High salt content can affect our health, especially our intestinal microbiota, as shown in a study published in Nature in 2017.
Western diet is usually too salty and we consume much more salt than necessary. ANSES (French Agency for Food) estimates that men consume around 10 g of salt per day, and women around 8 g of salt per day in France while the WHO (World Health Organisation) guidelines recommend reducing salt intake (5 g per day maximum)…
Unfortunately, salt is everywhere in our diet such as bread, cheese, and majority of processed food.
What impacts can high salt intake have on our health, more specifically on our intestinal microbiota ?
It is currently known that salt promotes the development of cardiovascular diseases. However, high salt diet would also unbalance intestinal microbiota, leading to dysbiosis. This was first demonstrated in mice. After eating a diet with high salt content, Lactobacillus population (a beneficial bacterial genus to our health) was severely decimated. This result would be related to the rise in blood pressure and Th17-type immune cells. which are correlated with hypertension and some autoimmune disease such as multiple sclerosis.
Then, some of the mice were given a probiotic, Lactobacillus murinus, in addition to their high salt diet. The researchers found that the adverse effects was nullified by the probiotic : blood pressure and Th17 cells amount decreased whereas Lactobacillus content increased.
In a second step to corroborate their findings in humans, a pilot study on 12 healthy men was conducted. They were subjected to an increased salt intake (6 g a day) for 2 weeks, without changing their eating habits. At the end of the clinical trial, most of Lactobacillus disappeared.
Too much salt seems to have adverse effects on the intestinal microbiota, but mechanisms are not yet known. Following these results, probiotics could be a solution for people with a high salt diet to limit the risk of developing certain cardiovascular or autoimmune diseases.
WILCK N, MATUS MG, KEARNEY SM, OLESEN SW, FORSLUND K, BARTOLOMAEUS H, HAASE S, MAHLER A, BALOGH A, MARKO L, VVEDENSKAYA O, KLEINER FH, TSVETKOV D, KLUG L, COSTEA PI, SUNAGAWA S, MAIER L, RAKOVA N, SCHATZ V, NEUBERT P, FRATZER C, KRANNICH A, GOLLASCH M, GROHME DA, CORTE-REAL BF, GERLACH RG, BASIC M, TYPAS A, WU C, TITZE JM, JANTSCH J, BOSCHMANN M, DECHEND R, KLEINEWIETFELD M, KEMPA S, BORK P, LINKER RA, ALM EJ, MULLER DN. Salt-responsive gut commensal modulates TH17 axis and disease. Nature. 2017, 551(7682):585-9