Potassium is a chemical element essential to the body. It plays a major role in helping the heart function properly. The variation of kalemia, i.e. the level of potassium in the blood, can have many causes and consequences.
What is potassium?
Potassium is part of the body’s electrolytes. Electrolytes are minerals that carry an electrical charge when dissolved in body fluids, such as blood.
Potassium is present in the cells, but also in the blood, where it plays key roles. A potassium level that is too high (hyperkalemia) or too low (hypokalemia) in the blood can lead to many complications, especially ones related to the heart. In order to regulate blood levels, the body can use the vast stock of potassium inside the cells.
The word potassium comes from the Latin “kalium”, which is why it is represented by the symbol K. Its level in the blood is called kalemia.
The potassium balance is maintained by controlling the amount of potassium supplied (diet and treatments) and the amount discharged (in the urine). Potassium is absorbed from foods and beverages that contain potassium. It is mainly eliminated through the work of the kidneys, in the urine. A small portion is also lost in sweat and the digestive tract. Healthy kidneys allow the level of potassium eliminated to vary to adapt to differences in consumption.
What is the normal level of potassium in blood?
Kalemia is the level of potassium in the blood and is assessed by taking a blood sample. In men, women and children, the blood potassium level is considered normal when it is between 3.5 (63mg/dL) and 5 mmol/l (90mg/dL).
The needs may be higher in athletes (who eliminate a greater part by sweating), people with high blood pressure, postmenopausal women, alcoholics, people who do not eat enough fresh fruit and vegetables, people on certain medications or regularly using laxatives, people with kidney disease.
Nowadays, salt consumption is constantly increasing, in particular due to the rise in consumption of industrial foods. This is to the detriment of potassium consumption, especially with the decline in the consumption of fruits and vegetables. As a result, this inversion of the sodium-potassium ratio unfortunately causes imbalances in our organism, which can have repercussions on our health.
What is the role of potassium in the blood?
Most of the body’s potassium is located inside the cells. Therefore, potassium is essential for the normal functioning of cells, nerves and muscles.
Potassium plays an essential role in the body’s acid-base balance, helping to neutralize the acids metabolized after meals.
It also plays an important role in the synthesis of carbohydrates from liver and muscle stores (glycogenesis) and in protein synthesis.
Also, potassium is involved in the transmission of nerve impulses. Therefore, it is essential for muscle contraction.
Finally, potassium helps to regulate blood pressure. Thus, it makes it possible to compensate for the negative effects of an excess of sodium in order to reduce high blood pressure.
What are the symptoms of too much potassium?
What is hyperkalemia?
Often, hyperkalemia is due to several problems occurring simultaneously, including :
- The presence of kidney disorders, they prevent the kidneys from eliminating potassium in sufficient quantities.
- Taking medication, the medicine may prevent the kidneys from eliminating normal amounts of potassium.
- Consumption of potassium-rich foods
- Taking treatments that contain potassium
The most common cause of mild hyperkalemia is the use of medicines that reduce the blood flow to the kidneys. Or those that interfere with the excretion of normal amounts of potassium in the urine.
Some diseases can also lead to hyperkalemia: kidney failure and Addison’s disease.
It should be noted that increased potassium intake rarely causes hyperkalemia because healthy kidneys are efficient enough to reject excess potassium. It is especially the too little potassium in relation to sodium that is problematic.
What are the symptoms?
Moderate hyperkalemia rarely causes symptoms, so it is often asymptomatic. Sometimes it is associated with muscle weakness. In its severe form, hyperkalemia can lead to disturbances in the heart rhythm. If the level of potassium in the blood is really very high, then cardiac arrest may occur.
What are the risks of potassium deficiency?
What are the causes of hypokalemia?
Generally, potassium levels drop sharply after repeated digestive problems such as vomiting, diarrhea or overuse of laxatives. In this case, the loss of potassium is too high and potassium levels become too low for the body: this is called hypokalemia.
Some diseases that cause disorders of the adrenals, such as Cushing’s syndrome, increase the excessive production of aldosterone. It is a hormone that induces the elimination of large amounts of potassium in the kidneys and thus hypokalemia.
Some treatments, such as insulin, salbutamol and terbutaline, also cause hypokalemia. They increase the amount of potassium that is moved from the blood to the cells, drastically lowering the levels of potassium in the blood. However, these drugs usually result in transient hypokalemia unless another condition also causes increased potassium loss.
What are the symptoms of hypokalemia?
A slight decrease in kalemia is usually asymptomatic.
A greater decrease in blood potassium levels leads to weakness, contractions and even muscle paralysis.
Heart rhythm disturbances can also occur if there is an imbalance in the kalemia. They can occur even if the decrease in this rate is small. This is seen in people who already have a heart condition or who are taking digoxin, a medication for heart problems.
If hypokalemia lasts for a prolonged period, kidney problems may appear. This leads to a more frequent need to urinate and an increased desire to drink large amounts of water.
What are the foods to limit in case of hyperkalemia?
Here is the list of foods richest in potassium, up to 3.7g (0,13oz) per 100g (3,5oz) of food:
- Dehydrated Algae
- Soluble coffee, teas and spices
- Dried tomatoes, tomato paste
- Food yeast
- Milk powder
- Dried fruits (apricots, grapes, bananas)
- Rice bran, wheat bran
- Dark chocolate
- Oleaginous fruits (hazelnuts, almonds, pistachios)
- Potatoes (cooked, dehydrated flakes, chips), Yam
- Seeds (flax, pine nut, poppy)
What are the foods to favour in case of hyperkalaemia?
Here is a list of foods low in potassium:
- Oils, butter
- Rice vermicelli, the rice
- Dairy products
- Egg yolk
Article written by Romane, Dietician at Foodvisor.