Potassium deficiency, or hypokalemia, happens when your blood potassium level drops below 3.6 mmol/L. This often results from diarrhea, vomiting, or excessive diuretic use. Severe cases can cause muscle weakness, heart palpitations, and even paralysis.
Your body tightly regulates potassium levels through dietary intake, cellular uptake, and excretion via urine and sweat. Deficiencies arise when output exceeds intake or when cells absorb too much potassium from the bloodstream. Chronic kidney disease can also impair potassium regulation.
The most common causes fall into three categories:
Certain groups face higher risks of developing potassium deficiency:
| Risk Factor | Explanation |
|---|---|
| Diuretic use | Loop and thiazide diuretics increase urinary potassium excretion |
| Chronic diarrhea | Frequent bowel movements prevent adequate potassium absorption |
| Malnutrition | Insufficient nutrient intake from poor diet or eating disorders |
| Alcoholism | Chronic alcohol use damages kidneys and impairs potassium regulation |
Mild deficiencies may cause fatigue, muscle weakness, or constipation. Severe cases can lead to paralysis, respiratory failure, or life-threatening heart arrhythmias. A study in the Journal of the American Society of Nephrology found that chronic hypokalemia increases the risk of kidney disease progression.
I once treated a patient with persistent fatigue who was taking a diuretic for hypertension. Blood tests revealed severe hypokalemia, which resolved after adjusting medication and adding potassium-rich foods to their diet.
Most people get enough potassium from bananas, sweet potatoes, and leafy greens. Severe deficiencies require oral supplements or intravenous potassium replacement under medical supervision. The Mayo Clinic recommends monitoring potassium levels in people at high risk.