Salt - White Death or Essential Element?

Sodium is mainly found in table salt. It is an essential nutrient required to maintain plasma volume, acid-base balance, transmission of nerve impulses, and normal cell function [1, 7]. Sodium performs many physiological functions, including the absorption of nutrients and the maintenance of fluid balance - osmolarity.

Salt and public health

Studies on the general population find that sodium excess is strongly associated with certain health risks, such as high blood pressure – hypertension [3, 4, 5]. For this reason, WHO has established recommendations for daily consumption of no more than 2.3 g of sodium or 5 g of salt (table salt is 40% sodium) [1]. Indeed, most people with a sedentary lifestyle consume as much as 9-12 g of salt per day from processed foods. For example, one Big Mac contains 2.3 g of salt [9], and 4 slices of bacon contain 1.7 g [10]. Such people may benefit from reducing their salt intake, especially if they are elderly and have hypertension, any other diseases associated with kidneys (e.g. renal dysfunction) or blood vessels (e.g. cardiovascular disease; CVD).

In addition, the trends indicate that people consume less vegetables and fruits, which leads to potassium deficiency [1]. This increases the fluid imbalance between the intra- and extra-cellular environment, because sodium and potassium play a major role in this process [13]. Therefore, reducing salt intake is the most cost-effective and effective method for combating hypertension and can save 2.5 million lives annually [1] (for a detailed analysis of the diet for lowering blood pressure, the reader is referred to the DASH diet [6])

The need for salt in sports

While such recommendations apply to the general population, they are not suitable for healthy active people, and especially athletes.

An athlete can expend about 1.3 g of salt with sweat for every pound (0.45 kg) lost during high-intensity exercise [8] or 2.5 g of salt per hour; however, the exact amount of sweat and sodium lost during activity varies greatly between individuals and can also depend on the type of activity, air temperature, altitude and individuals’ thermal regulation.

However, athletes should consume more sodium/salt than the WHO recommends because sodium deficiency can lead to chronic fatigue, heart failure due to low plasma levels, seizures, dehydration, as well as epilepsy and death [7].

Salt = harm. Myth or truth?

The expression "Everything in moderation" is perfect here. Salt is critical for the body, but its excess can lead to problems in some cases.

The exact recommended amount depends on the level of activity and diet and genetics. Some people who sweat a lot lose sodium through sweat faster than others. It is not worth taking separate measurements of sodium loss unless you are a professional athlete (but you can read about measurement methods here [12].

Also, there are people who react to sodium consumption differently, where one will immediately have an increase in blood pressure (responders), and the other will not have such an effect (non-responders) [11].

How much salt should I consume?

Therefore, if you are not hypertensive, your blood pressure does not fluctuate, and you regularly engage in physical activity, then your salt consumption should be from 5g and above. Pay attention to the symptoms of sodium deficiency and excess, described above.

On the contrary, if there are predispositions such as hypertension, CVD, and you are elderly, then salt intake should be < 5g or < 2.3g sodium per day, and perhaps even lower – 1.5g sodium/day [7]. Such individuals are advised to consult a specialist and follow the DASH diet.