Sodium accumulation in the brain may be one of the causes of hypertension

The world is far from reaching the global goal of reducing sodium intake by 30% by 2025. The data comes from an unprecedented report by the World Health Organization (WHO) on the consumption salt.

Although it is an essential nutrient, sodium, when ingested in excess, increases the risk of heart diseases such as stroke, high blood pressure and premature death. The main source of sodium is table salt (sodium chloride), but other seasonings, such as sodium glutamate, also contain sodium.

The WHO report reveals that only 5% of countries have mandatory and comprehensive sodium reduction policies and 73% do not fully implement these policies.

The association between salt and blood pressure has been studied for more than a century. However, there are few answers to the association between high salt intake and changes in the central nervous system (CNS), which contribute to what is called neurogenic hypertension.

Researchers at the University of São Paulo (USP) have made progress in understanding this process. Studies have revealed that some of the salt consumed in excess is retained in the cerebrospinal fluid – called cerebrospinal fluid. The results suggest a possible mechanism that triggers the disease that involves the activation of not only neurons, but also other glial cells, another type of cell found in the nervous system.

The research paves the way to understanding the mechanisms and connections between neural cells involved in the formation of hypertension associated with high salt intake. The results have been published in the scientific journals Molecular and Cellular Neuroscience and Experimental Physiology.

understand the process

Previous studies have already shown the involvement of the hypothalamus, a region of the brain, in the development of high salt-dependent hypertension. The neural cells of this nucleus, mainly neurons, participate directly and indirectly in the regulation of blood pressure in response to an increase in sodium circulating in the body.

The researchers then sought to study the involvement of neural glial cells in this process. Experts noted that astrocytes, which are one of the most abundant cells in the central nervous system, were more activated in the brains of animals exposed to high salt intake.

“In general, astrocytes are cells that, in addition to supporting neurons, are also responsible for the release of several neurotransmitters, including ATP. [trifosfato de adenosina], a molecule that has always been known for its role in cellular energy metabolism, but which also acts as a neurotransmitter. Faced with a condition of high salt consumption, the astrocytes are intensely activated”, explains Renato Willian Martins de Sá, doctor at LCNC, scholarship holder of the São Paulo State Research Support Foundation (Fapesp).

Studies indicate that the accumulation of sodium in the cerebrospinal fluid may be linked to the development of diseases not only of the cardiovascular system, but also of neurodegenerative diseases, including Alzheimer’s disease, since an excess of salt in the brain can alter the functions of neural cells, from its genetic and protein machinery to neurochemistry.

“Understanding these mechanisms can help in the development of new pharmacological therapeutic strategies for diseases associated with high salt consumption”, explains Professor Vagner Roberto Antunes, coordinator of the laboratory, in a press release.

Changes can save lives

The WHO recommends that daily salt intake not exceed 5 grams, with the aim of reducing hypertension and other cardiovascular diseases.

Implementing highly cost-effective sodium reduction policies could save an estimated 7 million lives worldwide by 2030. This is an important part of action to achieve the Sustainable Development Goal of reducing deaths from non-communicable diseases.

Currently, only nine countries (Brazil, Chile, Czech Republic, Lithuania, Malaysia, Mexico, Saudi Arabia, Spain, Uruguay) have a comprehensive set of recommended policies to reduce sodium intake.

“Unhealthy diets are among the leading causes of illness and death worldwide and excessive sodium intake is a major culprit,” said Tedros Adhanom, Director General of WHO.

“This report shows that most countries have yet to adopt mandatory sodium reduction policies, leaving their populations at risk for heart attack, stroke and other health problems. The WHO is calling on all countries to implement ‘best investments’ to reduce sodium and manufacturers to implement the WHO benchmarks for sodium content in foods,” he adds. .

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