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Sodium regulates the body’s fluid balance

The main function of sodium is to regulate the body’s fluid balance.


  • Sodium regulates the body’s fluid balance.
  • Many foods naturally contain sodium and that amount would be enough to meet an adult’s essential sodium needs.
  • Excessive blood sodium levels can disrupt many vital functions.


Sodium is mainly obtained from food in the form of table salt or foods that naturally contain salt. However, dietary sodium has little effect on blood sodium levels as the kidneys remove excess salt. 

Sodium is one of the most important salts in the body. It is essential for life, being a key substance in maintaining the membrane tension of all cells. Excessive blood sodium levels can disrupt many vital functions.

Sources of sodium in the diet 

Sodium in salt is a prerequisite for the normal functioning of the body. While we need salt every day, excessive use is not recommended. 

Many foods naturally contain sodium and that amount would be enough to meet an adult’s essential sodium needs. Cow’s milk, meat, and eggs, for example, are excellent natural sources of sodium. 

Most common sources of salt in the Swedish diet are bread and other cereal products, meat products, cheese, spice mixtures and sauces, and processed snacks. These foods contain hidden salt that is industrially processed, which means that it lacks the minerals and micronutrients obtained from natural salt. 

Natural salts are the most favourable source of salt for the body as they contain minerals and micronutrients important for the body, such as potassium, calcium, magnesium, and iron. 

What is the recommended sodium intake? 

Recommended salt intake for adults is no more than 6 grammes per day which equals to about one teaspoon. 

Reference values for sodium

Reference levels may vary depending on the laboratory and the test analysis method.

Low sodium level (hyponatremia)

There are basically two causes of low sodium levels (hyponatremia): either too much sodium is lost or too much water accumulates in the body.

Typically, low blood sodium levels are the result of heavy physical exercise-induced sweating. Fluid and salts are lost along with sweat, creating an imbalance in the body’s fluid and salt balance.

Mild hyponatraemia is common in patients with congestive heart failure and should not be treated with additional salt or saline tablets. This can lead to swelling and worsening symptoms of heart failure. Loss of sodium caused, for example, by prolonged vomiting or diarrhoea is also a common reason for low sodium values. 

Low sodium levels are linked to cardiac arrhythmia and weakness. Very low levels (less than 120 mmol/L) can lead to convulsions and impaired consciousness. 

High sodium level

Compared to low sodium levels, elevated sodium levels (hypernatremia) are much less common. In fact, elevated levels can only happen when, for some reason, the body is not able to replace the water lost.

A rare disease of the pituitary region blocks the production of the water hormone, as a result of which the patient may urinate more than ten litres a day. The patient is unable to drink enough liquids to replace the water lost in urine, which is why the sodium value increases. Excessive blood sodium levels can disrupt many vital functions.


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