In normal individuals, however, there is not reason to suspect that deficiency may exist despite a normal reading. When potassium deficiency does occur, the cause often in not poor food choices, but rather specific medical conditions. In order to develop potassium deficiency, the body must lose more than it takes in. Typical conditions allowing this to happen include chronic diarrhea or vomiting, alcoholism, anorexia nervosa, and other illnesses causing severe loss of appetite. Diabetics whose condition progresses to the state called ketoacidosis are at risk of potassium deficiency.
Cystic fibrosis can lead to excessive loss of potassium due to loss in sweat.
Some forms of kidney impairment predispose these individuals to potassium deficiency. A once common practice was to supplement the diet with potassium if one was taking a diuretic. However, some diuretics actually keep potassium in the body and supplementation could be a dangerous practice when used routinely with all diuretics. Carbenicillin, an antibiotic given by injection, has been associated with an increased risk of potassium deficiency. Infants and children are at most risk of deleterious accidental overdose with potassium.