Scientists investigate whether diet can help prevent fatigue in multiple sclerosis patients.
Multiple sclerosis (MS) is an autoimmune disorder that affects the brain and spinal cord. The body’s immune system attacks the cells (oligodendrocytes) that make the fatty covers that surround nerve cells. This fatty cover is called the myelin sheath, this is why MS is also referred to as a demyelinating disease. The myelin acts like insulation that you see around wires. When this insulation is degraded electrical signals that pass through the wires can be disrupted or lost. The same is true for the electrical signals travelling along a nerve cell.
When the myelin is degraded these signals move more slowly across the cell or they don’t get passed on at all. This prevents the nervous system from being able to send and receive signals from the rest of the body. This breakdown in communication results in the symptoms characteristic of MS such as difficulties with coordination and balance, muscle spasms, weak muscles, double vision, acute and chronic pain, fatigue (feeling tired), bowel and bladder dysfunction, problems with attention, speech, working memory, and spatial reasoning.
Multiple sclerosis and Fatigue
Many patients with MS also suffer from fatigue. Fatigue is considered the most debilitating symptom for multiple sclerosis patients outranking both pain and physical disability. Fatigue appears to be more severe in patients with progressive MS. The cause of fatigue in MS is not well understood, this is because fatigue is particularly difficult to study as it is a subjective symptom, and there is no unified approach to measuring fatigue in patients.
MS-related fatigue is multifactorial, it can either be primary or secondary depending on the cause. Primary fatigue is thought to be caused by the demyelination, nerve damage and immune reactions characteristic of the MS. Secondary fatigue is thought to be caused by some of the symptoms associated with MS such as reduced activity, pain, depression, psychological functioning, medication use, and sleep disturbance.
Can changes in diet help alleviate MS-related fatigue?
In a recent US study published in Plos One, researchers wanted to know if a diet-based intervention could help reduce fatigue MS patients. In this pilot study, scientists followed 18 patients with progressive MS for one year. The scientists asked all 18 patients to incorporate several changes to their lifestyle. This is what the researchers called their “diet-based multimodal intervention” and it included diet, exercise, neuromuscular electrical stimulation, and stress reduction.
The diet was not calorie-restrictive, participants were encouraged to eat until satiation as weight loss was not the main goal. The diet consisted of high intake of fruits and vegetables, consuming both animal and plant protein and exclusion of foods with gluten-containing grains, dairy, and eggs. Participants were asked to perform home-based exercise programs that included stretches and strengthening exercises for leg and trunk muscles. A unique exercise program was designed for each subject.
Patients were also asked to meditate and self-massage hands, feet, and face for 20 minutes daily to encourage stress reduction. The scientists then measured fatigue by using a survey called the Fatigue Severity Scale (FSS). They did this when patients entered the trial and at months three, six, nine, and twelve. They also measured high-density lipoprotein, low-density lipoprotein, total cholesterol, triglycerides, and BMI at the beginning and end of the trial.
The researchers found that after twelve months there was an association between the diet and a reduction of fatigue. The group also found that after a year there was a decrease in the low-density lipoproteins and triglycerides but an increase in high-density lipoproteins. They went on to show there was an association between increases in high-density lipoprotein and reductions in fatigue.
There are numerous limitations in this study that need consideration before the results can be interpreted. The study did not include a control group of individuals who did not receive the diet-based multimodal intervention. This makes it very difficult to interpret the results as the placebo effect is not taken into consideration. This is particularly important when measuring fatigue as previous clinical trials have shown that the placebo effect can substantially bias fatigue reporting. The group did not account for confounding factors like depression, sleep disturbance, and pain all of which have already been shown to predict fatigue in multiple sclerosis.
This could bias the results attained in the trial and was not accounted for.
Additionally, there were no controls for each intervention (diet, exercise, stress reduction, and neuromuscular electrical stimulation) therefore it is difficult to delineate which intervention or combination thereof contributed to the reduction in fatigue. The multimodal nature of the intervention makes it difficult to interpret the results as these are confounding variables and introduce bias in the study. The researchers did not provide any evidence on the causal relationship between diet and fatigue in MS patients. Although there are numerous limitations to this study, the data are encouraging in that it may be the basis for a larger trial that would produce more robust results.
Written by Tarryn Bourhill MSc, PhD Candidate