recommended dosage.[4]
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Full FAQ and database update
We fully updated this page and have several brand-new FAQs about this topic.