Potassium (K+) is the principal positively charged ion (cation) in the fluid inside of cells (30 times higher than outside), while sodium (Na+) is the principal cation in the fluid outside of cells (10 times higher than inside). The concentration differences between potassium and sodium across cell membranes create an electrochemical gradient (‘membrane potential’), which is critical for nerve impulse transmission, muscle contraction, heart function, and the transport of nutrients and metabolites in and out of cells (2, 3). A large proportion of the body's resting energy expenditure is devoted to maintaining the membrane potential by ion pumps in the cell membrane, which pump sodium out of the cell in exchange for potassium.
A limited number of enzymes involved in maintaining membrane potential and carbohydrate (sugar, starch, fiber) metabolism require the presence of potassium as cofactor for their activity (2).
The European Food Safety Authority (EFSA), which provides scientific advice to assist policy makers, has confirmed that clear health benefits have been established for the dietary intake of potassium in contributing to:
