ABSTRACT
Sodium retention may be impaired in certain medical conditions, including chronic diarrhea, use of diuretics, trauma, and renal disease. The main electrolytes in the body are the cations, sodium and potassium, and the anion, chloride. Both sodium and potassium concentrations in plasma or serum may be determined by flame emission spectrophotometry, by ion-selective electrode methods or atomic absorption spectrophotometry: usually flame emission spectrophotometry or ion-selective electrode methods are employed. Measurement of the urinary excretion of sodium and potassium have been used as an indirect estimation of sodium and potassium intake. Chloride represents the main inorganic anion in the extracellular fluid compartment. Chloride is an essential component of gastric juices and in the maintenance of fluid and electrolyte balance. Excessive intakes of sodium chloride may result in edema and hypertension. Attaching nutritional significance to fluctuations in serum sodium and potassium levels is difficult and probably inconclusive due to variations resulting from certain pathological states.
