What are electrolytes in the body?
Electrolytes are substances that contain positively or negatively charged particles (ions) of different chemical elements: one example is sodium chloride (NaCl) from the positively charged sodium ion (Na +) and the negatively charged chloride ion (Cl-).
Mineral substances are subdivided into so-called quantity elements and trace elements – depending on whether the respective mineral is necessary in larger quantities or only in small traces.
The three following ions of different electrolytes form the main part of the total mineral content of the human body:
Electrolytes have numerous functions: they play an important role in maintaining the water balance and are involved in the electrical activity of the muscle and nerve cells.
Each electrolyte ion is distributed differently in the body:
- Some electrolyte ions deposit predominantly in the cells (intracellular)
- Others circulate mainly in the bloodstream. These are outside of the cells (extracellularly).
The human body absorbs electrolytes mainly via beverages and with food and human body excretes them mostly through the kidneys, but also through the digestive system and the skin.
If the body absorbs or precipitates too much electrolytes, an electrolyte fault (in the form of an electrolyte deficiency or electrolyte excess) occurs: If the electrolyte balance of the body is disturbed, it has become unbalanced.
Distribution disturbances between the electrolytes located inside and outside the cells also lead to a changed electrolyte concentration – with pathological consequences.
Electrolyte disorders have different effects depending on the different functions of the electrolytes: they can range from an overflow due to confusion due to changes in nervous activity to cardiac arrhythmias and coma.
Often the symptoms do not clearly indicate electrolyte changes. Therefore, the disorder can often only be determined by determining the electrolytes in a blood test – possibly also by an electrocardiogram (ECG).
Electrolytes in the body- Sodium
The individual electrolytes are distributed differently in the body. The sodium chloride from sodium (Na +) and chloride (Cl-) forms the most important component outside the cells.
Sodium is the most frequently charged positively ion (so-called cation) in the blood plasma. The electrolyte ion reaches the body to a large extent in the form of saline via the food. Since sodium is contained practically in all foods, a sufficient intake is ensured. The body usually excretes sodium from the kidneys under normal circumstances.
The sodium content in the blood influences how much fluid circulates in the body’s circulation. If the body can not excrete sodium sufficiently (for example because of kidney disease), the electrolyte ion also accumulates water in the body. Normally, a sophisticated control system ensures a constant sodium level.
Doctors often use urine or blood tests to determine sodium as a routine without any special suspicion. A changed sodium value indicates a disturbed water balance, especially in:
- Diseases of the heart
- Kidney disease
Possible causes for elevated sodium levels (hypernatremia) are:
- High saline feed with food
- Diarrhea, vomiting
- Lack of liquid supply
- Diabetes insipidus
- Derailed diabetes mellitus
Possible causes of low sodium levels (hyponatremia) are:
- Low sodium intake
- Diarrhea, vomiting
- Heart failure
- Renal failure with high water intake
- Adrenal cortex function (Addison’s disease)
- Medicines (including certain diuretics, antidiabetics, antidepressants, cytostatics)
Electrolytes in the body- Chloride
The electrolyte-ion chloride (Cl-) is a negatively charged particle (so-called anion), which together with sodium (Na +) forms sodium chloride.
Man largely absorbs chloride-containing electrolytes through the food and excretes them mainly through the kidneys.
The concentration of chloride in the blood is checked together with the determination of the sodium values. If the regulation of the saline content in the body is disturbed, the values of both minerals are often changed.
The electrolyte determination is particularly important in the case of a disturbed acid-base balance of the blood: Various diseases – for example prolonged vomiting. The determination of the concentration of chloride helps to detect the cause of such disturbances.
Possible causes for elevated chloride values are:
- Disorders of sodium
- Acid-base disorders
- increased chloride supply
Possible causes for low chloride values are:
- Loss of gastric juice by vomiting
- Medicines (certain diuretics that specifically cause an increased excretion of chloride)
- Acid-base disorders
Electrolytes in the body- Potassium (K +)
The electrolyte ion potassium (K +) is a positively charged particle (a so-called cation). Potassium is found in the human body mainly within the cells (intracellularly) and only at a small fraction In the bloodstream outside the cells.
Therefore, causes for a disturbed potassium concentration in the blood are often distortion disturbances between the cells and the extracellular space. But kidney damage also causes a disturbance of the amount of potassium in the blood.
Potassium-containing electrolytes are found in numerous nutrients: especially foods such as fresh vegetables and fruit contain a lot of potassium. The body excrets this mineral primarily through the kidneys, to a small extent also over the intestine or the skin (by sweating).
Potassium is important for the electrical function of all body cells. Muscle and nerve cells in particular depend on a normal potassium value. The effect of the electrolyte ion is particularly evident in the heart muscle in this case.
Serious disturbances in the potassium balance are often also independent of the laboratory values in the electrocardiogram (ECG) and can lead to life-threatening functional disorders of the heart.
The most frequent potassium deficiency is hypokalemia. A deficiency of potassium usually results from losses through the kidneys or the digestive system. An increased potassium value may be falsely produced if a red blood cell solution dissolves in the blood sample (hemolysis).
Possible causes of elevated potassium values are:
Increased potassium intake
Chronic or acute renal failure
Adrenal cortex function (Addison’s disease)
Drugs (e.g., certain diuretics that cause less potassium precipitation than others, or ACE inhibitors or cytostatics)
Severe cell breakdown
Possible causes of low potassium levels are:
- Potassium loss through the kidney
- Potassium losses via the gastrointestinal tract (by vomiting, diarrhea, laxative abuse)
- Potassium movement from the blood circulation into the cells (for example, in the case of metabolic or respiratory alkalosis caused by metabolism or respiration
Electrolytes in the body- Calcium (Ca2 +)
One of the most important electrolyte ions in the human body is calcium (Ca2 +), which is the main component of the bones and teeth in the form of hydroxyapatite.
Altogether about 1000 grams of bound calcium are present in the human body. Only a fraction (less than 1%) of the calcium circulates as a positively charged electrolyte ion (cation) in the blood circulation and assumes numerous functions.
The human body absorbs calcium-containing electrolytes – as well as sodium, chloride and potassium – through the food and separates the calcium mainly from the kidneys. However, the body can also incorporate excess calcium into the bone, which is a kind of calcium requirement memory.
Several hormones are involved in the maintenance of the calcium concentration in the blood: they regulate both the uptake and storage or the release of calcium from the bone as well as its excretion via the kidneys.
In addition to its function in bone formation, calcium plays a role in muscle contraction, blood coagulation, the release of hormones and the activity control of enzymes (= compounds that regulate metabolism).
In addition, this electrolyte ion influences the permeability of the cell membranes. A deficiency of calcium favors convulsions, while a greatly elevated calcium level can cause serious symptoms such as cardiac arrhythmia or disturbances of brain activity.
Calcium is one of the electrolyte ions, which are mainly present outside the cells. Here, calcium is bound to proteins (albumin) in the blood. Therefore, protein deficiency can cause a disorder of the calcium level.
Electrolytes in the body- Phosphate
Phosphate-containing electrolytes also play an important role in the human body. Phosphate is a mineral that is mostly bound in the human body in the bone and teeth.
The concentration of phosphate in the blood – like that of calcium – is subject to strict regulation by hormones. If the calcium level is disturbed, the phosphate value is usually outside of its normal range.
For the excretion of phosphate is mainly the kidney, but instestine is more responsible.
Possible causes for elevated phosphate values are:
- Kidney failure, dialysis
- Vitamin D poisoning
- Increased phosphat
- Physical exertion
Possible causes for low phosphate values are:
- Vitamin D deficiency
- Phosphate losses via the gastrointestinal tract (in case of vomiting, diarrhea, laxative abuse)
- Unilateral diet (by alcoholism or fasting)
- Acidification (acidosis)
- Parathyroid gland hyperfunction (hyperparathyroidism)
- Certain hereditary renal diseases (tubular resorption disorders)
Electrolytes in the body- Magnesium (Mg2 +)
Magnesium-containing electrolytes are also important for the human body: magnesium (Mg2 +) is – similar to calcium – a mineral necessary for muscle function. In addition, many enzymes (compounds that regulate metabolism) in the body require magnesium.
There is a close connection between the concentration of magnesium and calcium in the body: the concentrations of these two electrolyte ions usually rise or fall. The symptoms in the case of disturbances of the magnesium and calcium are also similar.
Possible causes of increased magnesium are:
- Severe kidney failure
Possible causes for low magnesium levels are:
- Unilateral diet (by alcoholism or fasting)
- Magnesium loss over the gastrointestinal tract (vomiting, diarrhea, laxative abuse)
- Increased need (during pregnancy)
- Increased excretion via the kidneys (by drugs: diuretics)
- Acute pancreatitis
- Diabetes mellitus or insulin therapy