Salty Diet May Help Trigger Multiple Sclerosis, RA
While salt may play a role in autoimmune diseases, the researchers said the picture is most likely complicated. "We don't think salt is the whole story. It's a new, unexplored part of it, but there are hundreds of genetic variants involved in autoimmune disease and environmental factors, too," said Hafler.
It's also unclear just how much salt is required to stimulate the autoimmune response, Hafler added.
In addition to salt, other factors have been shown to influence levels of helper T-cells, including microbes, diet, metabolism, environmental factors and cytokines (proteins that help regulate inflammatory responses), according to O'Shea, who was not involved with the new studies.
O'Shea said the studies provide a way to test -- hopefully soon in human trials -- whether a low-salt diet might help treat autoimmune disease.
"They have now identified a biomarker, so you could treat people with a low-salt diet and then check for the marker in cells using cell cytometry, for example," O'Shea explained. While such a test is not generally available for consumers, it is found in most research labs, he added.
Hafler pointed out that while salt may be implicated in autoimmune disease, it may also be found to play an important role in boosting the immune system. Part of the reason chicken soup seems to be effective with colds and flu may be that the salt stimulates an infection-fighting response, he said.
Should consumers who are concerned about autoimmune disease switch to a low-salt diet, even before tests in humans have been done?
"If I had an autoimmune disease, I would put myself on a low-salt diet now," Hafler said. "It's not a bad thing to do. But we have to do more studies to prove it."
O'Shea agreed. "But the extent to which salt is important, I think we don't know. These papers show it experimentally, but we still can't be sure," he said.