Doctors are studying the effects of salt consumption
Most people consume too much salt every day. Researchers have now found that salt in mice and humans reduces the number of certain lactic acid bacteria in the gut. This then affects the immune cells that are involved in the development of autoimmune diseases and high blood pressure.
The scientists at the Max Delbrück Center for Molecular Medicine (MDC) and the Charité – Universitätsmedizin Berlin discovered in their current study that salt affects the bacteria in the intestine. The experts published the results of their study in the journal "Nature".
How does salt affect the bacteria in the intestine?
The absorption of salt affects some bacteria in the intestine. This in turn has an impact on the immune cells, which also cause autoimmune diseases and high blood pressure. In experiments on mice, the doctors were able to find that probiotics alleviated the symptoms of the disease in the animals. We consume salt every day, and the amount varies from day to day. Most of the time we take in too much salt. To date, however, it has not yet been investigated how salt influences the bacteria in the intestine, explains study leader Professor Dominik Müller from the Berlin Experimental and Clinical Research Center (ECRC) and the Berlin Institute for Health Research (BIH).
Salt can decimate lactobacilli in the intestine
If we consume too much table salt from our food, this will promote high blood pressure and, for example, negatively affect the course of the autoimmune disease multiple sclerosis. In experiments on mice, it was found that an excess of salt decimates the so-called lactobacilli in the intestine. In addition, blood pressure and the number of Th17 helper cells increased. The latter are linked to high blood pressure and autoimmune diseases such as multiple sclerosis.
Microbiome an important factor for the effect of salt
If the animals ingested probiotic lactobacilli in addition to the salt-rich food in the experiment, the blood pressure and the number of Th17 helper cells decreased again. So-called probiotics also alleviate the neurological symptoms of experimental autoimmune encephalomyelitis, a disease model for multiple sclerosis, the researchers explain. In other words, the scientists found that the microbiome is an important factor in diseases influenced by salt. "Gut bacteria influence the host organism, and the immune system is also very active in the gut," explains first author Dr. Nicola Wilck in a press release from the MDC.
In their study, doctors examine the digestive tract of twelve male test subjects
The research team also checked the bacterial community in the digestive tract of twelve healthy men. They were given an additional six grams of table salt every day for 14 days. Otherwise, the subjects maintained their normal eating habits, so that the total daily salt intake was doubled. The intestinal bacteria of the genus Lactobacillus were extremely sensitive to the amount of salt ingested. Most were undetectable after 14 days of increased salt intake. Blood pressure and the number of Th17 helper cells in the blood rose at the same time.
There could be various other bacteria that are sensitive to salt
More and more studies are concerned with the importance of intestinal bacteria in diseases. The interaction of the intestinal flora with the organism is largely still unknown. “Our study goes beyond describing the changes caused by salt. We wanted to look at related processes, ”explains study leader Prof. Dominik Müller. Exact interactions are still not fully understood. It cannot be ruled out that there are other salt-sensitive bacteria that are of similar importance, the expert adds.
Can multiple sclerosis be treated with customized probiotics in the future?
So-called lactobacilli are mainly found in fermented dishes such as sauerkraut, yoghurt or cheese. Although the therapeutic efficacy of these bacteria has not yet been fully demonstrated, "multiple sclerosis may be one of the salt-sensitive diseases that we can treat with individually adapted probiotics in the future," explains neuroimmunologist Prof. Ralf Linker. Lactobacillus probiotics could therefore have therapeutic potential.
More research is needed
Such potential will soon be examined at the ECRC. A blood pressure study with human subjects is already being planned, say the experts. Such a double-blind study with a large number of participants from both sexes, controlled by placebo, was necessary before one could think about the therapeutic use of probiotics, the authors explain. (as)