Potassium is found in almost every food, which is why deficiencies are unknown in healthy people. Such deficiencies are observed in patients who are starving or who have anorexia. Supplementation is rarely needed, especially in patients with advanced kidney disease who have problems regulating the amount of potassium in their bodies.
Advanced Kidney Disease
In addition to filtering the blood and removing waste products, kidneys also regulate the amount of potassium, calcium and phosphorus in the blood. When kidney function declines, the kidneys are less capable of performing this activity. Levels of these substances can build up to very dangerous levels if appropriate adjustments are not made.
Potassium and Nerves
In healthy people, the kidneys keep serum potassium levels under 5 mg/dL. This is necessary because nerves fire reliably only if concentrations of potassium on either side of the cell membrane are within certain ranges. If potassium levels get too high, nervous stimulation of heart muscle causes irregular heart beats and even heart attacks. For this reason, potassium supplements are dangerous for renal patients.
Diet
Instead of supplementing the diet with potassium, kidney patients with high potassium levels are instructed to limit their dietary potassium. Otherwise healthy foods such as bananas, apricots, bran, squash, oranges and nuts must be eaten very sparingly. In some cases, the potassium in foods like potatoes and vegetables can be leached out by cutting up the food in small pieces, soaking it in boiling water and rinsing the food before cooking.
Renal Vitamins
Since so many foods are high in potassium, patients who limit their dietary potassium can easily become malnourished. To get around this, nephrologists prescribe special renal supplements that lack potassium and other problematic nutrients such as phosphorus. By avoiding potassium supplements and minimizing dietary potassium, the dangers associated with advanced kidney disease can be minimized.
