Effects of alcohol on electrolytes and minerals

Effects of Alcohol on Electrolytes and Minerals

Electrolytes and minerals are involved in most cellular activities and assume a major role in metabolism. They have multiple functions such as holding fluids in compartments of the body and maintaining normal acid-base balance. Electrolytes as sodium, potassium, and chloride can dissociate into positively and negatively charged particles capable of conveying electrical impulses. Thus, dissolving sodium chloride, commonly known as table salt, in water separates the electrolyte into sodium (positively charged) and chloride (negatively charged). Positively charged (metallic) elements in the diet often are referred to as minerals. With the exception of phosphate, all of the nutrients cited in this article bear a positive charge.

Alcohol consumption, both chronic and acute, has major effects on the absorption, elimination, and serum concentrations of many physiologically important electrolytes and minerals, including sodium, potassium, phosphorus, calcium, magnesium, iron, zinc, and selenium (Beard et al. 1979; Harris et al. 1979; Arieff and Papadakis 1988; Knochel 1988; and McClain et al. 1986). Electrolyte disturbances may lead to severe and even life-threatening metabolic abnormalities. This article provides a clinical overview of the effects of acute and chronic alcohol intake, as well as of liver disease, on these electrolytes.

ELECTROLYTE ABNORMALITIES

Sodium and Water Balance

A close relationship exists between the metabolism of water and that of sodium. Sodium is the primary electrolyte present in body fluids outside the cells, with only about 5 percent of the sodium concentration of the body occurring intracellularly. This electrolyte, together with potassium, assists in the maintenance of the body's electrolyte and water balance. In addition, potassium and sodium play an important role in nerve conduction, muscle contraction, and the transport of substances across membranes.

Only one-third of the body's water, however, is outside the cells (Levinsky 1987). The presence of water in the body is essential for the performance of many physiological functions. Water helps to equilibrate and maintain body temperature; provides moisture to the surfaces of the lungs; furnishes a medium for digestion, absorption, and metabolism; and acts as a solvent for the other materials in the cell.

Because a close relationship exists between the metabolism of water and sodium, changes in the fluid volume inside vessels and around the cells--fluid that consists mainly of water and sodium salts--may have a major impact on serum sodium concentrations.

Alcohol consumption can have pharmacological effects on water and sodium metabolism. The effects of alcohol on sodium and water balance may differ with acute alcohol intake, chronic alcohol intake, or acute withdrawal from chronic alcohol abuse.

As the blood alcohol level rises with acute alcohol intake, a transitory increase in the elimination of "free water" (water without salts) by the kidney occurs (Rubini et al. 1955), resulting from inhibition of the release of antidiuretic hormone (ADH). As the plasma alcohol level decreases, urinary flow is reduced (Nicholson and Taylor 1938). Concomitant stimulation of water intake (Sargent et al. 1978) causes significant water gain. This water retention occurs together with sodium retention (Nicholson and Taylor 1938;...