The body needs many different micronutrients to sustain life. One of these is the mineral known as potassium. While we do not often hear about a potassium deficiency, this chemical is vital for many important functions in the body. In fact with a very low potassium level, the nerves and heart cannot work properly and it may even lead to death. For most people, potassium does not need to be supplemented as there is more than enough potassium in food and in certain beverages.
What is Hypokalemia?
Hypokalemia is the medical term for low potassium levels in the blood, which is also referred to as a potassium deficiency. It is specifically when the blood potassium levels drop below 3.5 mmol/L. Hypokalemia may be mild (2.5 to 3.0 mmol/L) or severe when the potassium levels are below 2.5 mmol/L. Severe hypokalemia is a serious condition as it can be life threatening.
The nerves and muscles require potassium for transmitting electrical impulses and for contractions, respectively. Although potassium can have a wide range of effects throughout the body, one of the major risks of potassium deficiency involves the heart. It can lead to irregular heart beats (arrythmias) and the heart can even stop (sudden cardiac arrest). Death is therefore a possibility with low potassium levels in the blood.
Causes of Potassium Deficiency
The causes of hypokalemia can be divided into:
- Increased excretion of potassium, where the body loses too much of potassium through the gut, kidneys or skin (sweat).
- Shift of potassium into the intracellular space, where the potassium move outs of the tissue fluids and blood (extracellular space) into the cells (intracellular).
- Inadeqaute intake of potassium is a rare cause as a result of a potassium-deficient diet where there is insufficient potassium intake through foods and fluids.
Loss of Potassium
This is one of the more common causes of potassium deficiency. The potassium is lost through the urine, vomitus, stool or sweat. Some of the causes of excessive potassium loss, often with fluid, includes:
- Kidney diseases
- Adrenal gland dysfunction
- Diabetic ketoacidosis
- Excessive sweating
- Certain drugs like diuretics (water pills) and some types of antibiotics
- Alcohol use
- Genetic disorders
Shift of Potassium
The movement of potassium from the tissue fluids and blood into the cells can occur for the following reasons:
- Insulin administration or any other cause of elevated insulin levels.
- Eating disorders
- Prolonged starvation
- Hypothermia (low body temperature)
Insufficient dietary intake of potassium is a rare cause of hypokalemia. It is more likely to be a problem when there is excessive excretion of potassium without sufficient potassium being sourced from food and fluids. Some of the causes include:
- Poor nutrition due to eating disorders, starvation and alcoholism.
- Difficulty eating due to dental problems or immobility.
- Total parenteral nutrition (TPN) that is low in potassium.
Read more on low potassium diet.
Signs of Potassium Deficiency
The signs and symptoms of low potassium levels are due to the disturbances it causes in parts of the body that require potassium the most. There may be little to no symptoms of potassium levels that are very slightly low (hypokalemia). Very mild symptoms may be ignored.
Fatigue is one of the most common non-specific signs of potassium deficiency. However, fatigue is common in many conditions and should be attributed to potassium deficiency only if there are more specific symptoms or confirmation with a blood test.
Some of the other signs and symptoms of hypokalemia includes:
- Muscle weakness which can also manifest as:
– Shortness of breath
– Abdominal distension
- Muscle cramps and pain
- Twitching of some muscles
- Muscle breakdown (rhabdomyolysis) is a rare consequence of severe hypokalemia.
- Irregular heart rate/rhythm (arrhythmia)
The symptoms of sudden cardiac arrest and/or acute respiratory failure may also be present. These are complications of severe potassium deficiency.
Treatment of Potassium Deficiency
It is important that the underlying cause of potassium deficiency is identified once low levels of potassium in the blood is confirmed with relative diagnostic investigations. It is equally important the underlying cause is treated and properly managed. This alone may be sufficient to resolve the low potassium levels or at least prevent any further progression in the potassium deficiency.
The following treatment measures may be implemented:
- Potassium supplementation (oral or intravenous injection) is the main course of treatment for mild to severe hypokalemia. It may not always be necessary in mild cases or if the blood potassium levels are not too low and the further loss of potassium can be stopped.
- Potassium-sparing diuretics may be prescribed but only for people with normal kidney function.
- Angiotensin-converting enzyme (ACE) inhibitors may be used when hypokalemia occurs in patients using diuretics. However, it has to be used with caution as it can lead to life-threatening complications.
Replenishing potassium must be conducted with caution, especially in people with kidney diseases. At the opposite end is hyperkalemia (high potassium levels) which can sometimes be fatal. Never stop any medication that may be causing potassium deficiency unless advised by a medical doctor.
Potassium Supplement Dose
It is always advisable to take potassium supplement as prescribed by a doctor, after the relevant diagnostic investigations are completed. Adults require approximately 4,700 milligrams of potassium daily. This is easily acquire from a balanced diet. Supplementation may therefore not always be necessary to treat and manage a potassium deficiency.
Diet for Potassium Deficiency
There are many foods that have sufficient potassium to restore potassium levels. It is abundant in several different types of fruits, vegetables, dairy and meats. For example, bananas are known to be rich in potassium. However, fast foods and convenience foods may not have the same level of potassium as unprocessed foods. Preparation methods can also make a difference as boiling depleted vegetables and even meats of the potassium within it.
Read more on the DASH diet.
The DASH diet that is commonly prescribed for hypertension (high blood pressure) management is abundant in potassium. This type of eating plan may be a consideration for people who have experienced recurrent bouts of hypokalemia or are at risk of potassiu deficiency. Always be cautious about making dietary changes to increase potassium intake as this can be dangerous for some people, particularly those with kidney disease.