Potassium is a chemical element with the symbol K and atomic number 19. It is an alkali metal and, in the body, an essential electrolyte.
Elemental potassium is highly reactive and is not found free in nature. In food and the human body it is present as potassium ions in salts and solution, not as metallic potassium.
Element
The Royal Society of Chemistry lists potassium as a group 1 element, solid at 20 C, with relative atomic mass 39.098. The metal is soft and reacts vigorously with water, so it is normally stored away from air and moisture.
Potassium compounds are used in fertilisers, glass, soaps, chemicals and many industrial processes. Potash minerals are an important source of potassium for agriculture.
Nutrition and Physiology
Potassium is important for fluid balance, nerve signals, muscle contraction and heart rhythm. It works with sodium and other electrolytes to maintain electrical gradients across cell membranes.
Dietary sources include potatoes, beans, lentils, fruit, vegetables, milk, yoghurt, fish and meat. The NIH Office of Dietary Supplements notes that potassium is present in a wide variety of foods.
Low and High Potassium
Low blood potassium is called hypokalaemia. It can be caused by vomiting, diarrhoea, some diuretics, poor intake or medical conditions. Symptoms can include weakness, cramps, constipation and abnormal heart rhythm.
High blood potassium is called hyperkalaemia. It is more likely in kidney disease or with some medicines. Severe hyperkalaemia can affect heart rhythm and needs urgent medical care.
See Also
References
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