Consistent consumption of salty foods disrupts the balance of gut bacteria, initiates inflammatory responses in the brain, impairs memory, and provokes anxiety. This is the conclusion reached by Chinese scientists in a study published in the EJP journal.
While the body requires salt, excess amounts frequently lead to elevated blood pressure and increased risks of cardiovascular diseases. The WHO advises limiting intake to no more than 5 grams of salt daily, yet most individuals actually consume double this recommended limit. Recent research suggests that the detrimental effects also extend to the brain.
A team from the Medical Research Center at Xi’an Jiaotong University investigated how an excessive salt intake impacts the “gut-brain axis”—the network of biochemical signals linking the digestive and central nervous systems.
The experiment involved six-month-old male mice. Subjects were split into two cohorts: one received a standard diet, while the other was fed rations containing a very high concentration of salt (8% sodium chloride). After half a year, the rodents on the “salty” menu exhibited significantly raised arterial pressure, heightened anxiety levels, and poorer memory function.
In behavioral assessments, the mice in the second group tended to avoid open areas and struggled more to recognize novel objects. Experts observed a reduced density of neurons in their hippocampus, the region responsible for learning and memory formation.
The researchers also successfully identified changes in gene activity. In the hippocampus, the expression of inflammatory genes increased, conversely, genes associated with cell survival were suppressed. This pattern points toward the development of neuroinflammation.
Concurrently, the study’s authors analyzed the composition of the gut microbiome. The high-salt diet drastically altered the bacterial profile: the proportion of certain pathogens grew, while beneficial bacteria diminished. These shifts correlated logically with the inflammatory processes observed in the brain.
In the authors’ view, excess salt causes a restructuring of the intestinal microbiome, and the byproducts of bacterial life, along with immune signals, impact the brain, modifying gene function and contributing to neuron death.
Moving forward, the team plans to conduct experiments involving microbiota transplantation and to investigate the effects of salt on the brains of female subjects and other areas of the nervous system. This future work aims to aid in developing new strategies for preventing cognitive decline through modifications to diet and the microbiome.
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