The incidence of autoimmune diseases such as multiple sclerosis (MS), Type 1 diabetes, rheumatoid arthritis and about 100 others has been on the rise for decades. However the cause of these disorders--thought to be a combination of genetic predisposition and environmental triggers—has largely baffled researchers. Now researchers at Yale School of Medicine, Harvard Medical School and the Broad Institute may have identified a prime suspect in the mystery — dietary salt.
Using a mice model, they demonstrated that salt can induce and worsen destructive immune system responses in mice and that the response involves genes already implicated in a variety of autoimmune diseases.
Acting on a Hunch
The research was inspired, in part, by an observation that eating at fast-food restaurants tended to trigger an increase in production of inflammatory cells, which are mobilized by the immune system to respond to injury or pathogens but which, in autoimmune diseases, attack healthy tissue. On a hunch, the researchers decided to test whether the high salt content in fast food might be the trigger that induces autoimmunity.
In the lab, they found that adding salt to the diet of mice induced production of a type of T cell (Th17) previously associated with autoimmune diseases and that mice on high salt diets developed a more severe form of a multiple sclerosis animal model, experimental autoimmune encephalomyelitis.
The researchers theorize that humans are not genetically selected for the typical Western high salt diet. This may explain the high rates of hypertension and autoimmune disorders as well.
While further study is needed, one researcher on the team is not waiting to act on these findings, “I already recommend that my patients use a low-salt, low-fat diet,” he said. That includes cutting down on processed foods he added.
More About Salt
Autoimmunity is only one of many health concerns related to dietary salt. We take an in-depth look at these concerns and provide tips to reduce your salt intake with, The Truth About Salt: The Good, the Bad, and the Ugly.
Yale School of Medicine
American Autoimmune Related Diseases Association