How can you protect your intestinal microbiota? Avoid excess salt

Consuming excessive amounts of salt favors the development of high blood pressure and cardiovascular diseases. Our gut and its microbiota--in direct contact with salt from food—may be the new key players in these diseases.

For the first time, German researchers have studied the effects of salt consumption on the intestinal microbiota. They based their research on current knowledge, which has established an association between high-salt meals and an inflammatory reaction in the body (a defense response characterized by an increase in pro-inflammatory cells). This reaction promotes the development of hypertension and certain autoimmune diseases, caused by immune dysfunction and often associated with significant cardiovascular risk. The researchers also relied on the established role of the intestinal microbiota---heavily influenced by diet--in regulating the immune system and controlling pro-inflammatory cells.

The team hypothesized that imbalance in the microbial system could lead to the development of hypertension and certain autoimmune diseases. They tested the hypothesis in mice with hypertension and an autoimmune disease. Elevated salt consumption led to a significant drop in lactobacilli in the intestinal microbiota. Correcting the imbalance with a supplement of lactobacilli led to reductions in inflammation and blood pressure. It also prevented aggravation of the autoimmune disease. In humans, when healthy subjects consumed three teaspoons of salt daily (around 14g, more than twice the maximum recommended daily intake), it had the same impact on the intestinal microbiota, increasing blood pressure and the production of pro-inflammatory cells.

The results suggest that salt consumption may partially contribute to the loss of lactobacilli and play a role in the development of hypertension and autoimmune diseases. The researchers say lactobacilli should be considered as a tool to modulate the microbiota, and as a promising research avenue for innovative preventative treatments and therapies.

Sources :

Wilck N et al. Salt-responsive gut commensal modulates TH17 axis and disease. Nature 2017 ;551: 585-589