Over-consumption of salt has been implicated as a potential cause of some of the autoimmune diseases that people suffer from, such as IBD, multiple sclerosis and rheumatoid arthritis.
Though it has been known for years that salt can contribute to cardiovascular disease, the link between salt and other illnesses has come as a surprise to some scientists, The Guardian reports.
Autoimmune disease are those where the immune system attacks the body itself, and includes eczema, asthma and some bowel disorders.
Over the past three decades, autoimmune disease has risen by between five per cent and seven per cent a year and scientists have failed to reach an explanation for the increase. Researchers have suggested several possible explanations, including environmental toxins, smoking, low levels of vitamin D, increased hygiene levels and certain infections. But none of these theories has provided an adequate answer.
Previously researchers had thought that hypertension was caused by chronic water retention as a result of eating too much salt, but recent research has shown that hypertension is caused by an immune overreaction.
The link was first shown when scientists revealed that people who frequently ate large amounts of fast food had a higher level of a type of cell that causes inflammation in their guts. Researchers hypothesised that salt caused this and showed this was the case in studies on rats.
Last year, a study into patients with multiple sclerosis showed that those who ate a lot of salt were four times more likely to develop more serious symptoms than those who ate little.
Researchers are advising that people with autoimmune disease consider reducing their salt intake, but warn that salt may be only one factor. It could be that certain people are more vulnerable, perhaps those with a higher sensitivity to salt, or a predisposition to autoimmune diseases. They also emphasise that salt is probably just one of several factors that play a role in rising rates of autoimmune disease.
