Need in salt
Is it salt or sodium?
Salt is composed of 40% sodium (Na) and 60% chloride (Cl) but 90% of the sodium we consume comes from salt.
Did you know that in ancient times salt was very expensive and used as a currency or tax, such as “gabelle” in France.
Why do we need salt?
Sodium is the major extracellular electrolyte and is essential for many functions in our body. Sodium is involved primarily in the regulation of water and mineral balance and acid-base (pH) equilibrium.
Together with chloride (Cl) and potassium (K) , sodium regulates the pressure (osmotic pressure) on both sides of cell membranes. Of those 3 nutrients, mainly sodium concentration changes activate the release of hormones that regulate water equilibrium. Because of this mechanism and some others, sodium plays a key role in the regulation of blood pressure.
It is also very important for muscle and nerve function.
How much do we need?
A minimum of 200-500 mg per day is considered necessary for the function of our body. However, we tend to consume far more than is needed, between 4 and 6 grams per day (10 to 15 g of salt).
Salt is a flavor enhancer and we like salty snacks such as crisps or salted nuts. Salt is also used as a preservative and some processed foods contain high amounts of salt, such as charcuterie, cheeses and bread. Even breakfast cereals contain salt. Because studies have shown that high salt intake is associated with elevated blood pressure (some individuals are more sensitive than others), there are recommendations to limit salt intake in many countries, ranging from 1.5 g to 2.4 g per day.
Based on a recent review of the literature, the World Health Organization (WHO) recommends decreasing sodium intake to less than 2 g per day in adults (5 g of salt).
What are the main sources?
A large part of the sodium we consume comes from hidden salt. The amount depends on the food content but also the quantity of the food we eat and thesalt we add while cooking or eating.
Bread contains 500-600mg of sodium per 100g, therefore a portion of 45g brings already around 250mg sodium. On the other hand, vegetables contain very low amounts of salt and their consumption should be largely encouraged.
Guideline: Sodium intake for adults and children, WHO, Geneva (2012)
Essentials of Human Nutrition, J. Mann and A. S. Truswell Editors. Oxford University Press, 2012