Potassium deficiency can occur if a person does not get enough potassium from their diet or loses too much potassium through prolonged diarrhea or vomiting. The symptoms depend on the severity of the deficiency but can include high blood pressure, constipation, kidney problems, muscle weakness, fatigue, and heart issues.
Potassium is an essential nutrient that the body requires for a wide range of functions, including keeping the heart beating. Severe potassium deficiency is called hypokalemia, and it occurs when a person's potassium levels fall below 3.6 millimoles per liter (mmol/L).
Doctors consider a person to have severe hypokalemia — a potentially life-threatening condition — when their potassium levels are less than 2.5 mmol/L.
In this article, we describe some of the possible symptoms of potassium deficiency. We also cover when to see a doctor, diagnosis, treatment, and potassium food sources.
Potassium plays an important role in relaying messages from the brain to the muscles and regulating muscle contractions. Low potassium levels can affect the muscles in the intestines, which can slow the passage of food and waste. This effect on the intestines can cause constipation and bloating.
Potassium deficiency can affect other muscles in the body, including those in the arms and legs, which can lead to general muscle weakness and cramping.
A person loses small amounts of potassium through sweat, which is why heavy sweating from intense physical activity or being in a hot climate can often lead to muscle weakness or cramping.
Potassium is an essential nutrient that is present in all of the body's cells and tissues. When potassium levels fall, this can significantly affect a wide range of bodily functions, which can lead to low energy levels and both physical and mental fatigue.
Low potassium levels can lead to an increase in blood pressure, particularly in people with a high sodium, or salt, intake. Potassium has an important role in relaxing the blood vessels, which helps lower a person's blood pressure.
Potassium also helps balance sodium levels in the body. A diet high in sodium is a common cause of high blood pressure. Doctors often recommend that people with high blood pressure lower their sodium intake and increase their potassium intake.
The kidneys are responsible for removing waste products and regulating the levels of fluids and electrolytes, such as sodium and potassium, in the blood. They do this by passing waste and excess electrolytes out of the body in the urine.
Moderate-to-severe hypokalemia can interfere with the kidneys' ability to balance fluid and electrolyte levels in the bloodstream, and this can lead to increased urination, which is called polyuria.
People with severe hypokalemia can experience muscle paralysis. When the levels of potassium in the body are very low, the muscles are unable to contract properly and may stop working altogether.
Severe hypokalemia can also lead to breathing problems. Breathing requires the use of several muscles, particularly the diaphragm. If a person's potassium levels become very low, these muscles may not work properly. A person may have difficulty taking a deep breath or may feel very short of breath.
Another symptom of severe hypokalemia is an irregular heart rhythm. Potassium plays an important role in regulating the contractions of all muscles, including the heart muscle.
Very low levels of potassium in the body can lead to irregular heart rhythms, including sinus bradycardia, ventricular tachycardia, and ventricular fibrillation. If a person does not receive treatment, these conditions can be life-threatening.
Doctors can detect irregular heart rhythms using an electrocardiogram (EKG).
People with symptoms of hypokalemia should see a doctor.
Hypokalemia is more common in people with inflammatory bowel disease (IBD) and gastrointestinal illnesses that cause severe or persistent diarrhea or vomiting. Certain medications, such as laxatives and diuretics, can also increase the risk of potassium deficiency.
It is important to seek immediate medical attention for symptoms of severe hypokalemia, such as muscle paralysis, breathing problems, or irregular heart rhythms.
A doctor can perform a simple blood test to determine a person's potassium levels. The test involves taking a small blood sample from a vein in the hand or arm.
To determine the underlying cause of potassium deficiency, a doctor will also review the person's medical history and any medications that they are taking.
The doctor may sometimes recommend additional tests, including:
- further blood tests to check the levels of other electrolytes, such as phosphorous, calcium, and magnesium
- urine testing to determine how much potassium is passing out of the body
Further tests may be necessary depending on the person's medical history and symptoms.
The type of treatment for potassium deficiency will depend on a person's symptoms and how low their potassium levels have become.
For people with mild hypokalemia, a doctor may recommend:
- stopping or reducing the dosages of any medicines that can cause low potassium
- taking daily potassium supplements
- eating more foods rich in potassium, such as fruits and vegetables
- taking medications that can increase potassium levels in the body, such as angiotensin converting enzyme inhibitors or angiotensin receptor blockers
People with severe hypokalemia require immediate treatment, and a doctor may recommend intravenous potassium. However, doctors need to be careful when prescribing hypokalemia treatments as it is possible to provide a person with too much potassium, leading to excessive potassium levels in the body, or hyperkalemia.
Severe hyperkalemia can also cause serious muscle and heart problems.
According to the Office of Dietary Supplements, the recommended daily intake of potassium is:
- 3,400 milligrams (mg) for adult males
- 2,600 mg for adult females
Potassium occurs naturally in a wide range of foods, including fruits, vegetables, meats, dairy products, nuts, and whole grains. The body absorbs around 85 to 90% of the potassium in food sources.
Examples of foods rich in potassium include:
- dried apricots: 1,101 mg per half cup
- cooked lentils: 731 mg per cup
- dried prunes: 699 mg per half cup
- orange juice: 496 mg per cup
- banana: 422 mg in a medium-sized banana
- 1%-fat milk: 366 mg per cup
- spinach: 334 mg per 2 cups
- nonfat fruit yogurt: 330 mg per 6 ounces
- cooked, chopped broccoli: 229 mg per half cup
- cooked brown rice: 154 mg per cup
The best way for a person to get enough potassium is to eat a varied and healthful diet.
Potassium deficiency, or hypokalemia, can occur if a person does not get enough potassium from their diet. Severe vomiting or diarrhea, IBD, and certain medications can increase the risk of deficiency.
The symptoms of hypokalemia depend on the severity of the deficiency, but they can include constipation, muscle problems, fatigue, and heart issues. Severe hypokalemia can be life-threatening if a person does not receive treatment.
The best way to get enough potassium is to eat a varied diet that includes plenty of fruits and vegetables.