Although many factors have been studied previously to see if they have a role in the cause and course of MS, dietary salt intake has not been assessed. This study aimed to investigate the effect of salt intake on people with MS.
70 people with relapsing remitting MS (RRMS) in Argentina took part in the study, which followed and assessed them over a period of two years. The researchers also studied a second group of 52 people with RRMS, which were only assessed over a one month period to compare and check the results of the study on the first group.
The study found that those participants who consumed a high level salt had more relapses, more lesions on their brain scans and were also at increased risk of developing further new lesions, than those participants who consumed a low level of salt.
The results suggest that higher salt intake may be associated with an increase in relapses and lesions in people with RRMS. However this was an observational study, so although it can show relationships it cannot prove that salt is the reason for the results observed. The authors conclude that the results suggest further studies are needed to investigate if reduced salt diets could benefit people with MS.
There is widespread evidence that dietary salt (sodium chloride) plays a key role in regulating blood pressure, but high salt consumption can lead to high blood pressure, which puts people at higher risk of heart disease and stroke.
Although many factors have been studied previously to see if they have a role in the cause and course of MS, salt intake has not been assessed. A recent study in an animal model of MS, found that mice fed a high-salt diet developed a more aggressive course of the disease.
This study aimed to investigate the effect of salt intake on people with MS.
How this study was carried out
70 people with relapsing remitting MS (RRMS) in Argentina took part in the study, which followed and assessed them over a period of two years. Each participant had several MRI scans to assess the number of lesions and information was collected about their lifestyle and the number of relapses they had. They also provided urine samples and blood samples which were tested to determine the amount of salt in their diet and also their levels of vitamin D. People who were pregnant or had other conditions that would affect their salt levels were not included in the study.
The researchers also studied a second group of 52 people with RRMS, which were only assessed over a one month period to compare and check the results of the study on the first group.
The groups were divided into three further subgroups based on their salt intake. Low-salt was for those consuming less than 2g a day, medium consumed between 2g and 4.8g a day and the high-salt group was those who consumed more than 4.8g of salt a day.
What was found
The study found that daily intake of salt was an average of 4g a day. Males had a significantly higher salt level than females. After taking into account age, gender, disease duration, drug treatment, vitamin D levels, BMI and smoking status, the study found a relationship between salt intake and increased disease activity.
Those participants who consumed a high level salt had more relapses, more lesions on their brain scans and were also at increased risk of developing further new lesions, than those participants who consumed a low level of salt.
What does it mean?
The results suggest that higher salt intake may be associated with an increase in relapses and lesions in people with RRMS. However this was an observational study, so although it can show relationships it cannot prove that salt is the reason for the results observed. The authors note that the participants who have more relapses may excrete more salt because they have more active MS and not that the salt is causing the more active disease. They conclude that the results suggest further studies are needed to investigate if reduced salt diets could benefit people with MS.
Farez MF, Fiol MP, Gaitán MI, et al.
Sodium intake is associated with increased disease activity in multiple sclerosis..
J Neurol Neurosurg Psychiatry. 2014 Aug 28. pii: jnnp-2014-307928.[Epub ahead of print]
More about salt
A little bit of salt is essential to keep our bodies working properly. It helps nerves and muscles work and it also helps keep the right balance of fluids in your body, controlling blood pressure and blood volume. However too much salt can cause raised blood pressure, which increases the risk of heart disease and stroke.
Previous work in human cells and animal models of MS have shown that too much salt may be bad for MS, affecting the immune system and the course of the disease. Although this study does not prove a link between salt and worsening symptoms in MS, it adds to the data and warrants further investigation.
Low salt in the diet is already recommended for the general population, as research has shown most people eat too much. As high salt is known to be a risk factor for heart disease and stroke, trying to reduce how much salt you eat is a good idea for most people. To reduce the risk of disease, it is recommended that adults should not be eating more than 6g of salt a day. Reducing salt intake is not just about reducing how much salt you put on to your food from the salt mill, but there are some foods that are naturally high in salt. These foods include cheese, smoked meat and fish and bacon, so reducing how often you eat them or the portion size will cut down the amount of salt you eat. Other foods have hidden salt, these include bread, baked beans and many ready meals have high levels of salt.
A lower salt diet should be part of a balanced diet, which includes foods from the major food groups of fruit and vegetables, carbohydrates, fat, protein and dairy products. A balanced diet is essential to provide all the nutrients needed to be as active and healthy as possible. The role of diet in helping people with problems such as eating difficulties, bladder problems and constipation, is now generally accepted. A poor diet and nutrition can also worsen existing symptoms such as fatigue and weakness. However fatigue and some other symptoms can also make consuming a balanced diet more difficult.
There are a number of suggestions in Living with fatigue for reducing the impact of fatigue when preparing and eating meals, but these suggestions can also help reduce the impact on other symptoms as well.You can also read more about diet and MS in the A to Z of MS.
Research by topic areas...
Thomas S, Kersten P, Thomas PW.
The multiple sclerosis-fatigue self- efficacy (MS-FSE) scale: initial validation.
Clin Rehabil. 2014 Aug 26. [Epub ahead of print]
Stellmann JP, Vettorazzi E, Poettgen J, et al.
A 3meter timed tandem walk is an early marker of motor and cerebellar impairment in fully ambulatory MS patients.
J Neurol Sci. 2014 Aug 10. [Epub ahead of print]
Balabanov P, Haas M, Elferink A, et al.
Addressing the regulatory and scientific challenges in multiple sclerosis - a statement from the EU regulators.
Mult Scler. 2014 Sep;20(10):1282-7.
Suh Y, Motl RW, Olsen C, et al.
Pilot trial of a social cognitive theory-based physical activity intervention delivered by non-supervised technology in persons with multiple sclerosis.
J Phys Act Health. 2014 Aug 22. [Epub ahead of print]
Synnot AJ, Hill SJ, Garner KA, et al.
Online health information seeking: how people with multiple sclerosis find, assess and integrate treatment information to manage their health.
Health Expect. 2014 Aug 28. [Epub ahead of print]
Symptoms and symptom management
Leite HF, Leite JD, Melo MH, et al.
Deafness in patients with multiple sclerosis.
Audiol Neurootol. 2014 Aug 20;19(4):261-266. [Epub ahead of print]
Messenger W, Hildebrandt L, Mackensen F, et al.
Characterisation of uveitis in association with multiple sclerosis.
Br J Ophthalmol. 2014 Aug 28. [Epub ahead of print]
Brola W, Mitosek-Szewczyk K, Opara J.
Symptomatology and pathogenesis of different types of pain in multiple sclerosis.
Neurol Neurochir Pol. 2014 July - August;48(4):272-279.
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