Potassium is an essential mineral that has many roles in your body. It helps regulate muscle contractions, maintain healthy nerve function and regulate fluid balance.
However, a national survey found that approximately 98% of Americans are not meeting the recommended potassium intake. A Western diet is likely to blame, as it favors processed foods over whole plant foods such as fruits, vegetables, beans and nuts (1).
That said, a low-potassium diet is rarely the cause of potassium
deficiency, or hypokalemia.
Deficiency is characterized by a blood potassium level below 3.5 mmol per liter (2).
Instead, it occurs when your body suddenly loses a lot of fluid. Common causes include chronic vomiting, diarrhea, excessive sweating and blood loss (3).
Here are 8 signs and symptoms of potassium deficiency.
1. Weakness and Fatigue
Weakness and fatigue are often the first signs of potassium deficiency.
There are several ways that this mineral deficiency can cause weakness and fatigue.
First, potassium helps regulate muscle contractions. When blood potassium levels are low, your muscles produce weaker contractions (4).
Deficiency in this mineral may also affect how your body uses nutrients, resulting in fatigue.
For example, some evidence shows that a deficiency could impair insulin production, resulting in high blood sugar levels (5).
SUMMARY: Since potassium helps regulate muscle contractions, deficiency may result in weaker contractions. Also, some evidence shows that a deficiency may impair the body’s handling of nutrients like sugar, which may lead to fatigue.
2. Muscle Cramps and Spasms
Muscle cramps are sudden, uncontrolled contractions of the muscles.
They can occur when potassium levels are low in the blood (6).
Within muscle cells, potassium helps relay signals from the brain that stimulate contractions. It also helps end these contractions by moving out of the muscle cells (7).
When blood potassium levels are low, your brain cannot relay these signals as effectively. This results in more prolonged contractions, such as muscle cramps.
SUMMARY: Potassium helps start and stop muscle contractions. Low blood potassium levels can affect this balance, causing uncontrolled and prolonged contractions known as cramps.
3. Digestive Problems
Digestive problems have many causes, one of which may be potassium deficiency.
Potassium helps relay signals from the brain to muscles located in the digestive system. These signals stimulate contractions that help the digestive system churn and propel food so it can be digested (8).
When blood potassium levels are low, the brain cannot relay signals as effectively.
Additionally, some studies have suggested that a severe deficiency may cause the gut to become completely paralyzed (11).
However, other studies found that the link between potassium deficiency and a paralyzed gut is not completely clear (12).
SUMMARY: Potassium deficiency may cause problems like bloating and constipation because it can slow the movement of food through the digestive system. Some evidence shows that a severe deficiency can paralyze the gut, but it’s not completely clear.
4. Heart Palpitations
Have you ever noticed your heart suddenly beating harder, faster or skipping a beat?
This feeling is known as a heart palpitation and is commonly linked to stress or anxiety. However, heart palpitations can also be a sign of potassium deficiency (13).
This is because the flow of potassium in and out of heart cells helps regulate your heartbeat. Low blood potassium levels can alter this flow, resulting in heart palpitations (14).
In addition, heart palpitations may be a sign of arrhythmia, or an irregular heartbeat, which is also linked to potassium deficiency. Unlike palpitations, arrhythmia has been linked to serious heart conditions (14, 15).
SUMMARY: Potassium helps regulate the heartbeat, and low levels may cause symptoms like heart palpitations. These palpitations may also be a symptom of arrhythmia, or irregular heartbeat, which may be a sign of a serious heart condition.
5. Muscle Aches and Stiffness
Muscle aches and stiffness can also be a sign of a severe potassium deficiency (16).
These symptoms may indicate rapid muscle breakdown, also known as rhabdomyolysis.
Blood levels of potassium help regulate blood flow to your muscles. When levels are severely low, your blood vessels can contract and restrict blood flow to your muscles (17).
This means muscle cells receive less oxygen, which may cause
them to rupture and leak.
This results in rhabdomyolysis, which is accompanied by symptoms like muscle stiffness and aches (17).
SUMMARY: Muscle aches and stiffness can be another sign of potassium deficiency and are caused by rapid muscle breakdown (rhabdomyolysis).
6. Tingling and Numbness
Those with potassium deficiency may experience persistent tingles and numbness (18).
This is known as paresthesia and usually occurs in the hands, arms, legs and feet (19).
Potassium is important for healthy nerve function. Low blood levels of potassium can weaken nerve signals, which may result in tingling and numbness.
While occasionally experiencing these symptoms is harmless, persistent tingles and numbness may be a sign of an underlying condition. If you experience persistent paresthesia, it’s best to see your doctor.
SUMMARY: Persistent tingles and numbness may be a sign of impaired nerve function due to potassium deficiency. If you experience persistent tingles and numbness in your hands, arms, legs or feet, it’s best to see your doctor.
7. Breathing Difficulties
A severe potassium deficiency can cause breathing difficulties. This is because potassium helps relay signals that stimulate the lungs to contract and expand (20).
When blood potassium levels are severely low, your lungs may not expand and contract properly. This results in shortness of breath (21).
Also, low blood potassium can make you short of breath, as it can cause the heart to beat abnormally. This means less blood is pumped from your heart to the rest of your body (14).
Blood delivers oxygen to the body, so an altered blood flow may cause shortness of breath.
Also, a severe potassium deficiency may stop the lungs from working, which is fatal (22).
SUMMARY: Potassium helps the lungs expand and contract, so potassium deficiency may result in shortness of breath. Also, a severe deficiency may stop the lungs from working, which is fatal.
8. Mood Changes
Potassium deficiency has also been linked to mood changes and mental fatigue.
Low blood potassium levels may disrupt the signals that help maintain optimal brain function (23).
For example, a study found that 20% of patients with mental disorders had a potassium deficiency (24).
That said, there is limited evidence in the area of potassium deficiencies and mood. More research is needed before making any recommendations.
SUMMARY: Potassium deficiency has been linked to mood changes and disorders. However, the link between the two is not entirely clear.
Sources of Potassium
The best way to increase your potassium intake is by eating more potassium-rich foods like fruits, vegetables, beans and nuts.
US health authorities have set the recommended daily intake (RDI) for potassium at 4,700 mg (25).
Here is a list of foods that are excellent sources of potassium, along with the percentage of the RDI found in a 100-gram serving (26):
- Beet greens, cooked: 26% of the RDI
- Yams, baked: 19% of the RDI
- White beans, cooked: 18% of the RDI
- Clams, cooked: 18% of the RDI
- White potatoes, baked: 16% of the RDI
- Sweet potatoes, baked: 14% of the RDI
- Avocado: 14% of the RDI
- Pinto beans, cooked: 12% of the RDI
- Bananas: 10% of the RDI
SUMMARY: Potassium is found in a variety of whole foods, especially fruits and vegetables such as yams, white beans, potatoes and bananas. The recommended daily intake for potassium in the US is 4,700 mg.
Should You Take Potassium Supplements?
Over-the-counter potassium supplements are not recommended.
Taking too much potassium can cause excess amounts of it to build up in the blood, a condition known as hyperkalemia. Hyperkalemia may cause arrhythmia, or an irregular heartbeat, which can cause serious heart conditions (31).
That said, it’s fine to take a higher-dose potassium supplement if your doctor prescribes it.
SUMMARY: It’s not recommended to take over-the-counter potassium supplements, as they are limited to only 99 mg of potassium. Also, studies have linked them to adverse conditions.
The Bottom Line
Very few people meet the recommended potassium intake.
However, a low potassium intake is rarely the cause of deficiency. Deficiency typically occurs when your body loses a lot of fluid.
Common signs and symptoms of potassium deficiency include weakness and fatigue, muscle cramps, muscle aches and stiffness, tingles and numbness, heart palpitations, breathing difficulties, digestive symptoms and mood changes.
If you think you’re deficient, be sure to visit your doctor, as potassium deficiency can have serious health consequences.
Fortunately, you can increase your blood potassium levels by simply consuming more potassium-rich foods like beet greens, yams, white beans, clams, white potatoes, sweet potatoes, avocado, pinto beans and bananas.