Potassium - consequences of an imbalance in the body
The mineral potassium plays an important role in the human organism. It is also called the "heart mineral" because it is essential for the proper functioning of our heart. The causes for changes in the potassium balance are manifold; they can occur, for example, as a side effect of medicines. But one thing is certain: a potassium level that is severely elevated or depressed in the long term is associated with serious physical and mental impairments.
Why does our body need potassium?
Potassium is responsible for regulating blood pressure, water balance and the excitability of nerve and muscle cells. The mineral, in interaction with calcium and sodium, affects heart muscle activity. Potassium also plays a role in carbohydrate metabolism, i.e. it is important for energy production. According to the reference values of the German Nutrition Society (DGE), the requirement for adults is about 4,000 mg a day. Since potassium is contained in many foods, most people's needs are easily covered by their diet. Grains, nuts, dark chocolate, tomatoes, mushrooms, carrots, bananas, apricots and dried fruit are particularly rich in potassium. However, the potassium concentration in the body is regulated not only by absorption through food but also through excretion. In healthy people, about 90 per cent of this happens through the kidneys and about 10 per cent through stool and sweat.
The minerals potassium and sodium are closely related. Our ancestors consumed more than five times as much potassium as sodium because they ate an exclusively natural diet. Because of the modern civilised diet, it is now the other way round: we consume much more sodium in our diet than potassium. This unfavourable nutrient ratio can trigger high blood pressure.
How dangerous is a too high potassium level (hyperkalaemia)?
In hyperkalaemia, the concentration of potassium in the blood is too high. Certain diseases influence the potassium balance, such as acidosis (disturbance of the acid-base balance) or kidney insufficiency. Impaired kidney function leads to reduced potassium excretion and thus to excess potassium. Hyperkalaemia can also occur after extensive burns (due to the decay of red blood cells) or temporarily during infusion therapy. Even blood pressure-lowering or dehydrating drugs can lead to elevated levels. Unfortunately, an excess is often recognised late, sometimes only after cardiovascular arrest has occurred. Possible early signs include a furry feeling on the tongue, skin tingling, ringing in the ears, paralysis, muscle weakness and muscle twitching. Long-term potassium excess can lead to cardiac arrhythmias and subsequently cardiac arrest. Hyperkalaemia is rare. However, if it remains untreated, it is life-threatening for humans. Potassium deficiency is more common in practice. Reason: If the potassium level is too high, the kidney can accelerate excretion to a certain degree. However, it is more difficult to curb excretion because the potassium level is too low.
How does a potassium deficiency (hypokalaemia) occur?
Causes of a potassium deficiency can be excessive vomiting or diarrhoea, the misuse of laxatives, excessive salt consumption or inflammatory bowel diseases. Similarly, an undersupply can result from malnutrition, malnutrition or an unmet increased need. In diabetics who have to inject insulin, too, potassium is transported more into the cells and is thus lacking in the blood. A mild potassium deficiency is often detected by chance during a blood test, because it only shows very unspecific symptoms, such as tiredness, weakness, dizziness, headaches, nervousness, constipation, hair loss or dry skin. Only when there is marked hypokalaemia do more typical symptoms appear. The regulation of muscle contraction is one of the most important functions of potassium. If this function is permanently disturbed due to a potassium deficiency, this can have dangerous consequences for our heart: Heart rhythm disturbances occur, which can go as far as ventricular fibrillation or cardiac arrest. In addition, potassium can no longer have a regulating effect on blood pressure, which increases the risk of a stroke.
Risk groups for a potassium deficiency are especially people with cardiovascular diseases and hypertension patients. But old age can also favour the development of hypokalaemia. The appetite of senior citizens often decreases with age. As a result, they may eat too little and only insufficiently cover their potassium needs. In addition, older people are more likely to take dehydrating medication. In addition, the digestive system's ability to dissolve nutrients from food decreases. Together, these three factors increase the risk of deficiency.
What to do if the values are increased or decreased?
Especially for patients suffering from kidney disease, potassium oversupply is life-threatening. If medicines are responsible for the disorder, they are discontinued or replaced by other preparations. This usually reduces the symptoms within a short time. It is also important for affected patients to drink a lot. This keeps the kidneys well flushed, which makes their work much easier. Older people in particular have to make sure they drink enough, because for many people the feeling of thirst is less pronounced. The optimal amount is 1.5 to 2 litres of still water, fruit and herbal teas or diluted juices per day. How a potassium deficiency is treated depends on the cause. A deficiency caused by malnutrition can be remedied with a potassium-rich diet. Dietary supplements are only recommended after consultation with a doctor, because an excessive intake can lead to an undesired excess of potassium. In addition, there may be interactions with other medicines. If the potassium level is too low in the long term, a medically supervised long-term therapy is required. If there is an acute risk of heart attack due to hypokalaemia, doctors use electrolyte infusions, which contain potassium chloride as well as other components.
A blood test provides information
A disturbed potassium level is often detected by a routine blood count check at the doctor's office. If there is a concrete suspicion, the diagnosis is made on the basis of a laboratory examination. For this purpose, the potassium values are determined together with sodium, calcium, chloride and other enzyme values. The blood plasma usually has concentrations between 3.5 and about 5.0 mmol/l (millimoles per litre). If the potassium level is below 3.5 mmol/l, it is called hypokalaemia; if it is above 5.5 mmol/l, it is called hyperkalaemia. Potassium can also be measured in the urine. Here, the normal value (in 24-hour collected urine) is about 30 to 100 mmol/24h. If an excess of potassium is detected, regular monitoring of the blood level is necessary so that countermeasures can be taken immediately if necessary. Since a disturbed potassium balance can trigger cardiac arrhythmias, an ECG (electrocardiogram) is made in case of suspicion. This allows the doctor to recognise typical changes in the electrical conduction.
Conclusion
An excess of potassium in the organism is mainly caused by an underlying disease. Therefore, the cure of hyperkalaemia depends strongly on the diagnosis and treatment of the underlying disease. As a patient, you can support the process by changing your lifestyle. With an adapted diet and sufficient drinking quantity, the kidney function is positively influenced and strengthened. A slight potassium deficiency can be easily remedied by eating potassium-rich foods. If you are unsure and before taking potassium supplements, it is advisable to visit your doctor. He can carry out all the necessary examinations and recommend an individual therapy.
