Science Too much salt dangerously weakens the intestinal flora

Physicians are studying the effects of salt intake

Most people eat too much salt every day. Researchers 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 involved in the development of autoimmune diseases and hypertension.

The scientists of the Max Delbrück Center for Molecular Medicine (MDC) and the Charité-Universitätsmedizin Berlin found in their current study that salt affects the bacteria in the intestine. The experts published the results of their study in the journal "Nature".

Many people may have heard that over-absorption of salt is unhealthy. Researchers have now substantiated this statement with current research results. They found that salt has a negative effect on the bacterial community in our gut. (Image: HandmadePictures / fotolia.com)

How does salt affect the bacteria in the intestine??

The absorption of salt affects some bacteria in the intestine. This, in turn, has effects on the immune cells, which cause autoimmune diseases and hypertension. In experiments on mice, the physicians found that probiotics mitigated the disease symptoms in the animals. We take salt every day, and the amount varies from day to day. Mostly we absorb too much salt. So far, however, has not been studied how salt affects the bacteria in the intestine, explains the study director Professor Dominik Müller of the Berlin Experimental and Clinical Research Center (ECRC) and the Berlin Institute of Health Research (BIH).

Salt can decimate lactobacilli in the gut

If we consume too much saline through our diet, this will increase 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 associated with high blood pressure and autoimmune diseases such as multiple sclerosis.

Microbiome an important factor for the effect of salt

When the animals ingested probiotic lactobacilli concomitantly with the high-salt diet, blood pressure and the number of Th17 helper cells declined again. So-called probiotics also mitigate 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 salt-affected diseases. "Intestinal bacteria affect the host organism, and the immune system in the gut is very active," explains lead author Dr. Nicola Wilck in a press release of the MDC.

Physicians investigate in their study digestive tract of twelve male subjects

The research team also reviewed the bacterial community in the digestive tract of twelve healthy men. These received six additional grams of saline each day for a period of 14 days. Otherwise, the subjects kept 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 taken. Most were no longer detectable after 14 days of increased salt intake. Blood pressure and the number of Th17 helper cells in the blood increased at the same time.

There could be several 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 unknown. "Our study goes beyond the description of salt changes. We wanted to look at coherent processes, "explains study leader Prof. Dominik Müller. Exact interactions are still not fully understood. It can not be ruled out that there are other saline-sensitive bacteria that are equally important, the expert adds.

In the future, multiple sclerosis can be treated with customized probiotics?

So-called lactobacilli are found mainly in fermented foods such as sauerkraut, yogurt or cheese. Although the therapeutic efficacy of these bacteria has not yet been fully proven, "perhaps multiple sclerosis is one of the salt-sensitive diseases that we will be able to treat with customized probiotics in the future," explains neuroimmunologist Prof. Ralf Linker. Lactobacillus probiotics could have therapeutic potential.

Further research is needed

Such potential will soon be reviewed at the ECRC. A blood pressure study with human volunteers is already in the planning, say the experts. Such a double-blind study with a larger number of participants from both sexes, controlled by placebo, is needed before the therapeutic use of probiotics can be considered, the authors explain. (As)