IS SALT THE ENEMY?

Dr. Enrica Falbo
Nephrology Clinic in Dubai

Sodium Chloride or Kitchen Salt has played a leading role for millennia since Neolithic that is 10.000 years ago, with the appearance of the first stable civilizations that began to feel the need to protect and preserve food for a long period of time; salt in fact, was used, initially as a method of preserving over time meat and fish. Important indications on the use of salt already exist in the Sumerian, Egyptian and Roman civilizations.

In Roman times, the use and demand for salt sales increased to the point that it represented not only a coveted bargaining chip, but also an instrument of power; the Romans called the Salt the ’White Gold”. Salt is also part of myths and religions where this element has always been considered a source of power.

The Egyptians used salt in the mummification process, the Maya as medicine and it was used during sacrifices by the Greek and Romans. In the Jewish religion salt is a symbol of brotherhood while it recurs in the Old Testament in numerous parables of Christ, with the meaning of wisdom incorruptibility and covenant. In India the gift of salt is symbol of good luck and a reference to Mahatma Gandhi’s liberation of India, which included a symbolic seaside walk to collect tax-free salt the poor.

The history of salt is, therefore, rich in social economic relations and confluences between religious and legendary systems, however it has been viewed with suspicion in the last 40 years, in Western societies whose use has increased until to excess. It is shown that our current salt intake is the main factor in increasing blood pressure and, therefore, a major cause of cardiovascular and kidney disease worldwide; there is a significant association between the urinary excretion of salt in the 24 hours, index of the daily salt consumption, and the blood pressure levels the systolic one.

Some countries like Japan, UK, Finland have reduced the amount of salt consumed, involving the food industry to reduce the amount of salt added to foods, by labelling the salt content on food packaging clearly. They have also raised public awareness of the harmful effects of salt on health; many other countries such as Australia, Canada and the United States are also doing the same. In developing countries, about 85% of the global disease burden is related to the increase in blood pressure, most of the salt consumed comes from the salt added during cooking or from sauces; therefore, it would be important to educate from childhood in schools to reduce salt intake, with economic benefits in all countries of the world.

The World Health Organization (WHO) estimates that 62% of all strokes and 49% of coronary events are secondary to hypertension. The scientific evidence accumulated to date suggests that modest reductions in dietary salt (from the current intake of 9-12 g / day to the recommended level of less than 5-6 g / day) will have beneficial effects on cardiovascular health along with significant savings on health care costs, reducing the incidence of deaths from stroke and heart attack by at least 7%.

A diet rich in salt, on the other hand, can have direct harmful effects regardless of its effects on blood pressure, for example by increasing the risk of kidney disease, stroke, left ventricular hypertrophy, because left ventricular mass is closely related to salt intake, and it induces renal hyperfiltration and increases glomerular pressure. Salt induces damage to the heart and kidney even independently of the increase in blood pressure which it also determines it has a role in the pathogenesis of autoimmune diseases, in fact even the increase of the latter, in Western countries, has been more recently correlated with the increased consumption of salt.

The pathogenesis of autoimmune diseases is multifactorial, with a combination of genetic and environmental factors involved, including diet, increased salt consumption, excess salt in processed foods exacerbates proinflammatory responses that influence the pathogenesis of those diseases, including multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus and Crohn's disease, etc ; this pro-inflammatory role of salt is demonstrated even if the mechanisms that mediate the activation of the immune system are not yet clear. Growing evidence also suggests that salt intake is related to obesity, and it is also associated with kidney stones and osteoporosis and is probably a leading cause of stomach cancer, found in countries historically considered large consumers of salt like Japan. Underrated aspects of salt include its ability to increase anxiety, and, through non-osmotic mechanisms, it also contributes to local tissue inflammation. The World Health Organization sees reducing dietary salt intake as a global emergency to combat the high mortality and high costs of cardiovascular disease.