Sodium is a mineral that plays an important role in the hydration status of the body.

It is found in the blood and in the extracellular fluid that bathes the cells.

Sodium also helps maintain acid-base balance and is essential for the transmission of nerve impulses and muscle contraction.

In excess, however, it can be harmful.

This is why current recommendations aim to limit sodium intake.

Sodium characteristics

• Mineral with a very important role in the distribution of water in the body
• Influences blood pressure, nerve impulse transmission and muscle contraction
• Found in large amounts in table salt, smoked and pickled products
• Sodium intake should be limited
• Excess sodium can be dangerous for arterial and renal health

Benefits and functions of sodium in the body

Water balance

The concentration of sodium in the body regulates the movement of water between the different intracellular and extracellular compartments.

Through the phenomena of homeostasis and absorption, the right amount of sodium is responsible for the body's water balance.

Nerve impulses

The presence of sodium in the body enables the transmission of nerve impulses to the neurons in the brain through polarisation phenomena.

Muscle contraction

Sufficient sodium also enables the muscle contraction mechanism.

Blood pressure

Sodium is also involved in the regulation of blood pressure.

A high sodium intake significantly increases blood pressure and vice versa.

This is why people with high blood pressure are often advised to eat a diet that is more or less free of salt.

What is the difference between sodium chloride, salt and sodium?

Salt is made up of chlorine and sodium, which is why it is also called sodium chloride.

Sodium is just one of the two compounds in salt.

1g of salt contains 400mg of sodium and 600mg of chlorine.

On the other hand, you need 2.5g of salt to get 1g of sodium.

20 foods high in sodium

The main sources are prepared and packaged foods.

In fact, more than 75 per cent of the sodium we eat comes from processed foods such as cheese, sausages, pizza, sauces and soups, as well as dried or smoked foods.

Foods, portions and sodium content

• Miso, fermented products, 175ml (3/4 cup) = 7583mg
• Dried meat, 100g = 2790mg
• Table salt, 1 tsp = 2373mg
• Grilled bacon, 100g - 4 slices = 2310mg
• Regular ham, 11% fat, sliced, 100g = 1500mg
• Ready to serve fish sauce, 15ml = 1408mg
• Baking powder, 1 teaspoon = 1284mg
• Soy sauce, shoyu and tamari, 15ml = 914-1038mg
• Canned pulses, 1 cup = 718-873mg
• Marinated Atlantic herring, 100g = 870mg
• Smoked salmon, 100g = 784mg
• Ready to serve teriyaki sauce, 15ml = 700mg
• Tinned tomato sauce, 125ml = 678mg
• Low sodium soy sauce, 15ml = 608mg
• Tinned anchovies, 4 anchovies (16g) = 588mg
• Dill gherkin, 1 gherkin (65g) = 569mg
• Feta cheese, 50g = 558mg
• Tinned sardines, 100g (8 medium) = 505mg
• Sauerkraut, tinned, 1/2 cup = 496mg
• Cottage cheese, 2% fat, 125ml (1/2 cup) = 485mg

How to use sodium correctly?

Sodium use

Current recommendations aim to limit salt intake from food.

Men should not consume more than 8g of salt per day, while women and children should limit their intake to 6.5g of salt per day.

For sodium, there are recommendations for adequate intake (AI) and maximum tolerable intake (AMT).

Adequate Intake (AI), Maximum Tolerable Intake (AMT)

• Infants 0-6 months 120 mg
• Infants 7-12 months 370 mg
• Infants from 1 to 3 years 1000mg, 1500mg
• Children from 4 to 8 years 1200mg, 1900mg
• Children from 9 to 13 years 1500mg, 2200mg
• Children from 14 to 18 years: 1500mg, 2300mg
• Men aged 19 to 50: 1500mg, 2300mg
• Women 19 to 50 years old: 1500mg, 2300mg
• Men 50 years and older: 1300mg, 1200mg, if 70 years or older, 2300mg
• Women 50 years and older: 1300mg and 1200mg, 2300mg if 70 years or older
• Pregnant women: 1500mg, 2300mg
• Women who are breastfeeding: 1500mg, 2300mg

Carbonate, sodium bicarbonate, sodium citrate and other forms in food

Although sodium chloride is the main source of sodium in the diet, other forms are often found as additives in foods (monosodium glutamate, sodium benzoate, sodium nitrite, disodium pyrophosphate, etc.).

Sodium bicarbonate and sodium citrate are found in many antacid-type medicines.

Adverse effects of sodium

Consequences of sodium deficiency

Sodium deficiency is very rare.

Even when dietary sodium intake is low, the body usually adjusts by reducing losses through urine and sweat.

On the other hand, a deficiency can occur with repeated vomiting, prolonged diarrhoea or excessive sweating.

Too little sodium can lead to some harmful side effects.

Symptoms of sodium deficiency include muscle cramps, loss of appetite, dehydration, low blood pressure and confusion.

Too much sodium

On the other hand, excessive sodium intake, which is much more common, can also lead to adverse effects, including high blood pressure and loss of bone mass (osteoporosis).

High blood pressure is a major risk factor for stroke, heart disease and kidney disease.

The general population consumes far more sodium than it needs.

In fact, the Portuguese average sodium intake in the form of salt is between 2,000 and 4,800 mg per day.

People with high blood pressure, diabetes or chronic kidney disease and the elderly are more likely than the rest of the population to experience an increase in blood pressure after a high sodium intake because they are more sensitive to salt.

Interactions (with other nutrients)

A high intake of potassium would increase the excretion of sodium in the urine and thus reduce the increase in blood pressure caused by excessive sodium intake.

Chemical properties

The symbol for sodium is Na and its atomic number is 11.

Its atomic weight is 22.98976928 u.

It is a naturally occurring, soft, silvery alkali metal.

Sodium is essential in the body and is found at many levels, often in combination with potassium.

In the right amount, it helps maintain homeostasis, water distribution, blood pressure, nervous system function and muscle contraction.

Sodium hydroxide, also known as caustic soda, is the solid form of sodium.

Its chemical formula is NaOH.

It is commonly used to make soaps, washing powders and other relatively aggressive detergents.