What is potassium?
Potassium is an essential mineral that is important for maintaining fluid balance, nerve transmission, and muscle contraction. The recommended daily intake of potassium for adults is 4700mg. Potassium is found abundantly in fruits, vegetables, dairy products, and meats. Good sources include potatoes, bananas, avocados, yogurt, fish, and beans.
Why is potassium important?
Potassium has several important functions in the body:
– Regulates fluid balance – Potassium helps to regulate the amount of fluid inside and outside of cells. It works with sodium to maintain fluid balance.
– Supports nerve transmission – Potassium is important for the normal transmission of electrical impulses along nerves which allows muscles to contract and the heart to beat properly.
– Builds proteins – Potassium supports the building of proteins from amino acids. Proteins are essential for growth and repair of tissues.
– Maintains acid-base balance – Potassium helps to maintain the body’s normal pH balance which is essential for all cellular activities.
What causes low potassium levels?
There are several reasons why someone may develop low blood potassium levels (hypokalemia):
– Inadequate dietary intake – Not consuming enough potassium-rich foods can lead to hypokalemia over time. This is rare in healthy individuals but can occur in people with poor quality diets.
– Increased losses – Certain medications like diuretics, laxatives, steroids can increase urine output leading to excessive loss of potassium from the body. Vomiting and diarrhea also result in large losses of potassium.
– Impaired absorption – Gastrointestinal disorders like ulcerative colitis, Crohn’s disease can reduce the absorption of potassium from food.
– Kidney disorders – Kidney diseases or acute kidney injury can impair the kidneys’ ability to retain potassium leading to excessive urinary losses.
– Hyperaldosteronism – A condition caused by high aldosterone levels leads to increased urinary excretion of potassium.
– Diabetic ketoacidosis – A serious complication of uncontrolled diabetes leads to cellular shifts of potassium and sodium, resulting in low blood potassium levels.
What are the symptoms of low potassium?
Mild potassium deficiency may not cause any symptoms initially. As the deficiency worsens, it can cause the following signs and symptoms:
– Muscle cramps, weakness, spasms
– Fatigue, lethargy
– Constipation
– Heart palpitations
– Abnormal heart rhythms
– High blood pressure
– Pins and needles sensation
– Nausea, vomiting
– Abdominal bloating
– Depression
– Confusion
– Breathing difficulties
What are the complications of severe hypokalemia?
If left untreated, severe low potassium levels can potentially lead to dangerous complications:
– Heart arrhythmias – Abnormally low potassium disrupts the electrical signaling in the heart leading to irregular heartbeats which can be fatal. This is the most serious complication.
– Rhabdomyolysis – Extremely low potassium causes muscle cells to break down releasing cell contents into the blood which can damage the kidneys.
– Respiratory failure – Very low potassium levels affect signals between the brain and muscles needed for breathing which can cause respiratory failure.
– Dangerously low magnesium levels – Hypokalemia causes excessive urinary losses of magnesium which can drop to severely low levels.
– Increased risk of digitalis toxicity – Being on the medication digitalis while hypokalemic increases the risk of toxicity and heart arrhythmias.
How do doctors diagnose low potassium?
Doctors can diagnose hypokalemia through:
– **Blood tests** – A blood test is done to check the potassium level. Normal range is 3.5-5.0 mmol/L. Below 3.5 mmol/L indicates hypokalemia. The lower the level, the more severe the deficiency.
| Potassium level | Severity |
|---|---|
| 3.0-3.5 mmol/L | Mild hypokalemia |
| 2.5-3.0 mmol/L | Moderate hypokalemia |
| Below 2.5 mmol/L | Severe hypokalemia |
– **Electrocardiogram (ECG)** – Low potassium causes characteristic changes on an ECG like flattened T waves, depressed ST segments and presence of U waves.
– **Blood magnesium levels** – Magnesium levels are also checked as hypokalemia leads to magnesium loss.
– **Kidney function tests** – To assess if kidney dysfunction is contributing to potassium wasting.
– **Aldosterone and renin levels** – To check for hyperaldosteronism.
How is low potassium treated?
Treatment of hypokalemia involves:
– **Potassium supplements** – Potassium chloride tablets or liquid supplements are given to restore potassium levels back to normal. These are given until levels normalize and the cause of low potassium is treated.
– **Dietary changes** – A diet high in potassium-rich foods like fruits, vegetables, beans, dairy and fish is recommended.
– **Treating the underlying cause** – Any contributing factors like medications, kidney disorders or hyperaldosteronism are addressed to prevent recurrent potassium losses.
– **IV potassium** – For people with severe hypokalemia, potassium is administered intravenously under cardiac monitoring to prevent complications.
– **Medications** – Medications that lower potassium like diuretics may be reduced or stopped. Laxatives may also be stopped.
What foods are high in potassium?
The best dietary sources of potassium include:
| Food | Potassium per serving |
|---|---|
| Baked potato with skin | 920mg |
| Prunes (1⁄2 cup) | 670mg |
| Cooked spinach (1⁄2 cup) | 550mg |
| Banana | 450mg |
| Avocado | 450mg |
| Sweet potato | 450mg |
| Pistachios (1 ounce) | 290mg |
| Wild Atlantic salmon | 690mg |
| Plain yogurt (1 cup) | 550mg |
| White beans (1⁄2 cup) | 500mg |
Other good choices include leafy greens, tomatoes, carrots, oranges, apricots, nuts, seeds, fatty fish, and whole grains.
What foods should be avoided with low potassium?
People with hypokalemia may need to restrict or avoid very high potassium foods temporarily until levels normalize. Foods to limit include:
– Dried fruits like raisins, dates, prunes
– Bananas
– Orange juice or other fruit juices
– Potatoes
– Tomatoes and tomato juice products
– Packaged instant noodles which are very high in salt
– Protein or meal replacement shakes and bars that contain added potassium
Lifestyle modifications for increasing potassium
Making certain lifestyle changes can help increase potassium intake and absorption:
– Eat plenty of fresh fruits and vegetables – Aim for 8-10 servings per day. Focus on leafy greens, citrus fruits, tomatoes, potatoes, beans and bananas.
– Reduce sodium – Consuming too much sodium causes excessive losses of potassium in the urine. Limit added salt and processed foods.
– Don’t overdo fiber supplements – Too much fiber can reduce potassium absorption. Monitor intake of fiber supplements.
– Stay well hydrated – Dehydration depletes electrolyte levels. Drink adequate non-caffeinated fluids.
– Take potassium with food – Consuming potassium supplements with a meal improves absorption. Avoid taking on an empty stomach.
– Exercise regularly – Light activity helps drive potassium into cells which lowers blood levels temporarily.
When to see a doctor
Consult your doctor if you experience signs of hypokalemia like muscle weakness, cramps or heart palpitations. Seek urgent care for severe symptoms like chest pain, difficulty breathing, severe vomiting or very low energy. Chronic hypokalemia requires medical management to treat the underlying disorder and replenish potassium safely. Do not self-medicate with potassium supplements without medical guidance.
Conclusion
Potassium is a vital nutrient that is essential for heart, muscle and nerve function. The body is unable to store reserves of potassium and levels are tightly regulated by the kidneys. Hypokalemia or low blood potassium develops due to inadequate dietary intake, impaired absorption, increased losses through the urine or a combination. Mild deficiency may cause very subtle symptoms but severe hypokalemia can be life-threatening. Treatment involves potassium supplementation along with modifying the diet and any contributing medical conditions. With prompt management, potassium levels can generally be restored back to normal relatively quickly.