A diet containing too much salt may play a role in autoimmune diseases such as multiple sclerosis (MS), research has suggested.
Laboratory experiments showed that a type of immune cell linked to MS became more active and aggressive when exposed to raised levels of ordinary table salt, sodium chloride.
The Th17 "helper" T-cells pumped out chemical signals that can trigger an extreme immune reaction.
"In the presence of elevated salt concentrations this increase can be 10 times higher than under usual conditions," said study author Dr Markus Kleinewietfeld, from Yale University in the United States.
In mice, raising dietary salt consumption led to a more severe form of a disease similar to MS. The number of pro-inflammatory Th17 cells in the nervous systems of the mice increased dramatically. High salt intake accelerated the development of ordinary helper T-cells into harmful Th17 cells. The findings are published in the journal Nature.
MS occurs when the body's immune system destroys the insulating fatty myelin that covers nerve fibres. This interferes with the transmission of nerve messages, leading to a range of symptoms including paralysis. At the molecular level, Th17 cells are regulated by salt, said the scientists.
"These findings are an important contribution to the understanding of multiple sclerosis and may offer new targets for a better treatment of the disease," said co-author Dr Ralf Linken, from University Hospital, Erlangen, Germany.
Dr Susan Kohlhaas, head of biomedical research at the MS Society, said: "This is a really interesting study and it's positive to see new avenues of MS research being explored in this way.
"It's still too early, however, to draw firm conclusions on what these findings mean for people with MS but we look forward to seeing the results of further research.
"In the meantime, we recommend that people follow government advice on maintaining a healthy, balanced diet, which includes guidelines on salt intake."