Does sodium displace potassium? I'd never heard that...did a little research. IMO, as long as you're eating a diet heavy on fresh fruits & vegs & other whole foods, there's nothing to worry about. But that's just my opinion, mind you and I've certainly been wrong before! :)
...With so many eating devitalized, heavily salted(w/sodium chloride) foods, I'll bet that potassium deficiency is widespread and that the far-ranging effects of this deficiency are unknown at this point, in fact I'll bet that it's that the potassium/sodium levels are not balanced(just thinking out loud here).
In macrobiotic theory, potassium is yin, sodium, yang. Some macrobiotic theory makes danged good sense, IMO:
Yin Foods, Yang Foods
There are four factors that determine whether a food is yin or yang:
• How the food grows (including speed and direction).
• Where the food was grown (in northern or southern climates).
• The sodium-potassium content.
• And the effect the food has on the body (hot or cold effects).
In terms of mineral elements, Yin represents foods rich in potassium,
while Yang foods are high in sodium.
In general, yin foods are considered "cool," larger, have less salt, have potassium, and/or grow above soil. Yang foods are "warm" or "hot," smaller, have more sodium, and/or grow below the soil. In addition to eating yin or yang foods, to maintain balance followers of the philosophy believe you must also eat "cool" foods when it is hot, and "hot" foods when it is cold.
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 (1).
Potassium is the principal positively charged ion (cation) 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 (2,3).