“Eat a banana. They’re good for you.” We’ve all probably heard this at some point in our lives and accepted it without question. But why are bananas good for you? In addition to being low in calories and high in fiber and various vitamins, bananas contain an important mineral that is crucial for numerous aspects of health: potassium. Potassium can be found in many different fruits, vegetables, and animal products, and therefore it’s pretty hard to develop a deficiency. In the rare case where a person does experience a deficiency of potassium, however, this is called hypokalemia.

What Is Hypokalemia?

Rather than being a specific medical condition, hypokalemia is simply the term used to indicate low blood serum potassium levels. In the regular course of life, it’s natural to have a mild deficiency of any kind of nutrient from time to time without it causing any clinical manifestations. The same is true for low potassium: in most cases, mild hypokalemia won’t cause symptoms or lead to other medical problems. It’s only when it persists or becomes a more severe case when symptoms start to emerge.

Potassium is a chemical element that is considered an essential nutrient because of the many different ways it is used by the body. As a type of electrolyte, it is a substance that has an electrical charge when dissolved in water and is involved in the function of nerve cells, muscle cells, and the regulation of heart rhythm. One of its most important functions, though, is to maintain the balance of fluids inside cells (intracellular) and between cells (extracellular) and to counteract the presence of excess sodium in the bloodstream.

The Food and Drug Administration (FDA) recommends that adults and children over the age of 4 get 4700 mg of potassium each day through dietary sources; that equates to normal blood potassium levels of 3.7 to 5.2 milliequivalents per liter. Overall, most people consume far less than that amount of potassium on a daily basis, which can mostly be explained by changes to the American diet over the last several decades. Processed foods, which make up a significant proportion of the food we eat, tend to be high in sodium and low in potassium.

Common Symptoms of Hypokalemia

Also sometimes referred to as hypokalemic syndrome or potassium intake deficiency, hypokalemia is a relatively common occurrence that affects around 11% of the population of the United States. In fact, research shows that low body potassium concentration has been on the rise for the last 20 years. Yet not everyone has symptoms, and those that do can experience a wide variety. Below are some common symptoms of hypokalemia:

A low level of potassium generally also means a higher level of sodium in the bloodstream; while the body also needs sodium to function, too much can lead to fluid retention and increased blood pressure. Higher blood pressure is then additionally linked to a number of other conditions, including heart palpitations, arrhythmia, and even problems with the kidney. These complications are typically only associated with severe hypokalemia and are therefore relatively rare in the general population.

Common Causes of Hypokalemia

Since there are many reasons why a person’s blood potassium levels might be lower, hypokalemia can’t be attributed to a single underlying cause. Apart from not getting enough potassium in one’s diet, it is also regularly lost through sweat, urination, and defecation. Yet there are various conditions that can affect body potassium. Below are some common causes and risk factors that have been identified:

  • Diuretics: Diuretics are medications that increase the production of urine, which is useful in the treatment of heart failure, kidney disease, and a number of other conditions. By increasing urine production, however, diuretics can also cause the excess secretion of potassium.
  • Laxatives: Laxatives are used to loosen stools and increase the motility and regularity of bowel movements. Long-term or excessive use of laxatives can cause chronic diarrhea and the resultant loss of fluids and electrolytes like potassium.
  • Low magnesium or calcium: Having low magnesium levels (hypomagnesemia) or calcium levels can’t cause low potassium levels, but deficiencies in one tend to occur at the same time as deficiencies in the others.
  • Chronic kidney disease: As noted above, potassium is normally removed from the body through the urinary system, but it first has to pass through the kidneys. For people with kidney disease, the ability to balance potassium levels is compromised; this can lead to either low potassium levels or high potassium levels (hyperkalemia).
  • Bartter syndrome: Bartter syndrome is a rare genetic disorder that affects the kidneys’ ability to reabsorb sodium, potassium, and other electrolytes, leading to excessive salt and water loss in the urine.
  • Cushing’s syndrome: Cushing’s syndrome is a condition caused by prolonged exposure to high levels of cortisol, a hormone produced by the adrenal glands. Higher cortisol levels additionally leads to lower potassium levels.
  • Diabetic ketoacidosis: Diabetic ketoacidosis is a serious and potentially life-threatening complication of diabetes that occurs when blood sugar levels are consistently high; this causes the body to use fat for energy and the resulting ketone production increases acidity in the body. The medications used to treat the condition can subsequently cause a depletion of potassium levels.
  • Gitelman syndrome: Gitelman syndrome is a rare genetic disorder that affects the kidneys’ ability to reabsorb certain electrolytes, including magnesium and potassium.
  • Renal tubular acidosis: Renal tubular acidosis is a disorder characterized by the kidneys’ inability to properly maintain the acid-base balance in the body. The condition can similarly affect the balance of potassium and sodium.

    How Is Hypokalemia Diagnosed and Treated?

    If hypokalemia is suspected based on symptoms or because of the presence of another condition known to be associated with hypokalemia, the first step is usually to take a blood test. The blood test will show blood serum potassium levels, and anything lower than 3 to 3.5 mmol/L of potassium is considered a problem that requires treatment. In some cases a urinalysis may also be done, and if necessary an electrocardiogram (ECG) may be ordered to look for abnormalities in the heart rate.

    For most mild cases of hypokalemia, treatment may not be necessary. If symptoms have started to present, though, the doctor will prescribe oral potassium supplements to bring levels back to normal. If the case is more severe, the doctor may have to use intravenous supplements instead. For recurrent or treatment-resistant cases of hypokalemia, the doctor may also prescribe a type of diuretic that is designed to increase the production of urine while also retaining potassium.

    Cary Gastro: Experts in Gastrointestinal Healthcare

    There are many possible causes of a potassium deficiency, and it is a more common problem than most people realize. While it isn’t a typical gastrointestinal concern, the symptoms and potential complications often stem from or result in issues related to the digestive system. If you’ve been experiencing gastrointestinal symptoms and are looking for an expert perspective, the board certified physicians at Cary Gastro are available to help. Please contact us today to request an appointment.