Chloride as a nutrient and laboratory value

Chloride is one of the most important electrolytes in the human body. Food contains chloride mainly in combination with  sodium  in the form of table salt or table salt, the so-called sodium chloride. Because of this, many processed foods tend to be high in chloride. How does chloride work in the body, what is chloride and how can you tell if the chloride levels in blood and urine are too high or too low?

What is chloride?

Chloride is a chemical compound of the element chlorine. In the body, it occurs as a negatively charged ion (electrolyte) in so-called extracellular fluids. These are body fluids that are outside of the cells, such as blood plasma or lymph fluid. Chloride is mostly ingested through food in conjunction with sodium. This compound is sodium chloride, i.e. table or cooking salt.

What is the function of chloride in the body?

Chloride plays an important role in regulating the water balance in the body. Together with other electrolytes, it also contributes to the generation of electrical voltage between the inside and outside of the cell due to its negative charge. This allows nerve and muscle signals to be transmitted between the various body cells.

Chloride is also important for the smooth running of digestion and the defense against pathogens, as it forms a component of gastric juice. Chloride is excreted through the kidneys.

chloride in food

Chloride is found in food mainly in the form of sodium chloride. This is ordinary table salt. The more  salt  there is in food, the higher the chloride content.

Foods with little or no chloride are, for example:

• vegetables
• fruit
• (unsalted)  nuts
• cream cheese
• Emmental
• Natural yoghurt

Industrially processed foods in particular have a high chloride content. These include, for example, sausage and baked goods or certain types of cheese, such as feta cheese, and pickled vegetables.

Daily requirement: How much chloride does the body need?

It is not known exactly how much chloride one should ingest per day. It is estimated that every adult over the age of 25 should consume around 2,300 milligrams or 2.3 grams of chloride every day. These guidelines also apply to pregnant and breastfeeding women.

As a rule, the daily intake of chloride is higher because some foods contain a relatively large amount of salt. Under normal circumstances, however, the body can regulate these excessive levels by excreting chloride through the kidneys.

What chloride levels are normal?

Chloride is measured in blood or urine. As a rule, the measurement is carried out to determine the acid-base balance in the body. The specification is given in millimoles per liter (mmol/l).

The following  blood values  ​​for chloride are within the normal range:

• Children up to and including 12 years: 95 to 112 mmol/l
• Adolescents from 13 years and adults: 96 to 110 mmol/l

The normal value for the  24-hour urine collection should be between 100 and 250 mmol/l   for people aged 18  and over .

Chloride deficiency: symptoms and causes

If the chloride levels in the blood are too low, it is called  hypochloremia. This occurs when there is a general loss of electrolytes in the body, for example when more electrolytes are released via the gastric juice, stool, urine or kidneys.
Possible causes of too low chloride values ​​are:

• Vomit
• Diarrhea
• Benign growths in the large intestine (colon adenoma)
• Kidney dysfunction
• Schwartz-Bartter-Syndrom
• Taking diuretics (water medication)

If there is only a slight chloride deficiency, there are usually no symptoms. Severely reduced values ​​can lead to  nausea  and exhaustion. In addition, a lack of chloride can lead to an increase in the pH value of the blood. If the value is above 7.45, one speaks of a  metabolic alkalosis.  This can  trigger cardiac arrhythmias  and neuromuscular hyperactivity – i.e. excessive activity of the muscles and nerves – which manifests itself, for example, in muscle pain, functional disorders or sensory disturbances.

Severe chloride deficiency is treated by administering electrolyte solutions intravenously. If the values ​​are slightly reduced, the intake of salty foods is often sufficient. In addition, the underlying cause should be medically clarified and treated.

Overdose – too much chloride in the blood

If too much chloride is detected in the blood, this is called hyperchloremia. Hyperchloremia can result from disturbances in the acid-base balance. This can lead to  acidosis in  the blood (acidosis). To compensate for this hyperacidity, the excretion of chloride by the kidneys is reduced, which in turn results in increased chloride levels.

Often, the disturbed acid-base balance is related to a loss of bicarbonate, which is involved in maintaining the pH in the body. Even then, the body tries to compensate for the low bicarbonate levels by reducing the excretion of chloride.
The following causes can favor an excess of chloride:

• diseases of the kidneys
• diarrhea (with loss of bicarbonate)
• Renal tubular acidosis (disorder of acid excretion via the kidneys)
• Infusions with sodium chloride
• Taking carbonic anhydrase inhibitors (medicines used to treat glaucoma or  epilepsy )

In addition, too high a chloride value can be caused by diabetic  ketoacidosis  . This is a complication of  diabetes  mellitus that should be treated immediately in intensive care. Typical symptoms of diabetic ketoacidosis include deep breathing (Kussmaul breathing),  stomach pain ,  drowsiness  or the smell of acetone in the breath.

Because chloride levels are closely linked to sodium levels and are regulated by the same system, changes in chloride levels can also be associated with, or caused by, changes in sodium levels.

In the case of elevated chloride values, the causes should be clarified by a doctor and the excess should be treated accordingly. It is also often advisable to avoid products with a high salt content in your diet.