Potassium is an essential mineral and electrolyte (facilitates the transport of electrical charges) that is crucial for numerous bodily functions and cellular functionality. They depend on the regulation of potassium concentrations inside and outside the cells 1. Potassium is involved in nerve signal transmission, fluid balance, and muscle contractions, among other things.
An adult human body contains 1.6 to 2 grams of potassium per kilogram of body weight 2. For example, in adulthood, a 55 kg woman would have 88 to 110 grams of potassium, and an 80 kg man would have 128 to 160 grams. Potassium is predominantly found inside cells in the body (98% intracellular, 2% extracellular) 3.
The main function of potassium, which is present in every cell, is the regulation and maintenance of water and electrolyte balance. Potassium, along with sodium and chloride, is responsible for regulating osmotic pressure, which refers to the water content of cells.
This mineral ensures sufficient water supply to the cells. Water serves as a binding agent, holding the cell structure together, and is also required for biochemical processes such as the transport of nutrients and their waste products. Additionally, potassium has diuretic and water-draining effects.
Potassium helps other nutrients enter the cells and aids in the removal of waste products from the cell 4.
- Transmission of electrical impulses (nerve signaling)
- Regulation of pH balance (acid-alkaline equilibrium in the body)
- Aids in carbohydrate metabolism (energy release)
- Cofactor for enzymes (including pyruvate kinase, an important enzyme for carbohydrate metabolism)
- Protein synthesis (formation of proteins)
- Involved, along with magnesium, in maintaining rhythmic heart function and proper contraction of cardiac muscle cells
Potassium may also be involved in the regulation of cell growth 8.
The potassium concentration inside the cells is about 150 mmol/L, while outside the cells it ranges from 3.5 to 5.5 mmol/L 9. For sodium, it is 10 mmol/L intracellularly and 140 mmol/L extracellularly. This creates a concentration gradient between the intra- and extracellular compartments, which is necessary for the generation and transmission of nerve impulses. The sodium-potassium pump (Na/K-ATPase) maintains the concentration gradient of potassium and sodium (negative membrane potential inside the cell). This membrane potential is essential for cell excitability, muscle contractions, and impulse transmission. Persistent changes in this gradient can lead to life-threatening complications. Insulin is required for the activation of the sodium-potassium pump 10.
When a nerve impulse (action potential) arrives to contract the muscles, sodium enters the cell, and potassium exits. This smooth process is particularly important for athletes to maintain optimal performance.
Potassium for Healthy Bones
Scientists have found that potassium contributes to bone health and reduces the risk of osteoporosis. 11. Potassium salts (bicarbonate and citrate) decrease the breakdown of bone tissue (osteoporosis), thereby preserving bone strength. 12.
At the same time, increased potassium intake results in reduced calcium excretion through urine, which may have benefits on bone health. 13. Additionally, a diet rich in potassium salts also leads to lower acid excretion since they are neutralized in the body beforehand, thus preserving bone tissue.
A higher potassium intake helps lower blood pressure. According to a summary of studies, increased potassium intake has blood pressure-lowering benefits in people with hypertension. 14. Potassium has been shown to counteract the negative effect (elevated blood pressure) caused by excessive sodium intake. 15 16. It is not recommended to supplement with potassium as there is currently no evidence of blood pressure-lowering benefits from such supplements. 17.
The potassium derived from food can also help prevent strokes due to its blood pressure-lowering benefit. 18 19. There is some promising evidence that foods containing at least 350 mg of potassium per serving, as well as low sodium and a low proportion of saturated fats, can reduce the risk of stroke. 20. According to a summary of studies, higher intakes of potassium are associated with a significantly reduced risk of strokes in women. 21. Another summary of studies involving a total of 247,510 subjects showed that the risk of stroke could be reduced by 21% with an additional 1.64g (42 mmol/day) of potassium. 22. Scientists also suggest that potassium may reduce the risk of cardiovascular diseases and coronary heart disease. 23.
Since increased potassium intake reduces calcium excretion through urine, potassium also plays an important role in controlling hypercalcemia (elevated blood calcium levels) 24. Additionally, it reduces the risk of osteoporosis 25 26. Several studies have shown that higher potassium intake is associated with a reduction in kidney stones 27 28.
Potassium for Athletic Performance
Since potassium is involved in the transmission of nerve impulses, it also plays an important role in muscle contractions, especially in heartbeat. Additionally, potassium is needed for protein synthesis and muscle development 29.
Potassium is required, like water, for storing glycogen in the muscles. Glycogen is the storage form of glucose. Before a physical exertion, the stores are full. During training or competition (approximately 60 to 90 minutes), the stores become depleted and serve as an energy source. During this process, potassium is lost through sweat or partially moves back from the cells into the extracellular space 30. As a result, blood potassium levels rise. If potassium is consumed during exertion, the levels further increase, creating an imbalance between the intracellular and extracellular compartments. Therefore, it is advisable to consume potassium-rich foods and beverages during the recovery period to replenish glycogen stores. However, during prolonged exertion exceeding one hour, some potassium should be supplied (e.g., banana and orange juice) to prevent cramping, fatigue, exhaustion, and irregular heart rhythms 31.
Sodium Affects Potassium Excretion
If more sodium (including excessive intake of salty foods) is consumed through diet, the body retains more potassium to counterbalance the negative effects of a sodium-rich diet, such as high blood pressure 32. Therefore, it is important to maintain a good potassium-to-sodium ratio. High sodium intake and low potassium intake significantly increase the risk of mortality and cardiovascular diseases 33 34.
Are there any considerations for vegans?
According to several studies, vegans have higher potassium levels compared to the general population. 35 36 37. Healthy vegans do not need to worry about adequate potassium intake with a varied diet. For foods rich in potassium, click here.