Sodium is an essential element for the body. However, it can cause many harmful effects when consumed in excess or even in too small quantities. Consequences and causes of changes in sodium levels: everything you need to know can be found in this article.
What is sodium?
Sodium is a mineral that the body needs in large amounts to function properly. It is a member of the electrolyte family. Their characteristic is that they carry an electrical charge when dissolved in body fluids such as blood. As a result, the roles of sodium in the body can easily be deduced.
Most sodium is found in the blood and in the fluids around the cells. In the body, sodium is stored in bones and blood plasma.
What is the difference between salt and sodium?
Salt is actually known as sodium chloride, of which sodium is only part of its composition. It is our table salt. There are 400 mg of sodium in 1g of salt.
What is the role of sodium in the body?
The main role of sodium is to regulate the body’s water content and therefore to maintain a normal water balance. It also plays a key role in the transmission of nerve impulses and muscle contraction.
Sodium also plays a role in the intestinal absorption and reabsorption by the kidneys of certain nutrients: chlorine, amino acids (constituents of proteins), glucose and water.
Sodium is also involved in the formation of bone tissue and helps maintain the body’s acid-base balance.
Sodium requirements are covered by the food and beverages ingested. The body draws on this sodium, uses it and then eliminates it, mainly in the form of sweat and urine thanks to the work of the kidneys. When functioning normally, the kidneys are able to maintain a constant level of sodium in the body. This is achieved by varying the amount of sodium excreted in the urine.
When sodium intake and loss are no longer balanced, then the total amount of sodium is affected. In this way, the concentration of sodium in the blood can be too low, this is called hyponatremia, or too high, this is called hypernatremia.
What is hyponatremia?
What are the causes?
As explained earlier in the article, hyponatremia is caused by a low level of sodium in the body relative to the amount of fluid it contains. In this case, the amount of fluid in the body may be unchanged, insufficient or excessive, but in all cases the sodium is diluted.
There are numerous causes of hyponatremia. Vomiting or severe diarrhea are the most common, resulting in a significant loss of sodium. The mistake to make in this case is to compensate for the loss with water only, as the sodium becomes more and more diluted, its level does not increase sufficiently.
Furthermore, kidney disease, cirrhosis and heart failure are also responsible for causing hyponatremia. Indeed, they lead to water and fluid retention in the body. The proportion of fluids then exceeds the sodium, which becomes diluted and too low.
Thiazide diuretics are also a common reason for hyponatremia. These drugs provoke increased sodium excretion, which in turn increases water excretion.
What are the consequences?
The most sensitive organ to changes in blood sodium levels (natremia) is the brain. Therefore, the first symptoms to appear are mental confusion, lethargy or in some cases signs of brain dysfunction.
What is hypernatremia?
What are the causes of hypernatremia?
Conversely, hypernatremia is characterized by a lack of water relative to the amount of sodium in the body. In most cases, this is the result of dehydration, when the loss of water is greater than the loss of sodium.
There are many causes of dehydration: insufficient water intake, taking diuretics, excessive sweating, vomiting or diarrhea.
What are the consequences?
The first symptom to occur is usually thirst. In the most severe cases, hypernatremia leads to cerebral dysfunction. Symptoms are numerous: confusion, convulsions, cramps, coma. Severe hypernatremia can even cause death.
What is the recommended daily sodium intake?
AFFSA’s recommendations set an intake of 6 to 8 grams of salt per day, or 2400 to 3200 mg of sodium per person per day. It should be noted that the average consumption in France is around 12 g of salt and therefore far exceeds the official recommendation. As we have seen, too low sodium intakes are bad for your health, but so are excessive intakes. Accordingly, excessive sodium intakes are a risk factor for high blood pressure. It is therefore essential to find the right balance.
What foods contain sodium?
Sodium is naturally present in foods, but in small amounts. Most of the sodium consumed is found in table salt but also in salt added by industrialists in their food preparations.
As a result, many foods are affected:
- delicatessen products,
- ready meals,
- canned food,
- some biscuits,
Foods low in salt are therefore to be favoured:
- fruits and vegetables,
- pulses (lentils, beans, chickpeas),
- oleaginous fruits (walnuts, almonds, hazelnuts).
Does sodium make you gain weight?
The answer is no, sodium is not involved in the weight gain mechanism. On the other hand, an excess of sodium consumption can lead to the creation of water retention and thus cause a change in body mass.
What is the sodium requirement for athletes?
Athletes eliminate more sodium from the body, especially through sweat. As a result, their sodium requirements are increased. It is therefore important for athletes to stay well hydrated throughout the day and during physical exercise. Also, do not hesitate to choose your food from the list of foods to favour, cook them yourself and add a little salt directly to your plate.
When your effort lasts more than 1h30min, it is important to compensate for the loss of electrolytes and especially sodium. To do this, add 1g of salt to your exercise drink (per 1L). The salt is not felt because the quantity is too small. It is also important to add a source of carbohydrates: grape juice, sugar, pineapple juice, etc. This prevents fatigue during exercise by preventing the body from draining its energy reserves.
Article written by Romane, dietician at Foodvisor.