There is a link between autoimmunity and salt intake that can be traced back to the interaction with salt on the immune cells residing in the intestine. About five years ago, a couple of studies showed that high salt intake leads to fundamental immune changes in the gut, resulting in increased vulnerability of the brain to autoimmunity— a condition in which the immune system attacks its own healthy cells and tissues by mistake, suggesting that perhaps the gut can communicate with the brain via immune signaling.
New research in mice has shown how excessive salt intake can make the brain vessels vulnerable and lead to stroke (similar mechanism as leading to heart attack), irrespective of high blood pressure, which is conventionally seen as a major risk factor for stroke. The researchers found that immune responses in the small intestines set off a chain of chemical responses that reduced blood flow to the cortex and the hippocampus, two brain regions integral to learning and memory, bringing about cognitive decline. This impact due to salt overload was even seen in the absence of high blood pressure.
Understanding this vital link between a healthy low salt diet and the gut´s immune signaling is an important reminder of why reducing the stressor of excessive salt intake and paying attention to a balanced, healthy diet is key to preserving our mental health.
See the following article published in Science magazine this December for more.