High-salt diet may kill off 'good' gut bacteria

High salt consumption may kill certain gut bacteria which may lead to high blood pressure and diseases affecting the immune system, says study.

Previous studies have already established a link between high blood pressure and high dietary salt intake. The progression rate of certain autoimmune diseases like multiple sclerosis(MS) was also found to elevate due to high salt diets.

Lactobacillus is a type of gut bacteria found in some fermented foods such as sauerkraut, yogurt, and cheese and is considered "good" bacteria as they are believed to offer protection against certain diseases. According to the latest study, presented at the British Cardiovascular Society Conference in Manchester in the United Kingdom, eating a lot of salt could kill Lactobacillus and thereby increase the risk of disease.

The research was led by scientists from the Experimental and Clinical Research Center and Max Delbruck Center for Molecular Medicine in Berlin, Germany. The researchers found that a version of Lactobacillus found in mice is destroyed when they are fed with a diet high in salt. The high-salt diet increased the blood pressure of mice and triggered the activation of inflammation-inducing immune cells, called TH17 cells. The mice also demonstrated symptoms of a neurological condition similar to multiple sclerosis called encephalomyelitis.

The researchers found that giving the mice a probiotic treatment of Lactobacillus, encephalomyelitis symptoms and TH17 cell count could be reduced, which also stabilized the mice's blood pressure.

After the successful trial in mice, the researchers went a step ahead to carry on the similar trial in humans. 12 healthy men were involved in the study who consumed 6 extra grams of salt each day for 2 weeks, effectively doubling their salt intake.

The authors found that by the end of the 2 weeks in most of the participants, Lactobacillus had been eliminated from their microbiomes. Like the mice, the men in the study also had higher blood pressure and increased TH17 cell count.

The authors concluded that TH17 cells are affected by the gut microbiome but the finding that salt kills off healthy bacteria in the microbiome is new and they believe that more research is to be done on a larger scale to better understand how gut health affects the health of the body's other systems, such as cardiovascular health, and the extent to which probiotics might provide useful treatments for conditions such as high blood pressure.