A diet high in salt can worsen multiple sclerosis (MS) symptoms, as well as increase the risks of neurological deterioration, according to an observational study led by Mauricio Farez, from the Universidad del Salvador in Buenos Aires, Argentina and recently published at the Journal of Neurology, Neurosurgery & Psychiatry, entitled, “Sodium intake is associated with increased disease activity in multiple sclerosis.” Although there were no definitive conclusions about its causes or effects, the research suggests a confirmation of other previous studies that discouraged MS patients to use great amounts of salt.
The researchers demonstrated that patients who consumed more salt every day suffered, on a moderate to high intake basis, around three more episodes of worsening symptoms compared to patients who consumed less salt. The same group was also four times as likely to have these episodes. When analyzing the patients’ x-rays and scans, they also verified that the disease had progressed more on the first group, and were able to establish a link between dietary salt intake and radiological indications of neurological deterioration.
During the research, 70 people suffering from relapsing-remitting multiple sclerosis (RRMS) were analyzed with blood and urine samples to verify the levels of salt, creatinine, which is a marker of inflammatory activity, and vitamin D, in which low levels are associated with the disease. The exams were performed on three separate occasions during nine months, and researchers searched for changes in dietary salt intake, as well as neurological health. The parameters were verified for two years, between 2010 and 2012.
“Recently, salt has been shown to modulate the differentiation of human and mouse Th17 cells and mice that were fed a high-sodium diet were described to develop more aggressive courses of experimental autoimmune encephalomyelitis,” explained the authors in their paper. “However, the role of sodium intake in multiple sclerosis (MS) has not been addressed. We aimed to investigate the relationship between salt consumption and clinical and radiological disease activity in MS. Our results suggest that a higher sodium intake is associated with increased clinical and radiological disease activity in patients with MS.”
To compare the results, the scientists measured the same parameters of urinary salt levels in a second group of 52 people also with RRMS between June and July 2013. The research team verified that the average salt intake was over four grams per day in both groups, varying from under 2 g (low) to 2-4.8 g (moderate) to 4.8 g or more a day (high). They also noted that men have a higher daily intake than women. The observational study also took into consideration elements like smoking, age, gender, length of time after diagnosis, weight, treatment and circulating vitamin D.
Although in an observational study no scientific conclusions are made, the researchers were able to establish the link between high levels of salt in the urine and disease activity, and the authors recalled that high salt intake is associated with poor health in diverse levels. The next step for the team is to perform a further study to understand if the contrary is also true, to see if dietary salt reduction could reduce the symptoms of the disease or slow its progression.