Potassium

Legumes—particularly cooked white (navy/cannellini) beans—are among the highest-potassium foods. Other top sources include baked potatoes with skin, dark leafy greens like spinach, avocados, lentils, and dried fruits such as apricots and raisins. A single cup of cooked white beans is one of the richest single-food potassium sources, so beans and starchy vegetables are excellent choices to raise intake.

High potassium (hyperkalemia) can cause muscle weakness, numbness, nausea and dangerous heart-rhythm changes—peaked T waves, widening QRS and arrhythmias—that may lead to cardiac arrest. Causes include kidney failure, certain medications and tissue breakdown. Severe hyperkalemia is a medical emergency treated urgently to stabilize the heart (IV calcium), shift potassium into cells (insulin+dextrose, beta-agonists) and remove it (diuretics, binders, dialysis).

Low potassium (hypokalemia) can cause muscle cramps, weakness, twitching and fatigue, plus constipation and numbness. It often produces ECG changes and can trigger dangerous heart rhythm disturbances (palpitations, arrhythmias) and, in severe cases, respiratory muscle weakness or paralysis. Causes include diuretics and vomiting; seek prompt medical evaluation and treatment if you have symptoms or an abnormal ECG.

A normal blood (serum) potassium level in adults is about 3.5 to 5.0 mmol/L. Levels below 3.5 mmol/L indicate hypokalemia and above 5.0 mmol/L indicate hyperkalemia. Both can cause muscle weakness, cramps and potentially serious heart rhythm problems. Abnormal results should be evaluated promptly by a healthcare professional for cause and treatment.

Coconut water is especially high in potassium—about 600 mg per cup (240 mL). Other potassium-rich drinks include orange juice, tomato juice, prune juice and banana smoothies. These beverages can help boost potassium intake, but watch portion sizes and added sugars. If you have kidney disease or take medications that affect potassium, consult a healthcare professional before increasing intake.

Eggs are not very high in potassium. A large egg contains only about 60 to 70 mg of potassium, far less than high‑potassium foods like bananas or potatoes. For most people, eggs contribute a small fraction of daily potassium needs, but those on potassium‑restricted diets or with kidney disease should monitor total intake and consult a healthcare professional.