Well over half of our body weight is water. Doctors believe that the body's water is restricted to different spaces, called fluid compartments. The three main compartments are
-Liquids contained in the cells
-Fluids in the space surrounding the cells
- Blood
In order to function normally, the body must prevent the fluid levels in these areas from varying too much.
Some minerals, particularly the macrominerals (minerals that the body needs in relatively large quantities), are important as electrolytes. Electrolytes are minerals that carry an electrical charge when dissolved in a liquid such as blood. Blood electrolytes (sodium, potassium, chlorine and bicarbonate) help regulate nerve and muscle function and maintain acid-base and water balance.
Electrolytes, particularly sodium, help the body maintain normal fluid volumes in fluid compartments, as the amount of fluid in a compartment depends on the amount (concentration) of electrolytes present. If the electrolyte concentration is high, fluid enters that compartment (a process called osmosis). Similarly, if the concentration of electrolytes is low, the fluid leaves that compartment. To adjust fluid volumes, the body can move electrolytes in and out of cells. Thus, it is important to have adequate electrolyte concentrations (electrolyte balance) to maintain water balance in the compartments.
The kidneys help to maintain electrolyte concentrations by filtering electrolytes and water from the blood, returning some of them to the blood and excreting the excess amount in the urine. In this way, the kidneys help maintain the balance between daily electrolyte and water intake and excretion.
If the electrolyte balance is altered, disorders may occur. For example, an electrolyte imbalance may be due to
- Dehydration or overhydration
- Taking certain medications
- Certain heart, kidney or liver disorders
-Too much fluid or food given intravenously or orally