Written by Chrystal Moulton, Staff Writer. In this cell and animal study, researchers showed that high salt intake encouraged the production of defective cells of the immune system and increased the risk of developing multiple sclerosis.
Salt has long been seen as a detrimental part of the typical Western diet since many chronic diseases that afflict western countries are linked to overconsumption of salt. These include hypertension, heart disease and even stroke. However, the effect on salt intake in other diseases, especially in this case, multiple sclerosis, has not been determined until now.
A group of researchers have conducted a series of experiments to determine how salt may affect Th17 cells known to influence the development of multiple sclerosis. They ran two separate experiments: one to determine whether salt (Sodium chloride) encourages the production of defective Th17 cells that lead to multiple sclerosis and two to determine if the Th17 cells developed as a result of high salt intake and causes an induced form of multiple sclerosis in mice known in this study as experimental autoimmune encephalomyelitis.
In the first experiment, researchers collected CD4 memory cells from healthy adults to conduct an in vitro study. They then plated collected cells in mediums containing concentrations of sodium ranging from 10-40mM. The dosage range in humans correlates to 584.4 – 2,337.6mg of salt which is a realistic dosage, because the average American consumes close to 3,400 mg of salt daily which is more than was given to the cells in this experiment (2). They found that development of pathogenic or disease Th17 cells increased as salt concentration increased. Maximum pathogenic Th17 expression was observed at 40mM NaCl since increasing salt concentration above 40mM did not increase development of pathogenic Th17 cells. They also tested whether other salt compounds had the same effect on naive CD4 memory cells. Among various salt compounds, sodium gluconate exhibited the same pathogenic effect as sodium chloride.
In the second experiment, researchers induced male mice to develop experimental autoimmune encephalomyelitis (animal model of multiple sclerosis). The mice were then divided into control or experimental groups. Mice received normal chow and tap water in the control group while the experimental group received chow containing 4% NaCl and tap water containing 1% NaCl. Evaluation was conducted daily and progression was rated on a 5 point scale from 0 (no clinical sign) to 5 (diseased). They found that the high salt diet accelerated the onset and increased the severity of the disease. Th17 cell expression doubled in frequency in the central nervous system and spleen.
Source: Kleinewietfeld, Markus, et al. “Sodium chloride drives autoimmune disease by the induction of pathogenic TH17 cells.” Nature 496.7446 (2013): 518-522.
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Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Sodium chloride drives autoimmune disease by the induction of pathogenic TH17 cells. Kleinewietfeld M, Manzel A, Titze J. Nature. 2013 Mar 6. doi: 10.1038/nature11868. [Epub ahead of print]
- Ajani, Umed A., et al. “Sodium intake among people with normal and high blood pressure.” American journal of preventive medicine 29.5 (2005): 63-67.
