Salt flavors your food nicely – but at the same time it also provides valuable minerals and plays an important role in regulating the water balance in the human organism. Sodium chloride, a component of salt, is also needed for the nervous system, digestion and bone formation – but you should use it sparingly. It has long been known that an excess of table salt in food can cause high blood pressure – but what very few of us know is that the course of multiple sclerosis, an autoimmune disease, can also be negatively influenced by salt.
The normal daily requirement is two to three grams, but this is often exceeded, since most people not only use salt to season their food, they also consume it in many salty processed products.
A team of researchers led by Dominik Müller at the Max Delbrück Center for Molecular Medicine (MDC) in Berlin investigated the effect of high salt consumption on the intestinal flora. The composition of the intestinal flora is becoming more and more important in a wide range of diseases – and is increasingly becoming the focus of research.
The intestinal mucosa is the main habitat of the immune cells, which produce a large army of antibodies, neurotransmitters and defense & scavenger cells to protect the body from foreign substances. Earlier studies have shown that too much table salt in food increases the number of immune cells called “Th17 helper cells”. These cells then produce increased levels of the Interleukin-17 messenger substance, which triggers inflammatory reactions in the blood vessels. Blood pressure increases, and the development of autoimmune diseases can be stimulated as a result.
In the Berlin study, the research team investigated the extent to which the intestinal flora changes due to excessive salt consumption. For two weeks, mice were given 0.3 grams of table salt every day with their food. Examination of the feces samples for the composition of the bacterial species showed that the number of some bacterial species was reduced and that some of them had disappeared completely from the digestive tract – the intestinal bacteria of the genus Lactobacillus, for example, could no longer be detected after 14 days of increased salt intake.
So, to what extent is this result transferable to humans? In a pilot study with twelve healthy men, the researchers tested the composition of bacteria in the digestive tract. The men were given six grams of table salt for 14 days in addition to their normal food. They consumed an average of 12-14 grams of table salt per day. The intestinal bacteria of the genus Lactobacillus also reacted in the test persons – and could not be detected at the end of the test.
Another interesting result of the study was that significantly fewer Th17 helper cells were formed in mice that had been fed a salt-rich diet and probiotic lactobacilli – and their blood pressure also decreased. It is not clear whether lactobacilli, which are mainly found in fermented foods such as sauerkraut, yogurt and cheese, have an effect like that of the probiotic lactobacilli that were added to the food – particularly since the researchers cannot rule out the possibility that there are other salt-sensitive bacterial species that have an important influence on health.
Further studies are necessary to shed more light on this – and the results of these studies may enable us to counteract autoimmune diseases with an individually-adapted probiotic therapy. This is something to look forward to!