We all know that high salt diet can lead to high blood pressure, and a study published in Science Translational Medicine on March 25 suggests that high salt diet may also weaken the immune system.
The researchers found that mice fed a high salt diet had much more severe bacterial infections. Similarly, volunteers who ate an extra six grams of salt (almost two fast meals) a day also developed significant immune deficiencies.
The latest guidelines for the prevention of cardiovascular and metabolic diseases in China’s healthy lifestyle suggest that adults eat up to 5g of salt a day (no more than a beer bottle cap and a flat cap). In fact, both men and women had significantly higher salt intake.
Previous studies have found different findings, the researchers note. Some studies have shown that some skin parasite infections heal faster in animals fed a high salt diet, and macrophages are particularly active in the presence of salt. Therefore, it is believed that salt may enhance the immune function.
But the researchers point out that salt concentrations in the blood and various organs are generally stable, with the exception of the skin, which acts as a reservoir of salt. This is the reason why taking more salt is effective for some skin diseases.
The researchers pointed out that the number of Listeria in the spleen and liver of mice infected with Listeria on a high salt diet increased 100-1000 times. Similarly, in mice on a high salt diet, urinary tract infections heal slowly.
The researchers also found that healthy volunteers took an extra 6 grams of salt a day, and after a week, their granulocytes in the blood were significantly less able to cope with bacteria. In addition, a high salt diet also leads to increased levels of glucocorticoids.