Potassium is a macro (major) mineral.
    Potassium is an essential dietary mineral that is also known as an electrolyte. The term electrolyte refers to a substance that dissociates into ions (charged particles) in solution making it capable of conducting electricity. The normal functioning of our bodies depends on the tight regulation of potassium concentrations both inside and outside of cells.

A limited number of enzymes require the presence of potassium for their activity. The activation of sodium, potassium-ATPase requires the presence of sodium and potassium. The presence of potassium is also required for the activity of pyruvate kinase, an important enzyme in carbohydrate metabolism.

Adults should have 4.7 grams every day.

Intake:

Recommended Dietary Allowance (RDA) for Potassium
Babies 0-6 months	400 mg/day
Babies 7-12 months	700 mg/day
Children 1 to 3 years	3000 mg/day
Children 4 to 8 years	3800 mg/day
Children 9 to 13 years	4500 mg/day
Teenagers 14 to 18	4700 mg/day
Adults ages 19 and older	4700 mg/day
Pregnant women	4700 mg/day
Breast-feeding	5100 mg/day

Maintenance of membrane potential Potassium is the principal positively charged ion in the fluid inside of cells, while sodium is the principal cation in the fluid outside of cells. Potassium concentrations are about 30 times higher inside than outside cells, while sodium concentrations are more than 10 times lower inside than outside cells. The concentration differences between potassium and sodium across cell membranes create an electrochemical gradient known as the membrane potential. A cell's membrane potential is maintained by ion pumps in the cell membrane, especially the sodium, potassium-ATPase pumps. These pumps use ATP (energy) to pump sodium out of the cell in exchange for potassium (diagram). Their activity has been estimated to account for 20%-40% of the resting energy expenditure in a typical adult. The large proportion of energy dedicated to maintaining sodium/potassium concentration gradients emphasizes the importance of this function in sustaining life. Tight control of cell membrane potential is critical for nerve impulse transmission, muscle contraction, and heart function.

The richest sources of potassium are fruits and vegetables.